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  • 201.
    Sergeyev, Sergey
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Migration-assisted upconversion in high-concentration EDFA with electronic feed-forward gain control2006Ingår i: CLEO/QELS 2006, Optical Society of America, 2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    Accounting for statistical nature of migration and upconversion, we develop a new model of high-concentration EDFA with an electronic feed-forward gain control. Unlike homogeneous upconversion model, this model shows complete agreement with experimental data.

  • 202.
    Sergeyev, Sergey
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Migration-assisted upconversion in high-concentration EDFA with electronic feed-forward gain control2005Ingår i: 2005 Quantum Electronics and Laser Science Conference (QELS), 2005, s. 1358-1360Konferensbidrag (Refereegranskat)
    Abstract [en]

    Accounting for statistical nature of migration and upconversion, we develop a new model of high-concentration EDFA with an electronic feed-forward gain control. Unlike homogeneous upconversion model, this model shows complete agreement with experimental data.

  • 203. Sergeyev, Sergey
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Raman amplification with reduced polarization impairments in the fibre with tailored spin profile2010Ingår i: Central European Journal of Physics, ISSN 1895-1082, E-ISSN 1644-3608, ISSN 1895-1082 print, Vol. 8, nr 2, s. 164-168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By using two-section fibre where the first section has no spin and the second one is periodically spun, we demonstrate reduced polarization dependent gain and polarization mode dispersion (0.3 dB and 0.0072 ps center dot km(-1/2) correspondently) in a distributed fibre Raman amplifier.

  • 204. Sergeyev, Sergey
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Friberg, Ari T.
    Virtually Isotropic Transmission Media With Fiber Raman Amplifier2010Ingår i: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 46, nr 10, s. 1492-1497Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report a theoretical study and simulations of a novel fiber-spin tailoring technique to suppress the polarization impairments, namely polarization mode dispersion and polarization dependent gain (PDG), in fiber Raman amplifiers. Whereas use of depolarizer or multiplexing pump laser diodes with a final degree of pump polarization of 1% for periodically spun fiber results in PDG of about 0.3 dB, we demonstrate that application of just a two-section fiber (where the first part is short and has no spin, and the second one is periodically spun) can reduce the PDG to as low as below 0.1 dB.

  • 205. Sergeyev, Sergey
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Khoptyar, Dmitry
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Flavin, Donal
    Statistical model of migration-assisted upconversion in a high-concentration erbium-doped fiber amplifier2006Ingår i: Journal of the Optical Society of America. B, Optical physics, ISSN 0740-3224, E-ISSN 1520-8540, Vol. 23, nr 8, s. 1540-1543Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report a new model of a high-concentration erbium-doped fiber amplifier (EDFA) accounting for the statistical nature of the migration and up-conversion processes. By fitting experimental results, we conclude that the statistical model shows better applicability for the characterization of high-concentration EDFAs than the model accounting for the homogeneous upconversion and pair-induced quenching.

  • 206.
    Sergeyev, Sergey V.
    et al.
    Aston Univ, Aston Inst Photon Technol, Birmingham B4 7ET, W Midlands, England..
    Mou, Chengbo
    Aston Univ, Aston Inst Photon Technol, Birmingham B4 7ET, W Midlands, England..
    Habruseva, Tatiana
    Aston Univ, Aston Inst Photon Technol, Birmingham B4 7ET, W Midlands, England..
    Tsatourian, Veronika
    Aston Univ, Aston Inst Photon Technol, Birmingham B4 7ET, W Midlands, England..
    Jacobsen, Gunnar
    Acreo AB, Elect 236, SE-16440 Kista, Sweden..
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Turitsyn, Sergei K.
    Aston Univ, Aston Inst Photon Technol, Birmingham B4 7ET, W Midlands, England..
    Vector Solitons in Mode Locked Fibre Lasers2014Ingår i: 2014 16TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON) / [ed] Jaworski, M Marciniak, M, IEEE , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    We overview our recent results on polarisation dynamics of vector solitons in erbium doped fibre laser mode locked with carbon nanotubes. Our experimental and theoretical study revealed new families of vector solitons for fundamental and bound-state soliton operations. The observed scenario of the evolution of the states of polarisation (SOPs) on the Poincare sphere includes fast polarisation switching between two and three SOPs along with slow SOP evolution on a double scroll chaotic attractor. The underlying physics presents an interplay between effects of birefringence of the laser cavity and light induced anisotropy caused by polarisation hole burning.

  • 207. Sergeyev, Sergey V.
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Polarization-dependent gain and gain fluctuations in a fiber Raman amplifier2007Ingår i: Journal of Optics. A, Pure and applied optics, ISSN 1464-4258, E-ISSN 1741-3567, Vol. 9, nr 12, s. 1119-1122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report a new vector model of a fiber Raman amplifier with a randomly varying birefringence. We find that the analysis of gain fluctuations and polarization-dependent gain can be used for measurements of beat and birefringence correlation lengths and the polarization mode dispersion value on a long single-mode fiber. Results are consistent with a standard technique based on differential group delay measurements.

  • 208. Sergeyev, S.V
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Two-section fiber optic Raman polarizer for high-speed transmission systems2011Ingår i: 2011 13TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON) / [ed] Jaworski, M; Marciniak, M, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report on a theoretical study of polarization impairments in periodically spun fiber Raman amplifiers. Based on the Stochastic Generator approach we have derived equations for polarization dependent gain and mean-square gain fluctuations. We show that periodically spun fiber can work as a Raman polarizer but it suffers from increased polarization dependent gain and gain fluctuations. Unlike this, application of a depolarizer can result in suppression of polarization dependent gain and gain fluctuations. We demonstrate that it is possible to design a new fiber Raman polarizer by combining a short fiber without spin and properly chosen parameters and a long periodically spun fiber. This polarizer provides almost the same polarization pulling for all input signal states of polarization and so have very small polarization dependent gain. The obtained results can be used in high-speed fiber optic communication for design of quasi-isotropic spatially and spectrally transparent media with increased Raman gain.

