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  • 1. Aggerstam, Thomas
    et al.
    Lovqvist, Anita
    Stevens, Renaud
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Jonsson, Stefan
    Marcks von Würtemberg, Richard
    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 Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Dubois, Mardjan
    Ghisoni, Marco
    Selectively oxidized vertical-cavity surface-emitting lasers for high-speed data communication2001In: Proc. SPIE 4286, SPIE's Optoelectronics 2001, Photonics West, San Jose, US, Bellingham, WA, ETATS-UNIS: Society of Photo-Optical Instrumentation Engineers , 2001, Vol. 4286, p. 96-Conference paper (Refereed)
    Abstract [en]

    MITEL Semiconductor is developing the next generation low cost, high performance transceivers for data communication. The increasing quantity of data being transferred over the Internet demands very high capacity interconnects. A low cost, high-performance alternative is the use of parallel fiber interconnects where the light is, for example, coupled into a 12-channel fiber-ribbon. Parallel interconnects require good uniformity in order to reduce escalating costs and complexity. In this paper we report on the static and the modulation properties of 850nm multimode oxide VCSELs for use in such Gb/s transceiver system. Static power-current-voltage characteristics with good uniformity were obtained for different structures, with threshold currents down to sub-mA. A maximum small signal 3-dB bandwidth of 10 GHz and a modulation current efficiency up to 8.4 GHz/√[mA] were measured. Single channel results are presented for VCSELs operated at data rates from 2.5-10Gb/s.

  • 2. Ahlfeldt, H.
    et al.
    Holm, J.
    Lindgren, S.
    Backlin, L.
    Vieider, C.
    Klinga, T.
    Kerzar, B.
    Nilsson, M.
    Svensson, M.
    Nilsson, S.
    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 Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    20 GHz bandwidth of lasers flip-chip-mounted on microstructured carriers with integrated electrical waveguides1998In: Optical Communication, 1998. 24th European Conference on, 1998, Vol. 1, p. 205-206Conference paper (Refereed)
    Abstract [en]

    A flip-chip-mounting scheme for high-speed lasers has been realised. The mounting scheme involves a microstructured silicon carrier with integrated membrane transmission lines and self-aligning solder bumps

  • 3. Akram, M. N.
    et al.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Marcinkevicius, Saulius
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Berggren, J.
    Experimental evaluation of carrier transport, gain, T0 and chirp of 1.55 mm MQW structures with different barrier compositions2005In: 31st European Conference on Optical Communications (ECOC 2005), 2005, Institution of Engineering and Technology, 2005, Vol. 2005, no CP502, p. 297-298Conference paper (Refereed)
    Abstract [en]

    Direct carrier transport measurements were performed for different InGaAsP/InGaAlAs MQW test structures. Shallow InGaAlAs barrier QW showed faster carrier transport. Semi-insulating regrown FP lasers with InGaAlAs barrier QW showed improved high temperature operation, modal gain, differential modal gain and chirp.

  • 4. Akram, N. M.
    et al.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Marcinkevicius, Saulius
    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.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Experimental evaluation of carrier transport, gain, T0 and chirp of 1.55 mu;m MQW structures with different barrier compositions2005In: Optical Communication, 2005. ECOC 2005. 31st European Conference on, 2005, Vol. 2, p. 297-298Conference paper (Refereed)
    Abstract [en]

    Direct carrier transport measurements were performed for different InGaAsP/InGaAlAs MQW test structures. Shallow InGaAlAs barrier QW showed faster carrier transport. Semi-insulating regrown FP lasers with InGaAlAs barrier QW showed improved high temperature operation, modal gain, differential modal gain and chirp.

  • 5.
    Akram, Nadeem
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chacinski, Marek
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Berrier, Audrey
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Experimental characterization of high-speed 1.55 mu m buried heterostructure InGaAsP/InGaAlAs quantum-well lasers2009In: Journal of the Optical Society of America. B, Optical physics, ISSN 0740-3224, E-ISSN 1520-8540, Vol. 26, no 2, p. 318-327Article in journal (Refereed)
    Abstract [en]

    Detailed experimental characterization is performed for 1550 nm semi-insulating regrown buried heterostructure Fabry-Perot (FP) lasers having 20 InGaAsP/InGaAlAs strain-balanced quantum wells (QWs) in the active region. Light-current-voltage performance, electrical impedance, small-signal response below and above threshold, amplified spontaneous emission spectrum below threshold and relative intensity noise spectrum are measured. Different laser parameters such as external differential quantum efficiency eta(d), background optical loss alpha(i), K-factor, D-factor, characteristic temperature T-0, differential gain dg/dn, gain-compression factor epsilon, carrier density versus current, differential carrier lifetime tau(d), optical gain spectrum below threshold, and chirp parameter alpha are extracted from these measurements. The FP lasers exhibited a high T-0 (78-86.5 degrees C) and very high-resonance frequency (23.7 GHz). The results indicate that appropriately designed lasers having a large number of InGaAsP well/InGaAlAs barrier QWs with shallow valence-band discontinuity can be useful for un-cooled high-speed direct-modulated laser applications.

