Change search
Refine search result
1234 101 - 150 of 191
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101. Morthier, G.
    et al.
    Baets, R.
    Tsang, C. F.
    Caroll, J. E.
    Wenzel, H.
    Mecozzi, A.
    Sapia, A.
    Correc, P.
    Hansmann, S.
    Burkhardt, H.
    Bonello, R.
    Montrosset, I.
    Lassen, H. E.
    Olesen, H.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Bissessur, H.
    Vey, J-L
    Duan, G.
    Comparison of different DFB laser models within the European COST 240 collaboration1993In: Integrated Photonics Research (IPR) Palm Springs, California March 22, 1993    Semiconductor Device Modeling 1 (IWB), 1993Conference paper (Refereed)
  • 102. Morthier, G.
    et al.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Extended modulation bandwidth of DBR and external cavity lasers by utilizing a cavity resonance for equalization2000In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 36, no 12, p. 1468-1475Article in journal (Refereed)
    Abstract [en]

    We have investigated the occurence of a second resonance frequency in distributed Bragg reflector laser diodes and the high modulation bandwidth resulting from it. The influence of different laser parameters has been theoretically investigated. It is also shown that a similar behavior can be obtained in laser diodes with a passive, low-loss, and gratingless external cavity, The possibilities of large-signal digital modulation are also investigated.

  • 103. Morthier, G.
    et al.
    Verhoeve, P.
    Baets, R.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Extraction of a large set of laser parameters from different measurements1996In: Semiconductor Laser Conference, 1996., 15th IEEE International, 1996, p. 175-176Conference paper (Refereed)
    Abstract [en]

    We show how most of the parameters of a DFB laser can be extracted from a limited number of relatively simple measurements. These measurements include the ASE spectra at different currents below threshold, the RIN spectra above threshold and the P-I relation. We have performed curve-fitting on different characteristics such as the ASE spectrum, the RIN spectrum and the P-I curve. From the ASE spectrum measured in the vicinity of the lasing wavelength we can extract grating parameters, facet phases, refractive index and gain as well as the wavelength and current dependence of the last two parameters

  • 104. Morthier, Geert
    et al.
    Baets, Roel
    TSIGOPOULOS, A
    SPHICOPOULOS, T
    TSANG, CF
    CARROLL, JE
    WENZEL, H
    MECOZZI, A
    SAPIA, A
    CORREC, P
    HANSMANN, S
    BURKHARD, H
    PARADISI, A
    MONTROSSET, I
    OLESEN, H
    LASSEN, HE
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    BISSESSUR, H
    COMPARISON OF DIFFERENT DFB LASER MODELS WITHIN THE EUROPEAN COST-240 COLLABORATION.1994In: IEE Proceedings - Optoelectronics, ISSN 1350-2433, E-ISSN 1359-7078, Vol. 141, p. 82-88Article in journal (Refereed)
  • 105. Navarro, J. R.
    et al.
    Olmedo, Miguel Iglesias
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Pang, Xiaodan
    RISE ACREO AB.
    Ozolins, O.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, G.
    Popov, Sergei Yu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zibar, D.
    Phase noise tolerant carrier recovery scheme for 28 Gbaud circular 16QAM2015In: European Conference on Optical Communication, ECOC, Institute of Electrical and Electronics Engineers (IEEE), 2015Conference paper (Refereed)
    Abstract [en]

    We propose a novel carrier phase recovery scheme for circular 16QAM coherent transmission systems. Experimental results show low penalties (<1.4 dB) even for linewidths where square 16QAM exhibits irretrievable (above the FEC limit) error floor.

  • 106. Navarro, J. R.
    et al.
    Udalcovs, A.
    Pang, Xiaodan
    KTH, School of Information and Communication Technology (ICT).
    Ozolins, O.
    Kakkar, Aditya
    KTH, School of Engineering Sciences (SCI).
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI).
    Nordwall, F.
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Jacobsen, G.
    High phase noise tolerant circular-64QAM with efficient phase recovery for coherent optical systems2017In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2017Conference paper (Refereed)
    Abstract [en]

    We experimentally demonstrate the significant phase noise tolerance increase of 28Gbaud circular-64QAM constellations against its square-64QAM counterpart with a novel, low complexity and high-performance phase recovery scheme employing only 8 test phases.

  • 107. Navarro, Jaime Rodrigo
    et al.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Pang, Xiaodan
    Olmedo, Miguel Iglesias
    KTH.
    Ozolins, Oskars
    Da Ros, Francesco
    Piels, Molly
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Zibar, Darko
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Two-Stage n-PSK Partitioning Carrier Phase Recovery Scheme for Circular mQAM Coherent Optical Systems2016In: PHOTONICS, ISSN 2304-6732, Vol. 3, no 2, article id 37Article in journal (Refereed)
    Abstract [en]

    A novel two-stage n-PSK partitioning carrier phase recovery (CPR) scheme for circular multilevel quadrature amplitude modulation (C-mQAM) constellations is presented. The first stage of the algorithm provides an initial rough estimation of the received constellation, which is utilized in the second stage for CPR. The performance of the proposed algorithm is studied through extensive simulations at the forward error correction bit error rate targets of 3.8 x 10(-3) and 1 x 10(-2) and is compared with different CPR algorithms. A significant improvement in the combined linewidth symbol duration product (Delta vT(s)) tolerance is achieved compared to the single-stage n-PSK partitioning scheme. Superior performance in the Delta vT(s) tolerance compared to the blind phase search algorithm is also reported. The relative improvements with respect to other CPR schemes are also validated experimentally for a 28-Gbaud C-16QAM back-to-back transmission system. The computational complexity of the proposed CPR scheme is studied, and reduction factors of 24.5 broken vertical bar 30.1 and 59.1 broken vertical bar 63.3 are achieved for C-16QAM and C-64QAM, respectively, compared to single-stage BPS in the form of multipliers broken vertical bar adders.