  • 209. Soltanmoradi, Reyhaneh
    et al.
    Wang, Q.
    Qiu, M.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Yan, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Near-infrared light absorption and scattering based on a mono-layer of gold nanoparticles2015Ingår i: Journal of the European Optical Society - Rapid Publications, ISSN 1990-2573, E-ISSN 1990-2573, Vol. 10, artikel-id 15031Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report fabrication and characterization of large-area ultrathin near-infrared light absorbers and scatterers based on a mono-layer of gold nanoparticles laying on top of a dielectric spacer and an aluminum reflector. The nanoparticles are formed through thermal annealing of an evaporated continuous gold film. Through optimization of initial gold-film thickness, spacer thickness, as well as annealing temperature we obtained samples that exhibit very low (similar to 2%) broadband specular reflectance at near-infrared (NIR) wavelength range. By considering also diffuse reflection, we identify that the low specular reflectance can be due to either relatively high light absorption (similar to 70%) or high light scattering (over 60%), with the latter achieved for samples having relatively sparse gold nanoparticles. Both strong absorption and scattering of NIR light are not inherent properties of the bulk materials used for fabricating the samples. Such composite optical surfaces can potentially be integrated to solar-energy harvesting and LED devices.

  • 210.
    Soltanmoradi, Reyhaneh
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Wang, Q.
    Qiu, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO. State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University, China.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Yan, Min
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Near-infrared light absorption and scattering based on a mono-layer of gold nanoparticlesManuskript (preprint) (Övrigt vetenskapligt)
  • 211.
    Sugunan, Abhilash
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Zhao, Yichen
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Mitra, Somak
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Dong, Lin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Li, Shanghua
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Marcinkevicius, Saulius
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Toprak, Muhammet S.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Muhammed, Mamoun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Synthesis of tetrahedral quasi-type-II CdSe-CdS core-shell quantum dots2011Ingår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 22, nr 42, s. 425202-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Synthesis of colloidal nanocrystals of II-VI semiconductor materials has been refined in recent decades and their size dependent optoelectronic properties have been well established. Here we report a facile synthesis of CdSe-CdS core-shell heterostructures using a two-step hot injection process. Red-shifts in absorption and photoluminescence spectra show that the obtained quantum dots have quasi-type-II alignment of energy levels. The obtained nanocrystals have a heterostructure with a large and highly faceted tetrahedral CdS shell grown epitaxially over a spherical CdSe core. The obtained morphology as well as high resolution electron microscopy confirms that the tetrahedral shell have a zinc blende crystal structure. A phenomenological mechanism for the growth and morphology of the nanocrystals is discussed.

  • 212. Udalcovs, A.
    et al.
    Lin, Rui
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, O.
    Gan, L.
    Zhang, Lu
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Pang, X.
    Schatz, Richard
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Djupsjöbacka, A.
    Tang, M.
    Fu, S.
    Liu, D.
    Tong, W.
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Jacobsen, G.
    Chen, Jiajia
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Inter-Core Crosstalk in Multicore Fibers: Impact on 56-Gbaud/λ/Core PAM-4 Transmission2018Ingår i: European Conference on Optical Communication, ECOC, Institute of Electrical and Electronics Engineers Inc. , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    We experimentally demonstrate the impact of inter-core crosstalk in multicore fibers on 56-Gbaud PAM-4 signal quality after 2.5-km transmission over a weakly-coupled and uncoupled seven-core fibers, revealing the crosstalk dependence on carrier central wavelength in range of 1540-1560 nm.

  • 213.
    Udalcovs, A.
    et al.
    Sweden.
    Pang, Xiaodan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, O.
    Sweden.
    Lin, Rui
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Gan, L.
    China.
    Schatz, Richard
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Djupsjöbacka, A.
    Sweden.
    Mårtensson, J.
    Sweden.
    Tang, M.
    China.
    Fu, S.
    China.
    Liu, D.
    China.
    Tong, W.
    China.
    Chen, Jiajia
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Jacobsen, G.
    Sweden.
    MCF-enabled self-homodyne 16/64QAM transmission for SDM optical access networks2018Ingår i: Optics InfoBase Conference Papers, OSA - The Optical Society , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    We experimentally demonstrate a 28-Gbaud circular and square 16/64QAM transmission over a 33.6-km long seven-core fiber with the LO passed through one of the cores for self-homodyne coherent detection employing a low-complexity digital signal processing.

  • 214.
    Udalcovs, Aleksejs
    et al.
    KTH.
    Schatz, Richard
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Monti, Paolo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS.
    Ozolins, Oskars
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Pang, Xiaodan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Navarro, Julien R. G.
    KTH, Skolan för teknikvetenskap (SCI).
    Kakkar, Aditya
    KTH, Skolan för teknikvetenskap (SCI).
    Louchet, H.
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Jacobsen, Gunnar
    Quantifying spectral and energy efficiency limitations of WDM networks due to crosstalk in optical nodes2017Ingår i: Optics InfoBase Conference Papers, OSA - The Optical Society , 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    We demonstrate the significant impact of crosstalk between add and drop ports at optical nodes on energy-efficiency per Hertz in WDM networks employing 32/64 Gbd DP-16QAM transmission, especially when the isolation is reduced to 30dB.

  • 215.
    Van Kerrebrouck, J.
    et al.
    Univ Ghent, Imec, INTEC, IDLab, Ghent, Belgium..
    Zhang, Lijia
    KTH. Shanghai Jiao Tong Univ, SE IEE, Shanghai, Peoples R China..
    Lin, Rui
    KTH.
    Pang, Xiaodan
    KTH. RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Udalcovs, A.
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Ozolins, O.
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Spiga, S.
    Walter Schottky Inst, Coulombwall 4, Garching, Germany..
    Amann, M. C.
    Walter Schottky Inst, Coulombwall 4, Garching, Germany..
    Van Steenberge, G.
    Univ Ghent, Imec, INTEC, CMST, Ghent, Belgium..
    Gan, L.
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Tang, M.
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Fu, S.
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Schatz, Richard
    KTH.
    Popov, Sergei
    KTH.
    Liu, D.
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Tong, W.
    Yangtze Opt Fiber & Cable Joint Stock Ltd Co, Wuhan, Hubei, Peoples R China..
    Xiao, S.
    Shanghai Jiao Tong Univ, SE IEE, Shanghai, Peoples R China..
    Torfs, G.
    Univ Ghent, Imec, INTEC, IDLab, Ghent, Belgium..
    Chen, Jiajia
    KTH.
    Bauwelinck, J.
    Univ Ghent, Imec, INTEC, IDLab, Ghent, Belgium..
    Yin, X.
    Univ Ghent, Imec, INTEC, IDLab, Ghent, Belgium..
    726.7-Gb/s 1.5-mu m Single-Mode VCSEL Discrete Multi-Tone Transmission over 2.5-km Multicore Fiber2018Ingår i: 2018 Optical Fiber Communications Conference and Exposition, OFC 2018 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    A 107Gb/s net-rate DMT optical signal was generated using a single-mode long-wavelength VCSEL with a modulation bandwidth of 23GHz. We experimentally demonstrated a total net-rate up to 726.7Gb/s at 1.5 mu m over 2.5km 7-core dispersion-uncompensated MCF.