  • 6.
    Akram, Nadeem
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chacinski, Marek
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Berrier, Audrey
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    High-Speed Performance of 1.55 µm Buried Hetero-Structure Lasers with 20 InGaAsP/InGaAlAs Quantum-Wells2006In: 2006 European Conference on Optical Communications Proceedings, ECOC 2006, IEEE , 2006, p. 1-2Conference paper (Refereed)
    Abstract [en]

    1550 nm re-grown FP lasers having 20 InGaAsP/InGaAlAs strain-balanced QWs exhibit low threshold current density, high T0 (78.0 #x000B0;C) and high resonance frequency (24 GHz) indicating that a large number of shallow barrier QWs are attractive for un-cooled high-speed direct-modulation applications.

  • 7.
    Akram, Nadeem
    et al.
    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.
    Marcinkevičius, Saulius
    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.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Olsson, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    The effect of barrier composition on the vertical carrier transport and lasing properties of 1.55-mu m multiple quantum-well structures2006In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 42, no 7, p. 713-714Article in journal (Refereed)
    Abstract [en]

    In this paper, the effect of barrier bandgap and composition on the optical performance of 1.55-mu m InGaAsP/In-GaAsP and InGaAsP/InGaAlAs multiple quantum-well structures and Fabry-Perot lasers is evaluated experimentally. Direct vertical carrier transport measurements were performed through strain-compensated multiple quantum-well (MQW) test structures using femto-second laser pulse excitation and time-resolved photoluminescence up-conversion method. MQW test structures were grown with different barrier composition (InGaAsP and InGaAlAs) and barrier bandgap (varied from lambda(g) = 1440 to 1260 nm) having different conduction band Delta E-c and valence band discontinuity Delta E-v, while keeping the same InGaAsP well composition for all the structures. The ambipolar carrier transport was found to be faster in the structures with lower valence band discontinuity Delta E-v. Regrown semi-insulating buried heterostructure Fabry-Perot (SIBH-FP) lasers were fabricated from similar QWs and their static light-current-voltage characteristics (including optical gain and chirp spectra below threshold) and thermal characteristics were measured. Lasers with InGaAlAs barrier showed improved high-temperature operation, higher optical gain, higher differential gain, and lower chirp, making them suitable candidates for high-bandwidth directly modulated uncooled laser applications.

  • 8.
    Akram, Nadeem
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Influence of electrical parasitics and drive impedance on the laser modulation response2004In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 16, no 1, p. 21-23Article in journal (Refereed)
    Abstract [en]

    In this letter, we analyze the effects of electrical parasitics and drive impedance on the laser modulation response. It is found that for lasers with small active-region volume, e.g., vertical-cavity surface-emitting lasers, the finite drive impedance and/or the laser parasitic capacitance can significantly enhance the damping of the laser resonance peak at low bias. This is due to the voltage fluctuations across the laser diode active layer during modulation. It is also shown that the real pole of the small-signal response transfer function corresponding to the laser parasitic cutoff frequency is not fixed but decreases with the increased bias level.

  • 9.
    Akram, Nadeem
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Silfvenius, Christofer
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    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.
    Design optimization of InGaAsP-InGaAlAs 1.55 mu;m strain-compensated MQW lasers for direct modulation applications2004In: Indium Phosphide and Related Materials, 2004. 16th IPRM. 2004 International Conference on, IEEE , 2004, p. 418-421Conference paper (Refereed)
    Abstract [en]

    A comprehensive simulation study of InGaAsP (well)/InGaAlAs(barrier) 1.55 mu;m strain-compensated MQW lasers is presented. For MQWs, a uniform vertical distribution of holes is achieved due to a reduced effective hole confinement energy by optimizing the bandgap and strain of the barriers and p-doping in the active region. Some preliminary results are also presented for the manufactured lasers using these QWs indicating a good material platform.

  • 10.
    Akram, Nadeem
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Silfvenius, Christofer
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Design optimization of InGaAsP-InGaAlAs 1.55 mu m strain-compensated MQW lasers for direct modulation applications2004In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 19, no 5, p. 615-625Article in journal (Refereed)
    Abstract [en]

    In this paper, a simulation study of InGaAsP(well)/InGaAlAs(barrier) 1.55 mum strain-compensated multi-quantum well (MQW) lasers is presented. Due to a large conduction band discontinuity in this material system, a higher material gain and differential gain can be obtained from such a quantum well (QW) as compared to a traditional InGaAsP/InGaAsP quantum well. The deeper electron well should also improve elevated temperature operating characteristics and reduce the electron spillover from QWs. For MQWs, a uniform vertical distribution of holes is achieved due to a reduced effective hole confinement energy by optimizing the bandgap and the strain in the barriers. A large number of quantum wells can be uniformly pumped, reducing the carrier density in each individual well. A uniform and low carrier density in all the wells help reduce the total Auger recombination current. High p-doping in the active region is shown to enhance the carrier and gain non-uniformity in the MQWs. A simulated high modulation bandwidth has been demonstrated, promising directly modulated lasers as a low-cost source for short to medium distance (1-10 km) high speed optical links.

  • 11. Al-Awis, S. N.
    et al.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Pang, Xiaodan
    RISE ACREO AB.
    Ozolins, O.
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Fattah, A. Y.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Phenomenological formula for modelling of physical layer impairments in elastic optical networks2015In: Asia Communications and Photonics Conference, ACPC 2015, 2015Conference paper (Refereed)
    Abstract [en]

    An empirical modelling technique is introduced to estimate impact of physical layer impairments in elastic optical networks, which can be used to evaluate transmission quality. The model has been verified experimentally with accuracy beyond (97.3%). © 2015 OSA.