  • 108. Navarro, Jaime Rodrigo
    et al.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Pang, Xiaodan
    Ozolins, Oskars
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Olmedo, Miguel Iglesias
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Carrier Phase Recovery Algorithms for Coherent Optical Circular mQAM Systems2016In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 34, no 11, p. 2717-2723Article in journal (Refereed)
    Abstract [en]

    The phase noise tolerance of circular multilevel quadrature amplitude modulation (C-mQAM) constellations employing different carrier phase recovery (CPR) algorithms is studied. A differential decoding scheme and a bit mapping for this type of constellations are proposed. A novel CPR scheme for C-mQAM constellations is also presented. The particular distribution of the constellation points in a C-mQAM signal is exploited to reduce the required Nth power for the removal of the modulation component by a factor of two. Hence, the computational complexity of the proposed algorithm is drastically reduced. The combined linewidth symbol duration product (Delta nu T-s) tolerance of different CPR algorithms for C-mQAM constellations is studied and compared with the proposed CPR scheme. The results are analyzed at 3.8e-3 and 1e-2 bit error rate forward error correction limits. The proposed CPR scheme achieves similar Delta nu Ts tolerance compared to single stage BPS algorithm while its computational complexity is reduced by group factors of 27.2 vertical bar 32.3, and 30.5 vertical bar 32.6 (in the form of multipliers vertical bar adders) for C-16QAM and C-64QAM, respectively.

  • 109. Nilsson, S.
    et al.
    Kjellberg, T.
    Klinga, T.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wallin, J.
    Streubel, K.
    Improved spectral characteristics of MQW-DFB lasers by incorporation of multiple phase-shifts1995In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 13, p. 434-441Article in journal (Refereed)
    Abstract [en]

    The single-mode stability of strained-layer MQW-DFB lasers with electron-beam written gratings containing zero, one and three phase-shifts, and with a relatively large coupling strength, has been investigated theoretically and experimentally. The fabricated lasers with the multiple phase-shifted (MPS) structure exhibited a higher degree of stability than the lambda;/4-shifted lasers, and a considerably improved stability for both categories with phase-shifts compared to the nonshifted lasers was obtained. These results were in good agreement with our simulations. An investigation of the linewidths of the phase-shifted lasers is also presented. The MPS lasers had a significantly lower linewidth floor (down to 600 kHz) than those with one phase-shift. There was no degradation of the side-mode suppression-ratio correlated to the linewidth floor or rebroadening. A possible explanation for the lower linewidth floors obtained for the MPS lasers is that this structure is less sensitive to inhomogeneous carrier fluctuations. Longitudinal fluctuations in the shape of the photon density distribution will thereby be suppressed

  • 110.
    Nilsson, S.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kjellberg, T.
    Klinga, T.
    Wallin, J.
    Streubel, K.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    DFB laser with nonuniform coupling coefficient realized by double-layer buried grating1993In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 5, p. 1128-1131Article in journal (Refereed)
    Abstract [en]

    A technique for the realization of a nonuniform grating coupling coefficient kappa , and its implementation in distributed-feedback (DFB) lasers is presented. This technique, which is an extension of the buried-grating concept, offers precise control of the coupling coefficient and enables a kappa -ratio greater than 10. DFB lasers with an asymmetric kappa -variation have been fabricated using this method. A front-to-rear facet output power ratio close to five was obtained, qualitatively in agreement with simulations.<>

  • 111.
    Olmedo, Miguel Iglesias
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Technical University of Denmark (DTU), Denmark.
    Pang, Xiaodan
    RISE ACREO AB; Technical University of Denmark (DTU).
    Piels, M.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Acreo AB, Sweden.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Monroy, I. T.
    Zibar, D.
    Carrier recovery techniques for semiconductor laser frequency noise for 28 Gbd DP-16QAM2015In: Optical Fiber Communication Conference, OFC 2015, IEEE , 2015Conference paper (Refereed)
    Abstract [en]

    We report on the first experimental comparison of DD-PLL, two-stage feed forward, and two variations of extended Kalman filtering for tracking semiconductor laser frequency noise. We identify which carrier phase recovery technique works best depending on the carrier induced frequency noise profile.

  • 112.
    Olmedo, Miguel Iglesias
    et al.
    KTH. VPI Photon GmBH, Germany.
    Pang, Xiaodan
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Ozolins, Oskars
    Louchet, Hadrien
    Zibar, Darko
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI. Acreo Swedish ICT AB, Sweden.
    Monroy, Idelfonso Tafur
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Effective Linewidth of Semiconductor Lasers for Coherent Optical Data Links2016In: PHOTONICS, ISSN 2304-6732, Vol. 3, no 2, article id 39Article in journal (Refereed)
    Abstract [en]

    We discuss the implications of using monolithically integrated semiconductor lasers in high capacity optical coherent links suitable for metro applications, where the integration capabilities of semiconductor lasers make them an attractive candidate to reduce transceiver cost. By investigating semiconductor laser frequency noise profiles we show that carrier induced frequency noise plays an important role in system performance. We point out that, when such lasers are employed, the commonly used laser linewidth fails to estimate systemperformance, and we propose an alternative figure of merit that we name "Effective Linewidth". We derive this figure of merit analytically, explore it by numerical simulations and experimentally validate our results by transmitting a 28 Gbaud DP-16QAM over an optical link. Our investigations cover the use of semiconductor lasers both in the transmitter side and as a local oscillator at the receiver. The obtained results show that our proposed "effective linewidth" is easy to measure and accounts for frequency noise more accurately, and hence the penalties associated to phase noise in the received signal.