  • 216. Van Kerrebrouck, J.
    et al.
    Zhang, Lu
    KTH, Skolan för informations- och kommunikationsteknik (ICT). Shanghai Jiao Tong University, Shanghai, China.
    Lin, Rui
    KTH, Skolan för informations- och kommunikationsteknik (ICT). uazhong University of Science and Technology, Wuhan, China.
    Pang, Xiaodan
    Networking and Transmission Laboratory, RISE Acreo AB, Kista, Sweden.
    Udalcovs, A.
    Ozolins, O.
    Spiga, S.
    Amann, M. C.
    Van Steenberge, G.
    Gan, L.
    Tang, M.
    Fu, S.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Liu, D.
    Tong, W.
    Xiao, S.
    Torfs, G.
    Chen, Jia
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Bauwelinck, J.
    Yin, X.
    726.7-Gb/s 1.5-μm single-mode VCSEL discrete multi-tone transmission over 2.5-km multicore fiber2018Ingår i: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    A 107Gb/s net-rate DMT optical signal was generated using a single-mode longwavelength VCSEL with a modulation bandwidth of 23GHz. We experimentally demonstrated a total net-rate up to 726.7Gb/s at 1.5μm over 2.5km 7-core dispersion-uncompensated MCF.

  • 217.
    Van Kerrebrouck, Joris
    et al.
    Univ Ghent, IMEC, IDLab, Dept Informat Technol, B-9000 Ghent, Belgium..
    Pang, Xiaodan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, Oskars
    RISE Acreo AB, NETLAB, S-16425 Kista, Sweden..
    Lin, Rui
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Udalcovs, Aleksejs
    RISE Acreo AB, NETLAB, S-16425 Kista, Sweden..
    Zhang, Lu
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Li, Haolin
    Univ Ghent, IMEC, IDLab, Dept Informat Technol, B-9000 Ghent, Belgium..
    Spiga, Silvia
    Tech Univ Munich, Walter Schottky Inst, D-85748 Garching, Germany..
    Amann, Markus-Christian
    Tech Univ Munich, Walter Schottky Inst, D-85748 Garching, Germany..
    Gan, Lin
    Huazhong Univ Sci & Technol, Wuhan Natl Lab Optoelect, Wuhan 430074, Hubei, Peoples R China..
    Tang, Ming
    Huazhong Univ Sci & Technol, Wuhan Natl Lab Optoelect, Wuhan 430074, Hubei, Peoples R China..
    Fu, Songnian
    Huazhong Univ Sci & Technol, Wuhan Natl Lab Optoelect, Wuhan 430074, Hubei, Peoples R China..
    Schatz, Richard
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Jacobsen, Gunnar
    RISE Acreo AB, NETLAB, S-16425 Kista, Sweden..
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Liu, Deming
    Huazhong Univ Sci & Technol, Wuhan Natl Lab Optoelect, Wuhan 430074, Hubei, Peoples R China..
    Tong, Weijun
    Yangtze Opt Fibre & Cable Co Ltd, Wuhan 430073, Hubei, Peoples R China..
    Torfs, Guy
    Univ Ghent, IMEC, IDLab, Dept Informat Technol, B-9000 Ghent, Belgium..
    Bauwelinck, Johan
    Univ Ghent, IMEC, IDLab, Dept Informat Technol, B-9000 Ghent, Belgium..
    Chen, Jiajia
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Yin, Xin
    Univ Ghent, IMEC, IDLab, Dept Informat Technol, B-9000 Ghent, Belgium..
    High-Speed PAM4-Based Optical SDM Interconnects With Directly Modulated Long-Wavelength VCSEL2019Ingår i: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 37, nr 2, s. 356-362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports the demonstration of high-speed PAM-4 transmission using a 1.5-mu m single-mode vertical cavity surface emitting laser (SM-VCSEL) over multicore fiber with 7 cores over different distances. We have successfully generated up to 70 Gbaud 4-level pulse amplitude modulation (PAM-4) signals with a VCSEL in optical back-to-back, and transmitted 50 Gbaud PAM-4 signals over both 1-km dispersion-uncompensated and 10-km dispersion-compensated in each core, enabling a total data throughput of 700 Gbps over the 7-core fiber. Moreover, 56 Gbaud PAM-4 over 1-km have also been shown, whereby unfortunately not all cores provide the required 3.8 x 10(-3) bit error rate (BER) for the 7% overhead-hard decision forward error correction (7% OH-HDFEC). The limited bandwidth of the VCSEL and the adverse chromatic dispersion of the fiber are suppressed with preequalization based on accurate end-to-end channel characterizations. With a digital postequalization, BER performance below the 7% OH-HDFEC limit is achieved over all cores. The demonstrated results show a great potential to realize high-capacity and compact short-reach optical interconnects for data centers.

  • 218.
    Vasileva, Elena
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Baitenov, Adil
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Chen, Hui
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sychugov, Ilya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Yan, Min
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Effect of transparent wood on the polarization degree of light2019Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 44, nr 12, s. 2962-2965Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on the study of polarization properties of light propagating through transparent wood (TW), which is an anisotropically scattering medium, and consider two cases: completely polarized and totally unpolarized light. It was demonstrated that scattered light distribution is affected by the polarization state of incident light. Scattering is the most efficient for light polarized parallel to cellulose fibers. Furthermore, unpolarized light becomes partially polarized (with a polarization degree of 50%) after propagating through the TW. In the case of totally polarized incident light, however, the degree of polarization of transmitted light is decreased, in an extreme case to a few percent, and reveals an unusual angular dependence on the material orientation. The internal hierarchical complex structure of the material, in particular cellulose fibrils organized in lamellae, is believed to be responsible for the change of the light polarization degree. It was demonstrated that the depolarization properties are determined by the angle between the polarization of light and the wood fibers, emphasizing the impact of their internal structure, unique for different wood species.