  • 12.
    Angulo Barrios, C.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Lourdudoss, Sebastian
    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.
    Messmer, L. R.
    Holmgren, M.
    Lovqvist, A.
    Carlsson, C.
    Larsson, A.
    Halonen, J.
    Ghisoni, M.
    Stevens, Renaud
    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 Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    GaAs/AlGaAs buried-heterostructure laser diodes with semi-insulating GaInP:Fe regrowth2001In: Lasers and Electro-Optics, 2001. CLEO/Pacific Rim 2001. The 4th Pacific Rim Conference on, 2001, Vol. 2Conference paper (Refereed)
    Abstract [en]

    GaAs/AlGaAs buried-heterostructure in-plane lasers and vertical-cavity surface-emitting lasers using GaInP:Fe as the burying layer have been fabricated and investigated. Regrowth of GaInP:Fe around etched laser mesas was achieved by hydride vapor phase epitaxy. The lasers exhibit good performance under CW operation and show promising high-speed characteristics.

  • 13. Bandelow, U.
    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.
    Wunsche, H. -J
    A correct single-mode photon rate equation for multisection lasers1996In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 8, p. 614-616Article in journal (Refereed)
    Abstract [en]

    It is shown that not the photon number but photon number divided by the square root of the excess factor of spontaneous emission must be used in the photon rate equation for single-mode lasers when the longitudinal field distribution changes with time. The importance of using the correct dynamic quantity is illustrated with two examples.

  • 14. Carlsson, C.
    et al.
    Martinsson, H.
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Halonen, J.
    Larsson, A.
    Analog modulation properties of oxide confined VCSELs at microwave frequencies2002In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 20, no 9, p. 1740-1749Article in journal (Refereed)
    Abstract [en]

    Motivated by the need for affordable, high-performance fiber-optic microwave links in fiber-fed microcellular networks and radar systems, we have performed a comprehensive experimental evaluation of the microwave modulation characteristics of high-speed oxide-confined vertical cavity surface emitting lasers (VCSELs) emitting at 840 inn. VCSELs with different oxide aperture diameters, including both single- and multimode lasers, have been used to track the dependence on modal behavior. The study includes both static and dynamic characteristics, with an emphasis on those of major importance for analog modulation. This includes the small-signal modulation response (S-11 and S-21), the relative intensity noise (RIN), and the intermodulation distortion. From this, we determine the spurious free dynamic range, the impedance characteristics, and the speed limitations.

  • 15. Carlsson, C.
    et al.
    Modh, P.
    Halonen, J.
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Larsson, A.
    High-frequency analog modulation of oxide confined 670-nm vertical-cavity surface-emitting lasers2004In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 43, no 12, p. 3138-3141Article in journal (Refereed)
    Abstract [en]

    We investigate the bandwidth limitations and the analog modulation characteristics at microwave frequencies (0.1 to 10 GHz)of a low-capacitance oxide-confined 670-nm InGaAIP vertical-cavity surface-emitting laser (VCSEL). A maximum modulation bandwidth of 6.3 GHz, limited by thermal effects, is achieved. From measurements of distortion and noise, a spurious free dynamic range (SFDR) of 100 dB Hz(2/3) is obtained at frequencies up to 2 GHz, rendering such VCSELs useful for transmission of analog signals. At higher frequencies, the SFDR drops due to the thermally limited resonance frequency.

  • 16. Chacinski, M.
    et al.
    Chitica, N.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Transmission of 40 Gb/s over 55 m multimode fiber using 12 GHz bandwidth system based on vertical-cavity surface-emitting laser2014In: Asia Communications and Photonics Conference, ACP, 2014Conference paper (Refereed)
    Abstract [en]

    Error free transmission (E-12) over 55 m long standard MMF at 40 Gb/s data rate is demonstrated with moderate signal conditioning on the VCSEL. The VCSEL has a-3 dBe bandwidth of 15 GHz resulting in system bandwidth of 12GHz, giving 3.3 bit/s/Hz coding efficiency.

  • 17.
    Chacinski, Marek
    et al.
    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. KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Berggren, Jesper
    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 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 (Closed 20120101), Photonics (Closed 20120101).
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hammar, Mattias
    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.
    Sundgren, Petrus
    Marcks von Würtemberg, Rikard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    1.3 um InGaAs VCSELs: Influence of the Large Gain-Cavity Detuning on the Modulation and Static Performance2004In: Proc. of 30th European Conference on Optical Communication 2004, 2004Conference paper (Refereed)
  • 18.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC. KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Djupsjoebacka, Anders
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Fonjallaz, Pierre-Yves
    Tipsuwannakul, Ekawit
    KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Udvary, Eszter
    400km Transmission of STM-16 Data on Baseband and DVBT on 40GHz Subcarrier2008In: 2008 INTERNATIONAL CONFERENCE ON TELECOMMUNICATIONS, VOLS 1 AND 2, NEW YORK: IEEE , 2008, p. 350-352Conference paper (Refereed)
    Abstract [en]

    A 400 km standard single mode fiber (SSMF) link with a single light-intensity modulator was upgraded for simultaneous transmission of STM-16 2.5Gbps baseband data and Digital-Video-Broadcast-Terrestrial DVBT utilizing a 40GHz subcarrier. An optical circulator and narrowband fiber Bragg gratings (FBG) were used to separate the signals in the optical domain and allow for simple direct baseband detection of both.