  • 113.
    Olmedo, Miguel Iglesias
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Technical University of Denmark (DTU), Denmark .
    Pang, Xiaodan
    Acreo AB, Sweden.
    Udalcovs, Aleksejs
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Riga Technical University, Latvia .
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zibar, D.
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Networking and Transmission Laboratory, Sweden .
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Monroy, I. T.
    Impact of carrier induced frequency noise from the transmitter laser on 28 and 56 gbaud DP-QPSK metro links2014In: Asia Communications and Photonics Conference, ACPC 2014, Optical Society of America, 2014Conference paper (Refereed)
    Abstract [en]

    We experimentally evaluate the robustness of 28/56 Gbaud DP-QPSK against semiconductor laser frequency noise for cost-efficient 200 Gbps metropolitan links and derive the laser specification guidelines for successful transmission over 500 km SSMF.

  • 114.
    Omanakuttan, Giriprasanth
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Sun, Yan-Ting
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Reuterskiöld-Hedlund, Carl
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics, Integrated devices and circuits.
    Junesand, Carl
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Lourdudoss, Sebastian
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Paillard, Valerie
    Almae Technologies.
    Lelarge, François
    Almae Technologies.
    Browne, Jack
    Tyndall National Institute.
    Justice, John
    Tyndall National Institute.
    Corbett, Brian
    Tyndall National Institute.
    Electrically pumped 1.5 μm gain material on InP/SiManuscript (preprint) (Other academic)
  • 115. Ozolins, O.
    et al.
    Pang, Xiaodan
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Udalcovs, A.
    Lin, Rui
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Van Kerrebrouck, J.
    Gan, L.
    Zhang, Lu
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tang, M.
    Fu, S.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Westergren, Urban
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Jacobsen, G.
    Liu, D.
    Tong, W.
    Torfs, G.
    Bauwelinck, J.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Yin, X.
    7×149 Gbit/s PAM4 transmission over 1 km multicore fiber for short-reach optical interconnects2018In: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2018Conference paper (Refereed)
    Abstract [en]

    We transmit 80 Gbaud/λ/core PAM4 signal enabled by 1.55 μm EML over 1 km 7-core fiber. The solution achieves single-wavelength and single-fiber 1.04 Tbit/s post-FEC transmission enhancing bandwidth-density for short-reach optical interconnects.

  • 116.
    Ozolins, O.
    et al.
    RISE Acreo, Kista, Sweden..
    Pang, Xiaodan
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo, Kista, Sweden.
    Udalcovs, A.
    RISE Acreo, Kista, Sweden..
    Zhang, Lu
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Westergren, Urban
    Jacobsen, G.
    RISE Acreo, Kista, Sweden..
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Short Reach Optical Interconnects with Single Externally Modulated Laser Operated in C-Band2018In: 2018 20TH ANNIVERSARY INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON) / [ed] Jaworski, M Marciniak, M, Institute of Electrical and Electronics Engineers (IEEE), 2018Conference paper (Refereed)
  • 117. Ozolins, O.
    et al.
    Udalcovs, A.
    Pang, Xiaodan
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Lin, Rui
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Djupsjöbacka, A.
    Mårtensson, J.
    Fröjdh, K.
    Gan, L.
    Tang, M.
    Fu, S.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Westergren, Urban
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Liu, D.
    Tong, W.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Jacobsen, G.
    112 Gbps/λ PAM4 inter-DCI with continuous-fiber Bragg grating based dispersion compensators2018In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2018Conference paper (Refereed)
    Abstract [en]

    We demonstrate 56 Gbaud/λ PAM4 inter - data center interconnects over 81 km single core single mode fiber and 33.6 km 7-core single mode fiber with continuous-fiber Bragg grating based chromatic dispersion compensators covering C-band.

  • 118. Ozolins, Oskars
    et al.
    Pang, Xiaodan
    Iglesias Olmedo, Miguel
    KTH, School of Information and Communication Technology (ICT).
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT).
    Udalcovs, Aleksejs
    Gaiarin, Simone
    KTH, School of Information and Communication Technology (ICT).
    Navarro, Jaime Rodrigo
    Engenhardt, Klaus M.
    Asyngier, Tadeusz
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT).
    Li, Jie
    Nordwall, Fredrik
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT).
    Zibar, Darko
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT).
    Jacobsen, Gunnar
    100 GHz Externally Modulated Laser for Optical Interconnects2017In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 35, no 6, p. 1174-1179Article in journal (Refereed)
    Abstract [en]

    We report on a 116 Gb/s on-off keying (OOK), four pulse amplitude modulation (PAM) and 105-Gb/s 8-PAM optical transmitter using an InP-based integrated and packaged externally modulated laser for high-speed optical interconnects with up to 30 dB static extinction ratio and over 100-GHz 3-dB bandwidth with 2 dB ripple. In addition, we study the tradeoff between power penalty and equalizer length to foresee transmission distances with standard single mode fiber.

  • 119.
    Ozolins, Oskars
    et al.
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Pang, Xiaodan
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden.;KTH Royal Inst Technol, Sch ICT, Stockholm, Sweden.;KTH Royal Inst Technol, Sch SCI, Stockholm, Sweden..
    Udalcovs, Aleksejs
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Westergren, Urban
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Rodrigo Navarro, Jaime
    Kakkar, Aditya
    KTH.
    Nordwall, Fredrik
    Tektronix AB, Stockholm, Sweden..
    Engenhardt, Klaus M.
    Tektronix GmbH, Stuttgart, Germany..
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Jacobsen, Gunnar
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    100 Gbaud 4PAM Link for High Speed Optical Interconnects2017In: 43RD EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC 2017), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    We demonstrate 100 Gbaud 4PAM transmission over 400 meters SMF with monolithically integrated 1550 nm DFB-TWEAM having 100 GHz 3-dB bandwidth with 2 dB ripple. We evaluate its capabilities to enable two lanes 400 GbE client-side links for optical interconnects.