  • 219.
    Vasileva, Elena
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Chen, Hui
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Sychugov, Ilya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Yan, Max
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Light Scattering by Structurally Anisotropic Media: A Benchmark with Transparent Wood2018Ingår i: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 6, nr 23, artikel-id 1800999Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transparent wood (TW) is a biocomposite material with hierarchical structure, which exhibits high optical transmittance and anisotropic light scattering. Here, the relation between anisotropic scattering and the internal structure of transparent wood is experimentally studied and the dependence of scattering anisotropy on material thickness, which characterizes the fraction of ballistic photons in the propagating light, is shown. The limitations of the conven-tional haze, as it is implemented to isotropic materials, are discussed, and a modified characteristic parameter of light scattering—the degree of aniso-tropic scattering is defined. This parameter together with the transport mean free path value is more practical and convenient for characterization of the material scattering properties. It is believed that the generic routine described in this paper can be applied for scattering characterization and comparison of other TW materials of either different thickness, optical quality or based on various wood species.

  • 220.
    Vasileva, Elena
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Fei, Ye
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Funktionella material, FNM.
    Marinins, Aleksandrs
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Etcheverry, Sebastián
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Toprak, Muhammet
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Popov, Sergei Yu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Optimization of optical gain in composite materials containing Rh6G dye and gold nanoparticles2015Ingår i: Asia Communications and Photonics Conference, ACPC 2015, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    The existence of metal nanoparticles in a dye material can lead not only to quenching or enhancement of dye luminescence, or random lasing action, but also to the change of the fundamental material characteristic as optical gain. © 2015 OSA.

  • 221.
    Vasileva, Elena
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Li, Yuanyuan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Sychugov, Ilya
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Mensi, Mounir
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Lasing from Organic Dye Molecules Embedded in Transparent Wood2017Ingår i: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 5, nr 10, artikel-id 1700057Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The report on a study of laser emission from a conceptually new organic material based on transparent wood (TW) with embedded dye Rhodamine 6G molecules is presented in this paper. The lasing performance is compared to a reference organic material containing dye in a poly-methyl-methacrylate matrix. From experimental results, one can conclude that the optical feedback in dye-TW material is realized within cellulose fibers, which play the role of tiny optical resonators. Therefore, the output emission is a collective contribution of individual resonators. Due to this fact, as well as low Q-factor of the resonators/fibers and their length variation, the spectral line of laser emission is broadened up to several nanometers.

  • 222.
    Vasileva, Elena
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Li, Yuanyuan
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Sytjugov, Ilya
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Transparent wood as a novel material for non-cavity laser2014Ingår i: Optics InfoBase Conference Papers, OSA - The Optical Society , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this work we have demonstrated conceptually new organic wood based laser. The laser action is supported by strong scattering due to structural properties of the host material (transparent wood) and can be characterized as quasi random lasing.

  • 223. Verplaetse, Michiel
    et al.
    Lin, Rui
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Van Kerrebrouck, Joris
    Ozolins, Oskars
    De Keulenaer, Timothy
    Pang, Xiaodan
    Pierco, Ramses
    Vaernewyck, Renato
    Vyncke, Arno
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Jacobsen, Gunnar
    KTH, Skolan för informations- och kommunikationsteknik (ICT). Acreo Swedish ICT AB, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Torfs, Guy
    Bauwelinck, Johan
    Yin, Xin
    Real-Time 100 Gb/s Transmission Using Three-Level Electrical Duobinary Modulation for Short-Reach Optical Interconnects2017Ingår i: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 35, nr 7, s. 1313-1319Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrical duobinary modulation is considered as a promising way to realize high capacity because of the low bandwidth requirement on the optical/electrical components and high tolerance toward chromatic dispersion. In this paper, we demonstrate a 100 Gb/s electrical duobinary transmission over 2 km standard single-mode fiber reaching a bit error rate under 7% HD-FEC threshold with the use of PRBS7. This link is tested in real-time without any form of digital signal processing. In-house developed SiGe BiCMOS transmitter and receiver ICs are used to drive an electroabsorption modulated laser and decode the received signal from a PIN-photodiode. The performance of 50 and 70 Gb/s nonreturn-to-zero and electrical duobinary transmission are investigated for comparison.

  • 224.
    Wang, Ke
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101). Acreo AB, Kista, Sweden .
    Li, J.
    Djupsjöbacka, A.
    Chacinski, Marek
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101).
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101).
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101).
    Jacobsen, Gunnar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101). Acreo AB, Kista, Sweden .
    Hurm, V.
    Makon, R. E.
    Driad, R.
    Walcher, H.
    Rosenzweig, J.
    Steffan, A. G.
    Mekonnen, G. G.
    Bach, H. -. G.
    100 Gb/s complete ETDM system based on monolithically integrated transmitter and receiver modules2010Ingår i: 2010 Conference on Optical Fiber Communication, Collocated National Fiber Optic Engineers Conference, OFC/NFOEC 2010, 2010, s. 5465571-Konferensbidrag (Refereegranskat)
    Abstract [en]

    A complete ETDM system based on monolithically integrated transmitter and receiver modules was demonstrated with BER performance below FEC threshold up to 107 Gb/s. ETDM signal at 112 Gb/s with clear eye opening was also observed.

  • 225.
    Wang, Ke
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101). Beijing Institute of Technology, China .
    Li, J.
    Djupsjöbacka, A.
    Chaciński, Marek
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik (Stängd 20120101), Materialfysik, MF (Stängd 20120101).
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Popov, Sergei Yu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Jacobsen, G.
    Hurm, V.
    Makon, R. E.
    Driad, R.
    Walcher, H.
    Rosenzweig, J.
    Steffan, A. G.
    Giorgis Mekonnen, G.
    Bach, H. -G
    Li, Z.
    Friberg, Ari
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    100-112 Gbit/s complete ETDM systems based on monolithically integrated transmitter and receiver modules2011Ingår i: Journal of Beijing Institute of Technology (English Edition), ISSN 1004-0579, Vol. 20, nr 3, s. 410-414Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditional intensity modulated two-level electrical time-division multiplexing (ETDM) transmission systems working at 100-112 Gbit/s were investigated. The complete ETDM systems based on monolithically integrated transmitter and receiver modules were demonstrated with bit-error-rate (BER) performance of 10-8 at 107 Gbit/s, and near error-free standard forward error correction (FEC) threshold (2×10-3) at 112 Gbit/s. The experiment results showed that directly modulated high-speed ETDM transmission systems with the symbol rates at 100 Gbaud and beyond were promising candidate for cost-effective 100 GbE applications and might be a preform of the next generation of Terabit/s Ethernet.