  • 19.
    Chacinski, Marek G.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Isaksson, Mats
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Wang, Qin
    Effects of detuned loading on the modulation performance of widely tunable MG-Y lasers2008In: Semiconductor Lasers And Laser Dynamics III / [ed] Panajotov, KP; Sciamanna, M; Valle, AA; Michalzik, R, 2008, Vol. 6997, p. 99709-99709Conference paper (Refereed)
    Abstract [en]

    The Detuning Loading Effect, i.e., the effects of the modulation performance on the position of the lasing mode relative to the Bragg reflection peak, is investigated in a Modulated Grating Y-branch laser. By proper adjustment of the lasing mode position, simultaneous chirp reduction and modulation bandwidth enhancement can be obtained. The lasing mode position is also crucial for side mode suppression ratio and output power.

  • 20.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Isaksson, Mats
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Schatz, Johan Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    High-speed direct Modulation of widely tunable MG-Y laser2005In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 17, no 6, p. 1157-1159Article in journal (Refereed)
    Abstract [en]

    The dynamic performance of the modulated-grating Y-branch laser is presented. In order to reach over 40-nm tuning range, the devices utilize an additive Vernier effect and relative tuning of two reflecting gratings. The device shows high (> 13 dBrn ex-facet) and uniform (< 1.2-dB variation) steady state output power over the tuning range, and sidemode suppression ratio > d40 dB. The laser behavior under small- and large-signal operation conditions is investigated. The laser exhibits a resonance frequency of 7.4-8.8 GHz at 80-mA bias. A 10-Gb/s eye diagram measurement showed, high extinction ratio and signal-to-noise ratio.

  • 21.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Isaksson, Mats
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    D'Oosterlinck, W.
    Morthier, G.
    Widely Tunable Wavelength Conversion 10 Gb/s Using a Modulated Grating Y-branch Laser Integrated with an Optical Amplifier2007In: OFC/NFOEC 2007 - Optical Fiber Communication and the National Fiber Optic Engineers Conference 2007, 2007Conference paper (Refereed)
    Abstract [en]

    A simple integrated tunable wavelength converter is presented. 10 Gb/s XGM conversion of signals at wavelength 1530-1560 nm to 1531-1556 nm and transmission at 2.5 Gb/s over 25 km SSMF of the converted signals were achieved.

  • 22.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Impact of losses in the Bragg section on the dynamics of detuned loaded DBR lasers2010In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 46, no 9, p. 1360-1367Article in journal (Refereed)
    Abstract [en]

    The dynamics of a distributed Bragg reflector laser with optical losses in the Bragg section is studied in detail. It is found that the modulation response depends not only on the detuning of the lasing wavelength from the Bragg reflectivity peak but also on the magnitude of the waveguide losses in the Bragg section. Depending on the losses, the damping of the relaxation peak can either increase or decrease when the laser is detuned on the long wavelength flank of the Bragg peak. Hence, in order to achieve maximum modulation bandwidth of the laser, the laser needs not only to have the correct detuning but also an optimized waveguide loss in the Bragg section. The physical reason for this dependence is discussed in terms of a modified rate equation model.

  • 23.
    Chacinski, Marek
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Detuned-loading effects on directly-modulated high-speed lasers2004In: 2004 International Students and Young Scientists Workshop Photonics and Microsystems, Proceedings / [ed] Dylewicz, R; Patela, S, NEW YORK: IEEE , 2004, p. 7-7Conference paper (Refereed)
    Abstract [en]

    The modulation bandwidth and linewidth enhancement factor were investigated and found to be strongly dependent on the position of the lasing mode on the Bragg reflection peak.

  • 24.
    Chacinski, Marek
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Schatz, Richard
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Kjebon, Olle
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Directly modulated lasers detuned loading effect2004In: 2004 International Students and Young Scientists Workshop - Photonics and Microsystems, 2004, p. 1-21Conference paper (Refereed)
  • 25.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hammar, Mattias
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Marcks von Würtemberg, Rickard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Mogg, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Sundgren, Petrus
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Berggren, Jesper
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Single-mode 1.27 μm InGaAs vertical cavity surface-emitting lasers with temperature-tolerant modulation characteristics2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 86, no 21, p. 211109-1-211109-3Article in journal (Refereed)
    Abstract [en]

    The dynamic performance of InGaAs/GaAs 1.27 &mu; m single-mode vertical cavity surface emitting lasers (VCSELs) is presented. In order to reach such a long wavelength, the devices utilize highly strained double-quantum wells and a large detuning between the material gain peak and cavity resonance. It is found that the large detuning improves the temperature stability of both static and modulation characteristics. A resonance frequency of 7.8-9.5 GHz and optical power of 0.30 mW in fiber was maintained throughout the investigated temperature range of 20-90 &DEG; C. The intrinsic response of the device suggests that long-wavelength InGaAs/GaAs VCSELs have the potential to be used as low cost uncooled optical transmitters at 10 Gbit/s. &COPY; 2005 American Institute of Physics. &COPY; 2005 American Institute of Physics.