  • 120.
    Pang, Xiaodan
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, O.
    RISE Acreo AB, NETLAB Networking & Transmiss Lab, Isafjordsgatan 22, S-16440 Kista, Sweden..
    Navarro, Julien R. G.
    Udalcovs, A.
    RISE Acreo AB, NETLAB Networking & Transmiss Lab, Isafjordsgatan 22, S-16440 Kista, Sweden..
    Kakkar, Aditya
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Lin, Rui
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics. KTH Royal Inst Technol, Isafjordsgatan 22, S-16440 Kista, Sweden..
    Tang, M.
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Fu, S.
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Liu, D.
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Jacobsen, G.
    RISE Acreo AB, NETLAB Networking & Transmiss Lab, Isafjordsgatan 22, S-16440 Kista, Sweden..
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Low-Complexity Digital Signal Processing Techniques to Enable Coherent Optical Systems for Metro and Access networks2018In: 23RD OPTO-ELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC2018), IEEE , 2018Conference paper (Refereed)
    Abstract [en]

    We summarize our recent research works on enabling coherent optical transmission systems for metro and access networks with low-complexity digital signal processing techniques, focusing on reduction of laser linewidth requirement with efficient carrier phase recovery.

  • 121.
    Pang, Xiaodan
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, O.
    Zhang, L.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Udalcovs, A.
    Storck, Joakim
    KTH.
    Maisons, G.
    Carras, M.
    Xiao, S.
    Jacobsen, G.
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Lourdudoss, Sebastian
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    4 Gbps PAM-4 and DMT Free Space Transmission using a 4.65-pm Quantum Cascaded Laser at Room Temperature2017In: European Conference on Optical Communication, ECOC, Institute of Electrical and Electronics Engineers Inc. , 2017, p. 1-3Conference paper (Refereed)
    Abstract [en]

    We experimentally demonstrate 4Gbps PAM-4 and DMT transmissions using a quantum cascaded laser (QCL) emitting at mid-wavelength infrared of 4.65μm and a commercial infrared photovoltaic detector. The QCL is directly modulated and operated at room temperature with Peltier Cooling. 

  • 122.
    Pang, Xiaodan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, Oscar
    Gaiarin, S.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Rodrigo Navarro, J.
    Iglesias Olmedo, M.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Udalcovs, A.
    Westergren, U.
    Zibar, D.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Experimental Study of 1.55-μ m EML-Based Optical IM/DD PAM-4/8 Short Reach Systems2017In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 29, no 6, p. 523-526, article id 7839925Article in journal (Refereed)
    Abstract [en]

    We experimentally evaluate high-speed intensity modulation/direct detection (IM/DD) transmissions with a 1.55-μ text broadband electro-Absorption modulated laser and pulse amplitude modulations (PAM). We demonstrate 80 Gb/s/ λ PAM-4 and 96 Gb/s/ λ PAM-8 transmissions with low-complexity digital equalizers at the receiver. Performance comparison with different types of equalizers are performed, including linear symbol-spaced feed-forward equalizer (FFE), fractional (half-symbol) spaced FFE and decision feedback equalizer (DFE), with different tap number. It is found that for both cases, a 6-Tap symbol-spaced FFE is sufficient to achieve a stable performance with bit-error-rate below the 7% overhead hard decision forward error correction (7%-OH HD-FEC) threshold over a 4 km standard single mode fiber link. Practical considerations including comparison between adaptive and static equalizer implementation and tolerable fiber chromatic dispersion are discussed.

  • 123.
    Pang, Xiaodan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Ozolins, Oskars
    El-Taher, Atalla
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Jacobsen, Gunnar
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Sergeyev, Sergey
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Experimental Evaluation of Impairments in Unrepeatered DP-16QAM Link with Distributed Raman Amplification2017In: PHOTONICS, ISSN 2304-6732, Vol. 4, no 1, article id 16Article in journal (Refereed)
    Abstract [en]

    The transmission impairments of a Raman amplified link using dual-polarization 16-quadrature amplitude modulation (DP-16QAM) are experimentally characterized. The impact of amplitude and phase noise on the signal due to relative intensity noise (RIN) transfer from the pump are compared for two pumping configurations: first-order backward pumping and bi-directional pumping. Experimental results indicate that with increased Raman backward pump power, though the optical signal-to-noise ratio (OSNR) is increased, so is the pump-induced amplitude and phase noise. The transmission performance is firstly improved by the enhanced OSNR at a low pump power until an optimum point is reached, and then the impairments due to pump-induced noise start to dominate. However, the introduction of a low pump power in the forward direction can further improve the system's performance.

  • 124.
    Pang, Xiaodan
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, Oskars
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Zhang, Lu
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Udalcovs, Aleksejs
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Storck, Joakim
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Maisons, Gregory
    mirSense, Ctr Integrat Nanolnnov, F-91120 Palaiseau, France..
    Carras, Mathieu
    mirSense, Ctr Integrat Nanolnnov, F-91120 Palaiseau, France..
    Xiao, Shilin
    Shanghai Jiao Tong Univ, State Key Lab Adv Opt Commun Syst & Networks, Shanghai, Peoples R China..
    Jacobsen, Gunnar
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Lourdudoss, Sebastian
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    4 Gbps PAM-4 and DMT Free Space Transmission using A 4.65-mu m Quantum Cascaded Laser at Room Temperature2017In: 43RD EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC 2017), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    We experimentally demonstrate 4Gbps PAM-4 and DMT transmissions using a quantum cascaded laser (QCL) emitting at mid-wavelength infrared of 4.65-mu m and a commercial infrared photovoltaic detector. The QCL is directly modulated and operated at room temperature with Peltier Cooling.