  • 226.
    Wang, Ke
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101). Beijing Institute of Technology, China.
    Li, J.
    Djupsjöbacka, A.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Jacobsen, G.
    Makon, R. E.
    Driad, R.
    Walcher, H.
    Steffan, A. G.
    Bach, H. -G
    100 Gb/s OOK transmission through 212 km field SSMF using monolithically integrated ETDM receiver module2009Ingår i: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009, 2009, s. 5377273-Konferensbidrag (Refereegranskat)
    Abstract [en]

    100 Gb/s on-off-key transmission over 212 km installed standard single mode fibers using an electrical InP-based clock-data-recovery and 1:2 demultiplexer module was demonstrated. Error-free performance was achieved with 1.1 dB OSNR penalty at 10-9 BER after transmission.

  • 227.
    Wang, Ke
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101). Beijing Institute of Technology, China.
    Li, J.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101).
    Jacobsen, G.
    4x40 GHz multi-colored optical pulse generation using single two-arm modulated mach-zehnder modulator2009Ingår i: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009, 2009, s. 5377278-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Picosecond 4x40 GHz multi-colored optical pulses have been generated using a single two-arm modulated Mach-Zehnder modulator. In the same time the pulses can be aligned in the time domain to form a uniform 160 GHz multi-colored pulse train.

  • 228.
    Wang, Ke
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Li, Jie
    Djupsjobacka, Anders
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Jacobsen, Gunnar
    Makon, Robert Elvis
    Driad, Rachid
    Walcher, Herbert
    Rosenzweig, Josef
    Steffan, Andreas G.
    Mekonnen, G. Giorgis
    Bach, Heinz-Gunter
    Li, Zhuo
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    100 Gb/s RZ-OOK transmission through 212 km deployed SSMF using monolithically integrated ETDM receiver module2011Ingår i: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 284, nr 3, s. 782-786Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    100 Gb/s on-off keying (OOK) transmission over 212 km installed standard single-mode fibers using an Indium Phosphide (InP)-based electrical clock-data-recovery (CDR) and demultiplexer module was demonstrated 5 5 x 10(-11) bit error rate (BER) performance was achieved and 11 dB optical signal-to-noise ratio (OSNR) penalty was required at 10(-9) BER after transmission

  • 229.
    Wyrowski, Frank
    et al.
    University of Jena, Germany.
    Popov, SergeiKTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.Jaroszewicz, ZbigniewInst. of Applied Optics, Warsaw, Poland.
    Optical Security Systems2005Proceedings (redaktörskap) (Övrigt vetenskapligt)
  • 230. Xu, T.
    et al.
    Bayvel, P.
    Liu, T.
    Zhang, Y.
    Jacobsen, G.
    Li, J.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Carrier phase estimation in dispersion-unmanaged optical transmission systems2017Ingår i: Proceedings of 2017 IEEE 2nd Advanced Information Technology, Electronic and Automation Control Conference, IAEAC 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, s. 1860-1864, artikel-id 8054335Konferensbidrag (Refereegranskat)
    Abstract [en]

    The study on carrier phase estimation (CPE) approaches, involving a one-tap normalized least-mean-square (NLMS) algorithm, a block-wise average algorithm, and a Viterbi-Viterbi algorithm has been carried out in the long-haul high-capacity dispersion-unmanaged coherent optical systems. The close-form expressions and analytical predictions for bit-error-rate behaviors in these CPE methods have been analyzed by considering both the laser phase noise and the equalization enhanced phase noise. It is found that the Viterbi-Viterbi algorithm outperforms the one-tap NLMS and the block-wise average algorithms for a small phase noise variance (or effective phase noise variance), while the three CPE methods converge to a similar performance for a large phase noise variance (or effective phase noise variance). In addition, the differences between the three CPE approaches become smaller for higher-level modulation formats.

  • 231. Xu, T.
    et al.
    Jacobsen, Gunnar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik. Acreo Swedish ICT AB, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Liu, T.
    Zhang, Y.
    Bayvel, P.
    Analytical estimation in differential optical transmission systems influenced by equalization enhanced phase noise2016Ingår i: 2016 Progress In Electromagnetics Research Symposium, PIERS 2016 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2016, s. 4844-4848Konferensbidrag (Refereegranskat)
    Abstract [en]

    An analytical model is presented for assessing the performance of the bit-error-rate (BER) in the differential m-level phase shift keying (m-PSK) transmission systems, where the influence of equalization enhanced phase noise (EEPN) has been considered. Theoretical analysis has been carried out in differential quadrature phase shift keying (DQPSK), differential 8-PSK (D8PSK), and differential 16-PSK (D16PSK) optical transmission systems. The influence of EEPN on the BER performance, in term of signal-to-noise ratio (SNR), are investigated for different fiber dispersion, LO laser linewidths, symbol rates, and modulation formats. Our analytical model achieves a good agreement with previously reported EEPN induced BER floors, and can give an accurate prediction for the DQPSK system, and a leading-order approximation for the D8PSK and the D16PSK systems.

  • 232.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Jacobsen, G.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Li, J.
    Sergeyev, S.
    Mitigation of EEPN in long-haul n-PSK coherent transmission system using modified optical pilot carrier2013Ingår i: Asia Communications and Photonics Conference, ACP 2013, Optical Society of America, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present the compensation of the equalization enhanced phase noise (EEPN) in the long-haul n-level phase shift keying (n-PSK) coherent optical transmission system, by employing a scheme of phase modulated optical pilot carrier.

  • 233.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Jacobsen, G.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Li, J.
    Sergeyev, S.
    Zhang, Y.
    Analysis of carrier phase extraction methods in 112-Gbit/s NRZ-PDM-QPSK coherent transmission system2012Ingår i: 2012 Asia Communications And Photonics Conference (ACP), IEEE , 2012, s. AS1C.2-Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a comparative analysis on three carrier phase extraction approaches, including a one-tap normalized least mean square method, a block-average method, and a Viterbi-Viterbi method, in coherent transmission system considering equalization enhanced phase noise.