  • 26.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Berggren, Jesper
    Yu, X.
    KTH.
    Marcks Von Würtemberg, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hammar, Mattias
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Dynamic properties of electrically p-n confined, epitaxially regrown 1.27 μm InGaAs single-mode vertical-cavity surface-emitting lasers2009In: IET optoelectronics, ISSN 1751-8768, Vol. 3, no 3, p. 163-167Article in journal (Refereed)
    Abstract [en]

    The dynamic performance including chirp measurements of 1.27 mu m single-mode InGaAs/GaAs vertical-cavity surface-emitting lasers (VCSELs) with a large gain-cavity offset is presented. The VCSELs are based on a novel p-n confinement structure with selective area epitaxial regrowth. A resonance frequency of 9.11 GHz, a slope efficiency of 0.25 W/A and an alpha-factor of 5.7 were measured. The modulation bandwidth is limited by electrical parasitics. Eye diagrams at 5 Gb/s with 7 dB extinction ratio and Q-factor around 5 were obtained. The results are compared with the performance of oxide-confined VCSELs with similar active layer and negative gain-cavity detuning.

  • 27.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Djupsjöbacka, Anders
    Extension of 40 Gbps Link with a Directly Detected 2.5 Gbps Subcarrier Channel2009In: ICTON: 2009 11TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, VOLS 1 AND 2, NEW YORK: IEEE , 2009, p. 204-207Conference paper (Refereed)
    Abstract [en]

    Simultaneous transmission was achieved of 40 Gbps at baseband and 2.5 Gbps modulation on a 50 GHz subcarrier utilizing a single 40 Gbps light-intensity modulator. A novel reception method based on optically separated baseband and single sideband channel permits direct detection of both signals with use of bandwidth limited photodiodes and dispersion tolerant transmission. This method can be used to increase the total capacity of an original 40 Gbps optical link to also carry a secondary signal.

  • 28.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Scholes, A.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Ericsson, P.
    Isaksson, Mats
    KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Hammerfeldt, S.
    Silicon optical bench for flip-chip integration of high speed widely tunable lasers2008In: Second International Conference On Advanced Optoelectronics And Lasers / [ed] Sukhoivanov, IA; Svich, VA; Shmaliy, YS, 2008, Vol. 7009, p. 904-904Conference paper (Refereed)
    Abstract [en]

    A silicon optical bench for flip chip mounted widely tunable modulated-grating Y-branch lasers is presented. Its impact on the static and dynamic performance of the laser device is evaluated and compared with a conventional aluminum nitride carrier. The carriers exhibited similar thermal and static performance but the dynamic performance was limited by the electrode layout and the higher microwave losses of the silicon optical bench. With improved microwave design of the electrodes, flip-chip mounting on a silicon optical bench is promising for low cost assembly of high-speed multi-electrode devices

  • 29.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Scholes, A.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Ericsson, P
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Isaksson, Mats
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Hammerfeldt, S.
    A silicon optical bench for flip chip mounting of widely tunable modulated grating Y-branch lasers2005In: CAOL 2005: Proceedings of the 2nd International Conference on Advanced Optoelectronics and Lasers, Vol 1 / [ed] Sukhoivanov, IA, 2005, p. 64-66Conference paper (Refereed)
    Abstract [en]

    A silicon optical bench for flip chip mounted widely tunable lasers is presented. Its impact on the static and dynamic characteristics of the laser device is evaluated and compared with a conventional aluminium nitride carrier.

  • 30.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Thylen, Lars
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Schatz, Richards
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Li, J.
    Djupsjobacka, A.
    Stoltz, B.
    Modulation and chirp evaluation of 100 GHz DFB-TWEAM2010In: European Conference on Optical Communication, ECOC, NEW YORK: IEEE , 2010Conference paper (Refereed)
    Abstract [en]

    The modulation and chirp performance of an InGaAsP based monolithically integrated distributed feedback (DFB) laser and travelling wave electro-absorption modulator (TWEAM) designed for 100Gb/s operation is presented. Open eye-diagrams at 100Gb/s, and error free 50Gb/s BER (limited by measurement system) were achieved. The chirp factor varied between 1.5 and 0 for absorptions between 10% and 90%.

  • 31.
    Chacinski, Marek
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    50 Gb/s modulation and/or detection with a travelling-wave electro-absorption transceiver2008In: 2008 Conference on Optical Fiber Communication/National Fiber Optic Engineers Conference: Vols 1-8, 2008, p. 94-96Conference paper (Refereed)
    Abstract [en]

    Electro-Absorption-Transceiver (EAT) structures used as efficient Travelling-Wave Electro-Absorption-Modulator (TWEAM) as well as Travelling-Wave-Photo-Detector (TWPD) are investigated. Clear eye-openings at 50Gb/s for modulation and for detection are presented. Transmission over 2.2km and 5km SSMF were achieved.

  • 32. Chen, X.
    et al.
    Lin, R.
    Cui, J.
    Gan, L.
    Pang, Xiaodan
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Ozolins, O.
    Udalcovs, A.
    Jiang, T.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    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).
    Tang, M.
    Fu, S.
    Liu, D.
    TDHQ Enabling Fine-Granularity Adaptive Loading for SSB-DMT Systems2018In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 30, no 19, p. 1687-1690, article id 8443443Article in journal (Refereed)
    Abstract [en]

    In this letter, we introduce time domain hybrid quadrature amplitude modulation (TDHQ) for the single sideband discrete multi-tone systems. The experimental results reveal that with a single precoding set and the proposed adaptive loading algorithm, the TDHQ scheme can achieve finer granularity and therefore smoother continuous growth of data rate than that with the conventional quadrature amplitude modulation. Besides, thanks to the frame construction and the tailored mapping rule, the scheme with TDHQ has an obviously better peak to an average power ratio. 