  • 125.
    Pang, Xiaodan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Rodrigo Navarro, Jaime
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Olmedo, Miguel Iglesias
    Ozolins, Oskars
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC. KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Udalcovs, Aleksejs
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Advanced Modulations and DSP Enabling High-speed Coherent Communication Using Large Linewidth Lasers2016In: 2016 PROGRESS IN ELECTROMAGNETICS RESEARCH SYMPOSIUM (PIERS), IEEE , 2016, p. 4849-4849Conference paper (Refereed)
  • 126.
    Pang, Xiaodan
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Van Kerrebrouck, J.
    Belgium.
    Ozolins, O.
    Lin, Rui
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Udalcovs, A.
    Zhang, Lu
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Spiga, S.
    Germany.
    Amann, M. C.
    Germany.
    Van Steenberge, G.
    Belgium.
    Gan, L.
    China.
    Tang, M.
    China.
    Fu, S.
    China.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Jacobsen, G.
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Liu, D.
    China.
    Tong, W.
    China.
    Torfs, G.
    Belgium.
    Bauwelinck, J.
    Belgium.
    Yin, X.
    Belgium.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    7×100 Gbps PAM-4 transmission over 1-km and 10-km single mode 7-core fiber using 1.5-μm SM-VCSEL2018In: Optics InfoBase Conference Papers, Optical Society of America, 2018Conference paper (Refereed)
    Abstract [en]

    100 Gbps/λ/core PAM-4 transmission is successfully demonstrated over 1-km and 10- km single mode 7-core fiber links, enabled by directly modulated 1.5-μm single mode VCSEL of 23 GHz modulation bandwidth with pre- and post- digital equalizations.

  • 127.
    Pang, Xiaodan
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Van Kerrebrouck, J.
    Belgium.
    Ozolins, O.
    Sweden.
    Lin, Rui
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Udalcovs, A.
    Sweden.
    Zhang, Lu
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Spiga, S.
    Germany.
    Amann, M. C.
    Germany.
    Van Steenberge, G.
    Belgium.
    Gan, L.
    China.
    Tang, M.
    China.
    Fu, S.
    China.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Jacobsen, G.
    Sweden.
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Liu, D.
    China.
    Tong, W.
    China.
    Torfs, G.
    Belgium.
    Bauwelinck, J.
    Belgium.
    Yin, X.
    Belgium.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    High-speed SDM interconnects with directly-modulated 1.5-μm VCSEL enabled by low-complexity signal processing techniques2018In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2018Conference paper (Refereed)
    Abstract [en]

    We report on our recent work in supporting up to 100 Gbps/λ/core transmissions with a directly modulated 1.5-μm single mode VCSEL and multicore fiber, enabled by low-compleixty pre- and post- digital equalizations.

  • 128.
    Pang, Xiaodan
    et al.
    KTH. RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Van Kerrebrouck, Joris
    Univ Ghent, Imec, INTEC, IDLab, Ghent, Belgium..
    Ozolins, Oskars
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Lin, Rui
    KTH. Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Udalcovs, Aleksejs
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Zhang, Lu
    KTH.
    Spiga, Silvia
    Tech Univ Munich, Walter Schottky Inst, Garching, Germany..
    Amann, Markus C.
    Tech Univ Munich, Walter Schottky Inst, Garching, Germany..
    Van Steenberge, Geert
    Univ Ghent, Imec, CMST, Ghent, Belgium..
    Gan, Lin
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Tang, Ming
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Fu, Songnian
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Schatz, Richard
    KTH.
    Jacobsen, Gunnar
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Popov, Sergei
    KTH.
    Liu, Deming
    Huazhong Univ Sci & Technol, Wuhan, Hubei, Peoples R China..
    Tong, Weijun
    Yangtze Opt Fiber & Cable Joint Stock Ltd Co, Wuhan, Hubei, Peoples R China..
    Torfs, Guy
    Univ Ghent, Imec, INTEC, IDLab, Ghent, Belgium..
    Bauwelinck, Johan
    Univ Ghent, Imec, INTEC, IDLab, Ghent, Belgium..
    Yin, Xin
    Univ Ghent, Imec, INTEC, IDLab, Ghent, Belgium..
    Chen, Jiajia
    KTH.
    7x100 Gbps PAM-4 Transmission over 1-km and 10-km Single Mode 7-core Fiber using 1.5-mu m SM-VCSEL2018In: 2018 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXPOSITION (OFC), Institute of Electrical and Electronics Engineers (IEEE), 2018Conference paper (Refereed)
    Abstract [en]

    100 Gbps/lambda/core PAM-4 transmission is successfully demonstrated over 1-km and 10km single mode 7-core fiber links, enabled by directly modulated 1.5-mu m single mode VCSEL of 23 GHz modulation bandwidth with pre-and post-digital equalizations.