  • 234.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Jacobsen, G.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Li, J.
    Wang, Ke
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Variable-step-size LMS adaptive filter for digital chromatic dispersion compensation in PDM-QPSK coherent transmission system2009Ingår i: 2009 International Conference on Optical Instruments and Technology: Optical Systems and Modern Optoelectronic Instruments, SPIE - International Society for Optical Engineering, 2009, s. 75062I-Konferensbidrag (Refereegranskat)
    Abstract [en]

    High bit rates optical communication systems pose the challenge of their tolerance to linear and nonlinear fiber impairments. Digital filters in coherent optical receivers can be used to mitigate the chromatic dispersion entirely in the optical transmission system. In this paper, the least mean square adaptive filter has been developed for chromatic equalization in a 112-Gbit/s polarization division multiplexed quadrature phase shift keying coherent optical transmission system established on the VPIphotonics simulation platform. It is found that the chromatic dispersion equalization shows a better performance when a smaller step size is used. However, the smaller step size in least mean square filter will lead to a slower iterative operation to achieve the guaranteed convergence. In order to solve this contradiction, an adaptive filter employing variable-step-size least mean square algorithm is proposed to compensate the chromatic dispersion in the 112-Gbit/s coherent communication system. The variable-step-size least mean square filter could make a compromise and optimization between the chromatic dispersion equalization performance and the algorithm converging speed. Meanwhile, the required tap number and the converged tap weights distribution of the variable-step-size least mean square filter for a certain fiber chromatic dispersion are analyzed and discussed in the investigation of the filter feature.

  • 235.
    Xu, Tianhua
    et al.
    Univ Warwick, Coventry CV4 7AL, W Midlands, England..
    Jacobsen, Gunnar
    RISE Acreo AB, SE-16440 Stockholm, Sweden..
    Li, Jie
    RISE Acreo AB, SE-16440 Stockholm, Sweden..
    Leeson, Mark
    Univ Warwick, Coventry CV4 7AL, W Midlands, England..
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Dynamic physical layer equalization in optical communication networks2018Ingår i: Optoelectronics and Advanced Materials Rapid Communications, ISSN 1842-6573, E-ISSN 2065-3824, Vol. 12, nr 5-6, s. 292-298Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In optical transport networks, signal lightpaths between two terminal nodes can be different due to current network conditions. Thus the transmission distance and accumulated dispersion in the lightpath cannot be predicted. Therefore, the adaptive compensation of dynamic dispersion is necessary in such networks to enable flexible routing and switching. In this paper, we present a detailed analysis on the adaptive dispersion compensation using the least-mean-square (LMS) algorithm in coherent optical communication networks. It is found that the variable-step-size LMS equalizer can achieve the same performance with a lower complexity, compared to the traditional LMS algorithm.

  • 236.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Jacobsen, Gunnar
    Acreo AB, Electrum 236, Kista, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Forzati, M.
    Acreo AB, Electrum 236, Kista, Sweden.
    Mårtensson, J.
    Acreo AB, Electrum 236, Kista, Sweden.
    Mussolin, M.
    University of Padova, Italy.
    Li, J.
    Acreo AB, Electrum 236, Kista, Sweden.
    Wang, Ke
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Zhang, Y.
    Tianjin University, Tianjin, China.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Frequency-domain chromatic dispersion equalization using overlap-add methods in coherent optical system2011Ingår i: Journal of optical communications, ISSN 0173-4911, E-ISSN 2191-6322, Vol. 27, nr 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The frequency domain equalizers (FDEs) employing two types of overlap-add zero-padding (OLA-ZP) methods are applied to compensate the chromatic dispersion in a 112-Gbit/s non-return-to-zero polarization division multiplexed quadrature phase shift keying (NRZ-PDM-QPSK) coherent optical transmission system. Simulation results demonstrate that the OLA-ZP methods can achieve the same acceptable performance as the overlap-save method. The required minimum overlap (or zero-padding) in the FDE is derived, and the optimum fast Fourier transform length to minimize the computational complexity is also analyzed.

     

  • 237.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Jacobsen, Gunnar
    Acreo AB.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Friberg, Ari
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Li, Jie
    Acreo AB.
    Zhang, Yimo
    Phase noise mitigation in coherent transmission system using a pilot carrier2011Ingår i: Optical Transmission Systems, Subsystems, and Technologies IX / [ed] Xiang Liu, SPIE - International Society for Optical Engineering, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we investigate the phase noise elimination employing an optical pilot carrier in the high speed coherent transmission system considering the equalization enhanced phase noise (EEPN). The numerical simulations are performed in a 28-Gsymbol/s quadrature phase shift keying (QPSK) coherent system with a polarization multiplexed pilot carrier. The carrier phase estimation is implemented by the one-tap normalized least mean square (NLMS) filter and the differential phase detection, respectively. Simulation results demonstrate that the application of the optical pilot carrier is very effective for the intrinsic laser phase noise cancellation, while is less efficient for the EEPN mitigation.

  • 238. Xu, Tianhua
    et al.
    Jacobsen, Gunnar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Li, J.
    Sergeyev, S.
    Friberg, Ari T.
    Liu, T.
    Zhang, Y.
    Analysis of chromatic dispersion compensation and carrier phase recovery in long-haul optical transmission system influenced by equalization enhanced phase noise2017Ingår i: Optik (Stuttgart), ISSN 0030-4026, E-ISSN 1618-1336, Vol. 138, s. 494-508Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The performance of long-haul coherent optical fiber transmission system is significantly affected by the equalization enhanced phase noise (EEPN), due to the interaction between the electronic dispersion compensation (EDC) and the laser phase noise. In this paper, we present a comprehensive study on different chromatic dispersion (CD) compensation and carrier phase recovery (CPR) approaches, in the n-level phase shift keying (n-PSK) and the n-level quadrature amplitude modulation (n-QAM) coherent optical transmission systems, considering the impacts of EEPN. Four CD compensation methods are considered: the time-domain equalization (TDE), the frequency-domain equalization (FDE), the least mean square (LMS) adaptive equalization are applied for EDC, and the dispersion compensating fiber (DCF) is employed for optical dispersion compensation (ODC). Meanwhile, three carrier phase recovery methods are also involved: a one-tap normalized least mean square (NLMS) algorithm, a block-wise average (BWA) algorithm, and a Viterbi-Viterbi (VV) algorithm. Numerical simulations have been carried out in a 28-Gbaud dual-polarization quadrature phase shift keying (DP-QPSK) coherent transmission system, and the results indicate that the origin of EEPN depends on the choice of chromatic dispersion compensation methods, and the effects of EEPN also behave moderately different in accordance to different carrier phase recovery scenarios.