  • 33. El-Taher, Atalla
    et al.
    Pang, Xiaodan
    RISE ACREO AB.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Sergeyev, Sergey
    Noise characterization and transmission evaluation of unrepeated Raman amplified DP-16QAM link2015In: Optical Fiber Communication Conference, 2015Conference paper (Refereed)
    Abstract [en]

    Impairments characterization and performance evaluation of Raman amplified unrepeated DP-16QAM transmissions arc conducted, Experimental results indicate that small gain in forward direction enhance the system signal-to-noise ratio for longer reach without introducing noticeable penalty.

  • 34. Gerschutz, F.
    et al.
    Fischer, M.
    Koeth, J.
    Chacinski, M.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Kjebon, Olle
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Kovsh, A.
    Krestnikov, I.
    Forchel, A.
    Temperature insensitive 1.3 mu m InGaAs/GaAs quantum dot distributed feedback lasers for 10 Gbit/s transmission over 21 km2006In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 42, no 25, p. 1457-1458Article in journal (Refereed)
    Abstract [en]

    Long wavelength monomode InGaAs/GaAs quantum dot (QD) distributed feedback (DFB) lasers with emission wavelength around 1325 ran are presented. Threshold currents below 19 mA for operating temperatures up to 70 degrees C and Output powers of 10 mW at 25 degrees C (6 mW at 70 degrees C) are observed. Error-free 10 Gbit/s transmission over 21 kin fibre with an extinction ratio of 8.5 dB at room temperature (5.1 dB at 70 degrees C) is demonstrated. The low threshold, low temperature sensitivity and high modulation speed were realised using complex coupled DFB lasers with ten stacks of self-organised MBE-grown QD layers and p-type modulation doping.

  • 35. Giuliani, G.
    et al.
    Donati, S.
    Villafranca, A.
    Lasobras, J.
    Garces, I.
    Chacinski, Marek
    Dipartimento di Elettronica, Università di Pavia, Pavia, Italy.
    Schatz, Richard
    Dipartimento di Elettronica, Università di Pavia, Pavia, Italy.
    Kouloumentas, C.
    Klonidis, D.
    Tomkos, I.
    Landais, P.
    Escorihuela, R.
    Rorison, J.
    Pozo, J.
    Fiore, A.
    Moreno, P.
    Rossetti, M.
    Elsasser, W.
    Von Staden, J.
    Huyet, G.
    Saarinen, M.
    Pessa, M.
    Leinonen, P.
    Vilokkinen, V.
    Sciamanna, M.
    Danckaert, J.
    Panajotov, K.
    Fordell, T.
    Lindberg, A.
    Hayau, J. -F
    Poette, J.
    Besnard, P.
    Grillot, F.
    Pereira, M.
    Nelander, R.
    Wacker, A.
    Tredicucci, A.
    Green, R.
    Round-Robin Measurements of Linewidth Enhancement Factor of Semiconductor Lasers in COST 288 Action2007In: Lasers and Electro-Optics, 2007 and the International Quantum Electronics Conference. CLEOE-IQEC 2007. European Conference on, 2007, p. 4385967-Conference paper (Refereed)
    Abstract [en]

    Round-robin measurements on the linewidth enhancement factor are carried out in many laboratories participating to EU COST 288 Action. Up to 7 different techniques are applied to DFB, VCSELs, QCL, and QD lasers, and results are compared.

  • 36.
    Goobar, E.
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Gillner, L.
    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 Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Broberg, B.
    Tanbun-Ek, T.
    Nilsson, S.
    Measurement of a VPE-transported DFB laser with blue-shifted frequency modulation response from DC to 2 GHz1988In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 24, p. 746-747Article in journal (Refereed)
    Abstract [en]

    The frequency modulation characteristics of a VPE-transported 1.53 mu;m wavelength GaInAsP-InP DFB semiconductor diode laser was measured. Below approximately 0.7 mW optical output power per facet, it exhibited a smooth, blue-shifted, frequency modulation response from DC to 2 GHz. In the modulation frequency range of 10 MHz to 100 MHz it exhibited a | Delta;f/ Delta;I| of 0.5-1.8 GHz/mA, depending on the biasing level

  • 37.
    Goobar, E.
    et al.
    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 Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Broadband measurements of frequency noise spectrum in two section DBR laser1991In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 27, p. 289-291Article in journal (Refereed)
    Abstract [en]

    The dependence of the frequency noise on the output power, the tuning current and the current modulation has been measured in a two electrode DBR laser from 30 MHz to 8 GHz. The frequency noise spectrum was fairly flat and decreased with increased output power at a rate faster than 1/P. At certain biasing levels, the noise increased and the relaxation peak was shifted towards lower frequencies when current was injected into the passive waveguide. Furthermore, the frequency noise was not affected by the current modulation.

  • 38.
    Goobar, E.
    et al.
    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 Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Broberg, B.
    Nilsson, S.
    Pure frequency modulation or intensity modulation with suppressed frequency chirp using active Bragg reflector integrated laser1989In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 25, p. 304-305Article in journal (Refereed)
    Abstract [en]

    The modulation properties of a laser structure which consists of an active Bragg reflector (300 mu m) integrated with an uncorrugated gain region (600 mu m) have been measured. The laser exhibited a flat FM response and very low spurious intensity modulation when modulating the current in the Bragg reflector. Furthermore, broadband intensity modulation with suppressed frequency chirp could also be achieved. An inhomogeneous linewidth enhancement factor alpha caused by the uneven carrier density distribution between the two sections gives a qualitative explanation to our results.