  • 129. Pfrommer, H.
    et al.
    Piqueras, M. A.
    Herrera, J.
    Polo, V.
    Martinez, A.
    Karlsson, S.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Yu, Y.
    Tsegaye, I.
    Liu, C. P.
    Chuang, C. H.
    Enard, A.
    Van Dijk, F.
    Seeds, A. J.
    Marti, J.
    Full-duplex DOCSIS/wirelessDOCSIS fiber-radio network employing packaged AFPM-based base-stations2006In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 18, no 04-jan, p. 406-408Article in journal (Refereed)
    Abstract [en]

    The simultaneous wireline (600 MHz) and wireless (5.5 GHz) transmission of data over cable service interface specification (DOCSIS) signals in a hybrid fiber-radio access network is presented. The DOCSIS signal wireless replica is generated by means of an optical harmonic up-conversion technique based on a dual-drive Mach-Zehnder modulator. The optical signal is fed to a base station (BS) where a packaged asymmetric Fabry-Perot modulator/detector acts simultaneously as a photodetector and an optical modulator. At the BS, the DOCSIS signals can be fed either to a wireline or a wireless access network, in a highly flexible approach. Full-duplex operation has been demonstrated for both access types, including indoor wireless transmission.

  • 130. Pfrommer, H.
    et al.
    Piqueras, M. A.
    Herrera, J.
    Polo, V.
    Martinez, A.
    Karlsson, Stefan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Enard, A.
    Van Dijk, F.
    Yu, Yichuan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tsegaye, Tedros
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Liu, C. P.
    Chuang, C. H.
    Marti, J.
    Seeds, A. J.
    Experimental Demonstration of Full-Duplex DOCSIS Signal Transmissions over a Wireline/Wireless-Fibre Access Network2006In: 2006 International Topical Meeting on Microwaves Photonics, 2006, p. 89-92Conference paper (Refereed)
    Abstract [en]

    A fibre-radio access network architecture for simultaneous wireline and wireless transmissions of data over cable service interface specification (DOCSIS) signals is presented. An all-optical harmonic up-conversion technique using a dual-drive Mach-Zehnder modulator (DD-MZM) is employed at the central station while an InGaAsP/InGaAsP multiple quantum well (MQW) asymmetric Fabry-Perot modulator/detector (AFPM) functions as a single optical/electrical transducer performing optical intensity modulation and photodetection simultaneously at the base station. Full-duplex operation is demonstrated for both access types in an indoor laboratory environment as well as in a small-scale outdoor field trial

  • 131. Piels, M.
    et al.
    Olmedo, Miguel Iglesias
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Technical University of Denmark, Denmark.
    Pang, Xiaodan
    RISE ACREO AB.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Acreo AB, Sweden.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zibar, D.
    Rate equation-based phase recovery for semiconductor laser coherent transmitters2015In: Optical Fiber Communication Conference, OFC 2015, OSA - The Optical Society , 2015Conference paper (Refereed)
    Abstract [en]

    We present a novel carrier recovery technique for coherent systems with semiconductor lasers that incorporates the laser dynamics. A sensitivity improvement of 8dB over a decisiondirected phase-locked loop is achieved experimentally for 28GBd DP-16QAM.

  • 132. Piels, Molly
    et al.
    Olmedo, Miguel Iglesias
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Xue, Weiqi
    Pang, Xiaodan
    Schaffer, Christian
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Networking and Transmission Laboratory, Acreo AB, Kista, Sweden.
    Monroy, Idelfonso Tafur
    Mork, Jesper
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zibar, Darko
    Laser Rate Equation-Based Filtering for Carrier Recovery in Characterization and Communication2015In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 33, no 15, p. 3271-3279Article in journal (Refereed)
    Abstract [en]

    We formulate a semiconductor laser rate equation-based approach to carrier recovery in a Bayesian filtering framework. Filter stability and the effect of model inaccuracies (unknown or unuseable rate equation coefficients) are discussed. Two potential application areas are explored: Laser characterization and carrier recovery in coherent communication. Two rate equation-based Bayesian filters, the particle filter and extended Kalman filter, are used in conjunction with a coherent receiver to measure frequency noise spectrum of a photonic crystal cavity laser with less than 20 nW of fiber-coupled output power. The extended Kalman filter is also used to recover a 28-GBd DP-16 QAM signal where a decision-directed phase-locked loop fails.

  • 133.
    Popov, Sergei
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Navarro, J. R.
    Pang, Xiaodan
    Ozolins, O.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Louchet, H.
    Jacobsen, G.
    Equalization-Enhanced Phase Noise in Coherent Optical Communications Systems2016In: 2016 18TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON), IEEE, 2016Conference paper (Refereed)
    Abstract
  • 134. Pusa, F.
    et al.
    Skagerlund, J.
    Gillner, L.
    Sahlen, O.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Granestrand, P.
    Lundqvist, L.
    Stoltz, B.
    Terlecki, J.
    Wahlin, F.
    Morner, A. -C
    Wallin, J.
    Oberg, O.
    An automatic method to extract the grating coupling coefficient in DFB lasers: evaluation of different types of fabricated lasers1997In: Integrated Optics and Optical Fibre Communications, 11th International Conference on, and 23rd European Conference on Optical Communications (Conf. Publ. No. 448), 1997, Vol. 2, p. 200-203Conference paper (Refereed)
    Abstract [en]

    The grating coupling coefficients for a large number of 1.3 mu;m and 1.55 mu;m MQW DFB lasers with no, one, or two facets as-cleaved have been successfully extracted from spontaneous emission spectra

  • 135. Rigole, P. J.
    et al.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Goobar, E.
    Saavedra, A. A.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Modulation and noise measurements from 1520 to 1560 nm in monolithic widely tunable semiconductor lasers1998In: Lasers and Electro-Optics, 1998. CLEO 98. Technical Digest. Summaries of papers presented at the Conference on, 1998, p. 303-304Conference paper (Refereed)
    Abstract [en]