  • 239.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101). Acreo AB, Sweden.
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Li, J.
    Wang, Ke
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101). Acreo AB, Sweden.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Digital compensation of chromatic dispersion in 112-Gbit/s PDM-QPSK system2009Ingår i: Optical Transmission Systems, Switching, and Subsystems VII, SPIE - International Society for Optical Engineering, 2009, s. 763202-Konferensbidrag (Refereegranskat)
    Abstract [en]

    High bit rates optical communication systems pose the challenge of their tolerance to linear and nonlinear fiber impairments. Coherent optical receivers using digital signal processing techniques can mitigate the fiber impairments in the optical transmission system, including the chromatic dispersion equalization with digital filters. In this paper, an adaptive finite impulse response filter employing normalized least mean square algorithm is developed for compensating the chromatic dispersion in a 112-Gbit/s polarization division multiplexed quadrature phase shift keying coherent communication system, which is established in the VPI simulation platform. The principle of the adaptive normalized least mean square algorithm for signal equalization is analyzed theoretically, and at the meanwhile, the taps number and the tap weights in the adaptive finite impulse response filter for compensating a certain fiber chromatic dispersion are also investigated by numerical simulation. The chromatic dispersion compensation performance of the adaptive filter is analyzed by evaluating the behavior of the bitor-rate versus the optical signal-to-noise ratio, and the compensation results are also compared with other present digital filters.

  • 240.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Jacobsen, Gunnar
    Acreo AB, Electrum 236, Kista, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Li, Jie
    Acreo AB, Electrum 236, Kista, Sweden.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Zhang, Yimo
    Tianjin University, China.
    Analytical estimation of phase noise influence in coherent transmission system with digital dispersion equalization2011Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 19, nr 8, s. 7756-7768Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a novel investigation on the enhancement of phase noise in coherent optical transmission system due to electronic chromatic dispersion compensation. Two types of equalizers, including a time domain fiber dispersion finite impulse response (FD-FIR) filter and a frequency domain blind look-up (BLU) filter are applied to mitigate the chromatic dispersion in a 112-Gbit/s polarization division multiplexed quadrature phase shift keying (PDM-QPSK) transmission system. The bit-error-rate (BER) floor in phase estimation using an optimized one-tap normalized least-mean-square (NLMS) filter, and considering the equalization enhanced phase noise (EEPN) is evaluated analytically including the correlation effects. The numerical simulations are implemented and compared with the performance of differential QPSK demodulation system. (C) 2011 Optical Society of America

  • 241.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Li, Jie
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Zhang, Yimo
    Carrier phase estimation methods in coherent transmission systems influenced by equalization enhanced phase noise2013Ingår i: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 293, s. 54-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a comparative study on three carrier phase estimation algorithms, including a one-tap normalized least mean square (NLMS) method, a block-average method, and a Viterbi-Viterbi method in the n-level phase shift keying coherent transmission systems considering the equalization enhanced phase noise (EEPN). In these carrier phase estimation methods, the theoretical bit-error-rate floors based on traditional leading-order Taylor expansion are compared to the practical simulation results, and the tolerable total effective linewidths (involving the transmitter, the local oscillator lasers and the EEPN) for a fixed bit-error-rate floor are evaluated with different block sizes, when the fiber nonlinearities are neglected. The complexity of the three carrier phase estimation methods is also discussed. We find that the carrier phase estimation methods in practical systems should be analyzed based on the simulation results rather than the traditional theoretical predictions, when large EEPN is involved. The one-tap NLMS method can always show an acceptable behavior, while the step size is complicated to optimize. The block-average method is efficient to implement, but it behaves unsatisfactorily when using a large block size. The Viterbi-Viterbi method can show a small improvement compared to the block-average method, while it requires more computational complexity.

  • 242.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Jacobsen, Gunnar
    Acreo AB, Electrum 236, Kista, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Li, Jie
    Acreo AB, Electrum 236, Kista, Sweden.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Zhang, Yimo
    Tianjin University, China.
    Digital chromatic dispersion compensation in coherent transmission system using a time-domain filter2010Ingår i: 2010 Asia Communications and Photonics Conference and Exhibition, ACP 2010, Shanghai, 2010, s. 132-133Konferensbidrag (Refereegranskat)
    Abstract [en]

    We demonstrate the chromatic dispersion equalization employing a time-domain filter in a 112-Gbit/s polarization division multiplexed quadrature phase shift keying coherent system. The required tap number of the filter is analyzed from anti-aliasing and pulse broadening. The dynamic range of the filter is evaluated by using different number of taps. ©2010 IEEE.

  • 243. Xu, Tianhua
    et al.
    Jacobsen, Gunnar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Li, Jie
    Liu, Tiegen
    Zhang, Yimo
    Close-Form Expression of One-Tap Normalized LMS Carrier Phase Recovery in Optical Communication Systems2016Ingår i: FOURTH INTERNATIONAL CONFERENCE ON WIRELESS AND OPTICAL COMMUNICATIONS, SPIE , 2016, artikel-id UNSP 990203Konferensbidrag (Refereegranskat)
    Abstract [en]

    The performance of long-haul high speed coherent optical fiber communication systems is significantly degraded by the laser phase noise and the equalization enhanced phase noise (EEPN). In this paper, the analysis of the one-tap normalized least-mean-square (LMS) carrier phase recovery (CPR) is carried out and the close-form expression is investigated for quadrature phase shift keying (QPSK) coherent optical fiber communication systems, in compensating both laser phase noise and equalization enhanced phase noise. Numerical simulations have also been implemented to verify the theoretical analysis. It is found that the one-tap normalized least-mean-square algorithm gives the same analytical expression for predicting CPR bit-error-rate (BER) floors as the traditional differential carrier phase recovery, when both the laser phase noise and the equalization enhanced phase noise are taken into account.

  • 244. Xu, Tianhua
    et al.
    Jacobsen, Gunnar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik. Acreo Swedish ICT AB, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Li, Jie
    Liu, Tiegen
    Zhang, Yimo
    Bayvel, Polina
    Analytical Investigations on Carrier Phase Recovery in Dispersion-Unmanaged n-PSK Coherent Optical Communication Systems2016Ingår i: PHOTONICS, ISSN 2304-6732, Vol. 3, nr 4, artikel-id 51Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using coherent optical detection and digital signal processing, laser phase noise and equalization enhanced phase noise can be effectively mitigated using the feed-forward and feed-back carrier phase recovery approaches. In this paper, theoretical analyses of feed-back and feed-forward carrier phase recovery methods have been carried out in the long-haul high-speed n-level phase shift keying (n-PSK) optical fiber communication systems, involving a one-tap normalized least-mean-square (LMS) algorithm, a block-wise average algorithm, and a Viterbi-Viterbi algorithm. The analytical expressions for evaluating the estimated carrier phase and for predicting the bit-error-rate (BER) performance (such as the BER floors) have been presented and discussed in the n-PSK coherent optical transmission systems by considering both the laser phase noise and the equalization enhanced phase noise. The results indicate that the Viterbi-Viterbi carrier phase recovery algorithm outperforms the one-tap normalized LMS and the block-wise average algorithms for small phase noise variance (or effective phase noise variance), while the one-tap normalized LMS algorithm shows a better performance than the other two algorithms for large phase noise variance (or effective phase noise variance). In addition, the one-tap normalized LMS algorithm is more sensitive to the level of modulation formats.