  • 39.
    Goobar, Edgard
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Rigole, P.
    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.
    Cross-correlation measurements of intensity noise from the two facets of DFB lasers during linewidth rebroadening1992In: Semiconductor Laser Conference , 1992. Conference Digest. 13th IEEE International, 1992, p. 266-267Conference paper (Refereed)
    Abstract [en]

    Not available

  • 40.
    Goobar, Edgard
    et al.
    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 Applied Physics, MAP. KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Possibilities of large modulation bandwidth of a directly frequency modulated laser with suppressed intensity modulation1989In: Proceedings of 15th European Conference of Optical Communication, 1989Conference paper (Refereed)
  • 41.
    Hong, Xuezhi
    et al.
    KTH, School of Information and Communication Technology (ICT). South China Normal University, China.
    Ozolins, O.
    Guo, C.
    Pang, X.
    Zhang, J.
    Navarro, J. R.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT).
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Jacobsen, G.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). South China Normal University, China.
    1.55-jnm EML-based DMT transmission with nonlinearity-aware time domain super-nyquist image induced aliasing2017In: 2017 Optical Fiber Communications Conference and Exhibition, OFC 2017 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2017Conference paper (Refereed)
    Abstract [en]

    We experimentally demonstrate a DMT transmission system with 1.55-μm EML using nonlinearity-aware time domain super-Nyquist image induced aliasing. Compared with linear equalization, the capacity is improved by ∼16.8%(33.1%) with proposed method for 4(40) km transmission.

  • 42.
    Hong, Xuezhi
    et al.
    KTH, School of Information and Communication Technology (ICT). South China Normal Univ, Peoples R China.
    Ozolins, O.
    Guo, C.
    Pang, Xiaodan
    RISE ACREO AB.
    Zhang, J.
    Navarro, J. R.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Jacobsen, G.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). South China Normal Univ, Peoples R China.
    1.55-μm EML-based DMT transmission with nonlinearity- aware time domain super-nyquist image induced aliasing2017In: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2017Conference paper (Refereed)
    Abstract [en]

    We experimentally demonstrate a DMT transmission system with 1.55-μm EML using nonlinearity-aware time domain super-Nyquist image induced aliasing. Compared with linear equalization, the capacity is improved by ~16.8%(33.1%) with proposed method for 4(40) km transmission.

  • 43.
    Hong, Xuezhi
    et al.
    KTH, School of Information and Communication Technology (ICT). South China Normal Univ, Peoples R China.
    Ozolins, Oskars
    Guo, Changjian
    Pang, Xiaodan
    Zhang, Junwei
    Navarro, Jaime Rodrigo
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). South China Normal Univ, Peoples R China.
    1.55-mu m EML-based DMT Transmission with Nonlinearity-Aware Time Domain Super-Nyquist Image Induced Aliasing2017In: 2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    We experimentally demonstrate a DMT transmission system with 1.55-mu m EML using nonlinearity-aware time domain super-Nyquist image induced aliasing. Compared with linear equalization, the capacity is improved by similar to 16.8%(33.1%) with proposed method for 4(40) km transmission.

  • 44.
    Hong, Xuezhi
    et al.
    KTH Royal Inst Technol, Sch ICT, Kista, Sweden.;South China Normal Univ, ZJU SCNU Joint Res Ctr Photon, Guangzhou, Guangdong, Peoples R China..
    Zhang, Lu
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Pang, Xiaodan
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab). KTH Royal Inst Technol, Sch ICT, Kista, Sweden.;RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Ozolins, Oskars
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Udalcovs, Aleksejs
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Guo, Changjian
    South China Normal Univ, ZJU SCNU Joint Res Ctr Photon, Guangzhou, Guangdong, Peoples R China..
    Nordwall, Fredrik
    Tektronix AB, Stockholm, Sweden..
    Engenhardt, Klaus M.
    Tektronix GmbH, Stuttgart, Germany..
    Kakkar, Aditya
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Rodrigo Navarro, Jaime
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Westergren, Urban
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Jacobsen, Gunnar
    RISE Acreo AB, Networking & Transmiss Lab, Kista, Sweden..
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Xiao, Shilin
    Shanghai Jiao Tong Univ, State Key Lab Adv Opt Commun Syst & Networks, Shanghai, Peoples R China..
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    200-Gbps DMT Transmission over 1.6-km SSMF with A Single EML/DAC/PD for Optical Interconnects at C-Band2017In: 43RD EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC 2017), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    We report on the first experimental demonstration of 200-Gbps (net rate 166.7-Gbps) 1.55-mu m DMT IMDD transmission over 1.6 km fiber using a single monolithically-integrated-EML, DAC and photodiode, achieving an effective electrical spectrum efficiency of 4.93 bit/s/Hz.

  • 45.
    Iglesias Olmedo, Miguel
    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.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Zibar, D.
    Tafur Monroy, I.
    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.
    Digital signal processing approaches for semiconductor phase noise tolerant coherent transmission systems2015In: Proceedings of SPIE - The International Society for Optical Engineering, 2015Conference paper (Refereed)
    Abstract [en]

    We discuss about digital signal processing approaches that can enable coherent links based on semiconductor lasers. A state-of-the art analysis on different carrier-phase recovery (CPR) techniques is presented. We show that these techniques are based on the assumption of lorentzian linewidth, which does not hold for monolithically integrated semiconductor lasers. We investigate the impact of such lineshape on both 3 and 20 dB linewidth and experimentally conduct a systematic study for 56-GBaud DP-QPSK and 28-GBaud DP-16QAM systems using a decision directed phase look loop algorithm. We show how carrier induced frequency noise has no impact on linewidth but a significant impact on system performance; which rises the question on whether 3-dB linewidth should be used as performance estimator for semiconductor lasers.