    Widely tunable semiconductor lasers have a large number of applications. We believe we report for the first time measurements of intensity modulation response, frequency, and intensity noise characteristics of a grating-assisted co-directional coupler with rear sampled grating reflector (GCSR) lasers

  • 136.
    Rodrigo Navarro, Jaime
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Kakkar, Aditya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Pang, Xiaodan
    Ozolins, Oskars
    Udalcovs, Aleksejs
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    Design of Multi-Stage Carrier Phase Recovery Schemes for  high  order  Coherent  Optical  mQAM  SystemsArticle in journal (Refereed)
  • 137.
    Rodrigo Navarro, Jaime
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO. Acreo Swedish ICI'AB, Sweden.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Acreo Swedish ICI'AB, Sweden.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Pang, X.
    Ozolins, O.
    Nordwall, F.
    Louchet, H.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Jacobsen, G.
    High performance and low complexity carrier phase recovery schemes for 64-QAM coherent optical systems2017In: 2017 Optical Fiber Communications Conference and Exhibition, OFC 2017 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2017Conference paper (Refereed)
    Abstract [en]

    We experimentally validate two novel CPR schemes outperforming existing CPRs in complexity and performance. A complexity reduction of at least a factor of 4 is reported compared to the BPS algorithm for a 64QAM system.

  • 138.
    Rodrigo Navarro, Jaime
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Kakkar, Aditya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Pang, Xiaodan
    Acreo Swedish, Sweden.
    Ozolins, Oskars
    Acreo Swedish, Sweden.
    Fredrik, Nordwall
    Louchet, Hadrien
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnnar
    High Performance and Low Complexity Carrier Phase Recovery Schemes for 64-QAM Coherent Optical Systems2017In: Optics InfoBase Conference Papers, Optical Society of America, 2017Conference paper (Refereed)
    Abstract [en]

    We experimentally validate two novel CPR schemes outperforming existing CPRs in complexity and performance. A complexity reduction of at least a factor of 4 is reported compared to the BPS algorithm for a 64QAM system.

  • 139.
    Rodrigo Navarro, Jaime
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Kakkar, Aditya
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI).
    Pang, Xiaodan
    RISE ACREO AB.
    Ozolins, Oskars
    Udalcovs, Aleksejs
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnnar
    Blind  phase  search  with  angular  quantization  noise mitigation for efficient carrier phase recovery2017In: Photonics, ISSN 2304-6732, Vol. 4, no 2, article id 37Article in journal (Refereed)
    Abstract [en]

    The inherent discrete phase search nature of the conventional blind phase search (C-BPS) algorithm is found to introduce angular quantization noise in its phase noise estimator. The angular quantization noise found in the C-BPS is shown to limit its achievable performance and its potential low complexity implementation. A novel filtered BPS algorithm (F-BPS) is proposed and demonstrated to mitigate this quantization noise by performing a low pass filter operation on the C-BPS phase noise estimator. The improved performance of the proposed F-BPS algorithm makes it possible to significantly reduce the number of necessary test phases to achieve the C-BPS performance, thereby allowing for a drastic reduction of its practical implementation complexity. The proposed F-BPS scheme performance is evaluated on a 28-Gbaud 16QAM and 64QAM both in simulations and experimentally. Results confirm a substantial improvement of the performance along with a significant reduction of its potential implementation complexity compared to that of the C-BPS.

  • 140.
    Rodrigo Navarro, Jaime
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO. Acreo Swedish, Sweden.
    Pang, Xiaodan
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Ozolins, Oskars
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Adaptive Boundaries Scheme for Cycle-Slip Mitigation in C-mQAM Coherent Systems2015In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 27, no 20, p. 2154-2157Article in journal (Refereed)
    Abstract [en]

    We propose a method for cycle-slip mitigation in circular multilevel quadrature amplitude modulation (C-mQAM) coherent optical systems, with constellation rotational asymmetry, based on an adaptive boundaries approach. The impact of cycle-slips in C-mQAM coming from Viterbi-Viterbi algorithm limits the phase noise tolerance. By introducing adaptive boundaries and a differential coding scheme, the ambiguity of asymmetrical rotation of constellation can be effectively removed. Performance of the proposed method is evaluated for a C-16QAM and C-64QAM for various laser linewidths. Results show a noticeable improvement in linewidth symbol duration product (Delta(upsilon) . T-S) tolerance compared with the previous studies on C-mQAM and mQAM constellations. The Delta(upsilon) . T-S tolerance reaches 4 x 10(-4) and 1.1 x 10(-4) for C-16QAM and C-64QAM, respectively, for 1 dB penalty at a symbol error rate of 10(-3).

  • 141. Rosa, P.
    et al.
    Rizzelli, G.
    Pang, Xiaodan
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, O.
    Udalcovs, A.
    Tan, M.
    Sergeyev, S.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Jacobsen, G.
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Ania-Castañón, J. D.
    Unrepeatered 64QAM over SMF-28 using Raman amplification and digital backpropagation2017In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2017Conference paper (Refereed)
    Abstract [en]

    Unrepeatered transmission over SMF-28 fibre is investigated using Raman based amplification. Experiments and simulations demonstrate a transmission up to 200 km (41 dB) span length using 28Gbaud 64 QAM modulation employing digital back propagation in DSP.