  • 245.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO. Tianjin University, Peoples R China; UCL, England.
    Jacobsen, Gunnar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO. Acreo Swedish ICT AB, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Li, Jie
    Sergeyev, Sergey
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Zhang, Yimo
    Analytical BER performance in differential n-PSK coherent transmission system influenced by equalization enhanced phase noise2015Ingår i: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 334, s. 222-227Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Long haul high speed optical transmission systems are significantly distorted by the interplay between the electronic chromatic dispersion (CD) equalization and the local oscillator (LO) laser phase noise, which leads to an effect of equalization enhanced phase noise (EEPN). The EEPN degrades the performance of optical communication systems severely with the increment of fiber dispersion. LO laser linewidth, symbol rare, and modulation format. In this paper, we present an analytical model for evaluating the performance of bit-error-rate (BER) versus signal-to-noise ratio (SNR) in the n-level phase shift keying (n-PSK) coherent transmission system employing differential carrier phase estimation (CPE), where the influence of EEPN is considered. Theoretical results based on this model have been investigated for the differential quadrature phase shift keying (DQPSK). the differential 8-PSK (D8PSK), and the differential 16-PSK (D16PSK) coherent transmission systems. The influence of EEPN on the BER performance in term of the fiber dispersion, the LO phase noise, the symbol rate, and the modulation format are analyzed in detail. The BER behaviors based on this analytical model achieve a good agreement with previously reported BER floors influenced by EEPN. Further simulations have also been carried out in the differential CPE considering EEPN. The results indicate that this analytical model can give an accurate prediction for the DQPSK system, and a leading-order approximation for the D8PSK and the D16PSK systems.

  • 246.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Li, Jie
    Sergeyev, Sergey
    Zhang, Yimo
    Influence of Digital Dispersion Equalization on Phase Noise Enhancement in Coherent Optical System2012Ingår i: 2012 Asia Communications And Photonics Conference (ACP), IEEE , 2012, s. AS1C.3-Konferensbidrag (Refereegranskat)
    Abstract [en]

    The phase noise enhancement due to digital dispersion equalization is investigated, which indicates that the phase noise from transmitter laser can also interact with the dispersion depending on the choice of digital dispersion compensation methods.

  • 247.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Jacobsen, Gunnar
    Acreo AB, Electrum 236, Kista, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Li, Jie
    Acreo AB, Electrum 236, Kista, Sweden.
    Vanin, Evgeny
    Acreo AB, Electrum 236, Kista, Sweden.
    Wang, Ke
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Zhang, Yimo
    Tianjin University, China.
    Chromatic dispersion compensation in coherent transmission system using digital filters2010Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 18, nr 15, s. 16243-16257Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a comparative analysis of three popular digital filters for chromatic dispersion compensation: a time-domain least mean square adaptive filter, a time-domain fiber dispersion finite impulse response filter, and a frequency-domain blind look-up filter. The filters are applied to equalize the chromatic dispersion in a 112-Gbit/s non-return-to-zero polarization division multiplexed quadrature phase shift keying transmission system. The characteristics of these filters are compared by evaluating their applicability for different fiber lengths, their usability for dispersion perturbations, and their computational complexity. In addition, the phase noise tolerance of these filters is also analyzed. (C) 2010 Optical Society of America

  • 248.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Jacobsen, Gunnar
    Acreo AB, Electrum 236, Kista, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Li, Jie
    Acreo AB, Electrum 236, Kista, Sweden.
    Wang, Ke
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Digital compensation of chromatic dispersion in 112-Gbit/s PDM-QPSK system2009Ingår i: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009, 2009, s. 5377275-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Coherent optical receivers with digital filters can mitigate the impairments in optical transmission system. In this paper, an adaptive filter employing NLMS algorithm is developed for chromatic dispersion compensation in a 112-Gbit/s PDM-QPSK coherent communication system. The performance of the adaptive filter is analyzed by comparing with present digital filters .

  • 249.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Jacobsen, Gunnar
    Acreo AB, Electrum 236, Kista, Sweden.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Li, Jie
    Acreo AB, Electrum 236, Kista, Sweden.
    Wang, Ke
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Normalized LMS digital filter for chromatic dispersion equalization in 112-Gbit/s PDM-QPSK coherent optical transmission system2010Ingår i: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 283, nr 6, s. 963-967Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High bit rates optical communication systems pose the challenge of their tolerance to linear and nonlinear fiber impairments. Coherent optical receivers using digital signal processing techniques can mitigate the fiber impairments in the optical transmission system, including the chromatic dispersion equalization with digital filters. In this paper, an adaptive finite impulse response filter employing normalized least mean square algorithm is developed for compensating the chromatic dispersion in a 112-Gbit/s polarization division multiplexed quadrature phase shift keying coherent communication system, which is established in the VPI Simulation platform. The principle of the adaptive normalized least mean square algorithm for signal equalization is analyzed theoretically, and at the meanwhile, the taps number and the tap weights in the adaptive finite impulse response filter for compensating a certain fiber chromatic dispersion are also investigated by numerical simulation. The chromatic dispersion compensation performance of the adaptive filter is analyzed by evaluating the behavior of the bit-error-rate versus the optical signal-to-noise ratio, and the compensation results are also compared with other present digital filters.

  • 250.
    Xu, Tianhua
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Li, J.
    Djupsjöbacka, A.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Jacobsen, G.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Quasi real-time 230-Gbit/s coherent transmission field trial over 820 km SSMF using 57.5-Gbaud dual-polarization QPSK2013Ingår i: Asia Communications and Photonics Conference, ACP 2013, Optical Society of America, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    We demonstrate 230-Gbit/s (57.5-Gbaud) polarization-multiplexed QPSK coherent transmission over 820 km field-installed SSMF with quasi real-time DSP, without resorting to ETDM. BER performance well below FEC error-free threshold (2×10-3) at 231-1 PRBS length was achieved.

23456 201 - 250 av 269
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