  • 46. Isaksson, M.
    et al.
    Chacinski, Marek
    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.
    Wesstrom, J. -O
    10 Gb/s direct modulation of 40 nm tunable modulated-grating Y-branch laser2005In: Optical Fiber Communication Conference, 2005. Technical Digest. OFC/NFOEC, 2005, Vol. 2, p. 117-119Conference paper (Refereed)
    Abstract [en]

    High speed properties of a directly modulated widely tunable MG-Y laser have been evaluated. Small signal response and 10 Gb/s NRZ modulation were performed within the 40 nm tuning range.

  • 47.
    Isaksson, Mats
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Chacinski, Marek
    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.
    Wesström, J. -O
    10 Gb/s direct modulation of 40 nm tunable modulated-grating Y-branch laser2006In: OFC/NFOEC Technical Digest, Optical Society of America, 2006Conference paper (Refereed)
    Abstract [en]

    High speed properties of a directly modulated widely tunable MG-Y laser have been evaluated. Small signal response and 10 Gb/s NRZ modulation were performed within the 40 nm tuning range.

  • 48.
    Kakkar, Aditya
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Navarro, J. R.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Louchet, H.
    Pang, Xiaodan
    RISE ACREO AB.
    Ozolins, O.
    Jacobsen, G.
    Popov, Sergei Yu
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Comprehensive study of equalization-enhanced phase noise in coherent optical systems2015In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 33, no 23, p. 4834-4841, article id 7299252Article in journal (Refereed)
    Abstract [en]

    A thorough analysis of equalization-enhanced phase noise (EEPN) and its impact on the coherent optical system is presented. We show with a time-domain analysis that EEPN is caused due to the interference of multiple delayed versions of the dispersed signal, generated by intermixing of the received dispersed signal, and the noise side bands of the local oscillator (LO) in the photodetectors. We derive statistical properties such as the mean, variance, and error vector magnitude of the received signal influenced with EEPN. We show that in coherent optical systems utilizing electronic dispersion compensation, this noise corresponds to multipath fading in wireless communication systems. Closed-form expressions of necessary LO linewidth and/or mitigation bandwidth for a general system configuration and specified OSNR penalty are given. The expressions for system design parameters, validated with system simulations, show that higher order modulation formats, such as 16-quadrature amplitude modulation and beyond, put stringent demands on the LO linewidth unless a mitigation technique is used.

  • 49.
    Kakkar, Aditya
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Navarro, Jaime Rodrigo
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Pang, Xiaodan
    Ozolins, Oskars
    Louchet, Hadrien
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Equalization Enhanced Phase Noise in Coherent Optical Systems with Digital Pre- and Post-Processing2016In: PHOTONICS, ISSN 2304-6732, Vol. 3, no 2, article id 12Article in journal (Refereed)
    Abstract [en]

    We present an extensive study of equalization enhanced phase noise (EEPN) in coherent optical system for all practical electronic dispersion compensation configurations. It is shown that there are only eight practicable all-electronic impairment mitigation configurations. The non-linear and time variant analysis reveals that the existence and the cause of EEPN depend on the digital signal processing (DSP) schemes. There are three schemes that in principle do not cause EEPN. Analysis further reveals the statistical equivalence of the remaining five system configurations resulting in EEPN. In three of them, EEPN is due to phase noise of the transmitting laser, while in the remaining two, EEPN is caused by the local oscillator. We provide a simple look-up table for the system designer to make an informative decision regarding practicable configuration choice and design.

  • 50.
    Kakkar, Aditya
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Navarro, Jaime Rodrigo
    Acreo Swedish ICT AB, Network & Transmiss Lab, S-16425 Kista, Sweden..
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Pang, Xiaodan
    Acreo Swedish ICT AB, Network & Transmiss Lab, S-16425 Kista, Sweden..
    Ozolins, Oskars
    Acreo Swedish ICT AB, Network & Transmiss Lab, S-16425 Kista, Sweden..
    Louchet, Hadrien
    VPI Photon GmBH, D-10587 Berlin, Germany..
    Jacobsen, Gunnar
    Acreo Swedish ICT AB, Network & Transmiss Lab, S-16425 Kista, Sweden..
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Mitigation of EEPN in Coherent Optical Systems With Low-Speed Digital Coherence Enhancement2015In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 27, no 18, p. 1942-1945Article in journal (Refereed)
    Abstract [en]

    A method for mitigating local oscillator (LO) phase noise-induced impairment, also known as equalization-enhanced phase noise, in coherent optical systems is discussed. The method is suitable for real-time implementation and requires hardware with a bandwidth much lower than the signal baud rate, even for a system utilizing conventional semiconductor laser as LO. We evaluate the required parameters like interpolation technique, electrical signal-to-noise ratio at digital coherence enhancement (DCE) front end, for long haul transmission links having quadrature phase shift keying and 16-quadrature amplitude modulation formats. We show that the method can be implemented using a low-speed DCE front end and a simple digital linear interpolator with small (<1 dB) implementation penalty even in cases that would otherwise result in error floor.

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