  • 142.
    Saavedra, A. A.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Rigole, P. -J
    Goobar, E.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Nilsson, S.
    Amplitude and frequency modulation characteristics of widely tunable GCSR lasers1998In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 10, p. 1383-1385Article in journal (Refereed)
    Abstract [en]

    The amplitude (AM) and frequency (FM) modulation responses of a grating assisted codirectional coupler with rear sampled grating reflector laser were measured over a 40-nm tuning range. The extracted modulation bandwidth varied between 3 and 4 GHz and parameters as parasitic cutoff, maximum relaxation frequency and K-factor were extracted from curve fittings to the AM response. The frequency modulation measurements revealed low chirp despite the large tunability of the device. The linewidth enhancement factor was calculated from the AM and FM measurements. The values ranges from three to nine for ten different operating wavelengths

  • 143.
    Saavedra, A. A.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Rigole, P. -J
    Goobar, E.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Nilsson, S.
    Measurement of amplitude and frequency modulation responses of widely tunable GCSR lasers1998In: Semiconductor Laser Conference, 1998. ISLC 1998 NARA. 1998 IEEE 16th International, 1998, p. 179-180Conference paper (Refereed)
    Abstract [en]

    The amplitude and frequency modulation responses of a grating assisted codirectional coupler (GCSR) semiconductor laser were measured over 40 nm tuning range. The extracted modulation bandwidth varied between 3 and 4 GHz and the linewidth enhancement factors range from 3 to 9

  • 144.
    Saavedra, A. A.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Rigole, P. -J
    Goobar, E.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Nilsson, S.
    Relative intensity noise and linewidth measurements of a widely tunable GCSR laser1998In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 10, p. 481-483Article in journal (Refereed)
    Abstract [en]

    The intensity and frequency noise of a grating assisted codirectional coupler with rear sampled grating reflector laser with 40-nm tuning range and 35-dB sidemode suppression ratio (SMSR) have been measured. The linewidth varies from 430 kHz to 4 MHz as a function of tuning. The resonance frequency, intrinsic bandwidth and damping factor for this device were extracted from the relative intensity noise (RIN) measurements. At high bias, the RIN is -150 dB/Hz and the maximum resonance frequency is 4.5 GHz

  • 145.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Dynamics of spatial hole burning effects in DFB lasers1995In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 31, p. 1981-1993Article in journal (Refereed)
    Abstract [en]

    A lumped small-signal model for intensity and frequency modulation response of semiconductor lasers, including the effects of longitudinal spatial hole burning (SHB), is presented. It is shown that the laser dynamics including SHB-effects can be accurately described by three small-signal rate equations. The simplicity of the model gives new insight into SHB-effects on modulation response and cavity state stability. It is shown that SHB-effects have a cut-off frequency that depends on the carrier lifetime (including stimulated recombination) and the feedback of perturbations in the longitudinal intensity distribution during modulation

  • 146.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Longitudinal spatial instability in symmetric semiconductor lasers due to spatial hole burning1992In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 28, p. 1443-1449Article in journal (Refereed)
    Abstract [en]

    A novel type of longitudinal instability due to spatial hole burning in symmetric semiconductor laser structures (DFB lasers in particular) is examined analytically and numerically. It is shown that, at a certain output power, the gain and refractive index spatial distributions of the lasing mode become unstable. Above this output power, the modal gains and oscillation frequencies change drastically, which often causes multimode operation. A measure of the cavity stability is introduced and derived analytically for a Fabry-Perot and a single phase-shifted DFB laser. Results from numerical simulations of a multiple phase-shifted DFB laser are presented

  • 147.
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    On the Stability and Dynamics of Semiconductor Lasers1994Doctoral thesis, comprehensive summary (Other academic)
  • 148.
    Schatz, Richard
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ackerman, David
    An efficient method for accurate calculation of second order distortion in DFB lasers1994Report (Other academic)
    Abstract [en]

    A dynamic model for second order distortion in semiconductor lasers is presented. The model includes spatial hole burning effects and can be used for fast and accurate calculation of single tone, two tone and composite second order distortion. It is shown that lasers oscillating on the short wavelength side of the Bragg wavelength have considerable higher distortion than lasers oscillating on the long wavelength side.

  • 149.
    Schatz, Richard
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Berglind, Eilert
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Gillner, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Parameter extraction from DFB lasers by means of a simple expression for the spontaneous emission spectrum1994In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 6, p. 1182-1184Article in journal (Refereed)
    Abstract [en]

    A simple expression for the amplified spontaneous emission from a laser biased below lasing threshold is applied to semiconductor laser parameter extraction. We demonstrate that accurate measurement of the coupling coefficient for distributed feedback (DFB) lasers with phaseshifts and end reflections is a practical possibility. It is also shown that the used expression, for a reciprocal device, can be derived directly from the wave equation using the Green’s function.<>

  • 150.
    Schatz, Richard
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Bethea, C. G.
    Steady state model for facet heating leading to thermal runaway in semiconductor lasers1994In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 76, p. 2509-2521Article in journal (Refereed)
    Abstract [en]

    A steady state model is presented which provides new insight into the thermal runaway process that leads to catastrophic damage of semiconductor lasers. We show that thermal runaway is preceded by a situation where two self consistent thermal steady state solutions exist at low output power, one stable and one unstable. When the output power is increased, the two solutions degenerate and disappear which means that the laser will enter thermal runaway. The steady state model consists of two parts: a three dimensional thermal model and a one dimensional model for the carrier diffusion towards the facet. The temperature dependence of both the heat sources and the thermal conductivity play the crucial role. Also ordinary bulk heating is shown to be an important factor. Both 0.88 #x3bc;m GaAs lasers and 1.5 #x3bc;m InGaAsP lasers are discussed and minimum values of surface recombination and output power needed for thermal runaway are given. Thermal runaway in GaAs lasers can be explained by the model for realistic values of surface recombination. However, the calculated values of needed output power are significantly higher than what is experienced in reality. Possible explanations for this discrepancy are given.

1234 101 - 150 of 191
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf