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Chin-Pang Liu,
V. Polo,
F. Van Dijk,
H. Pfrommer,
M.A. Piqueras,
J Herrera,
A Martinez,
S. Karlsson, O. Kjebon,
R. Schatz,
A. Enard,
Yichuan Yu,
T. Tsegaye,
Chin-Hsiu Chuang,
A.J. Seeds,
J. Marti
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ABSTRACT: A hybrid fiber-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 provides the downstream optical signal modulated not only at the intermediate frequency in the 600- to 900-MHz band for wireline transmission but also at the up-converted frequency in the 5.45- to 5.75-GHz band for wireless transmission. An InGaAsP/InGaAsP multiple-quantum-well asymmetric Fabry-Perot modulator/detector has been designed, fabricated, and packaged and has been employed in the base station (BS) as an optical/electrical transducer, simultaneously providing the functions of optical intensity modulation and photodetection. At the BS, the DOCSIS signals are recovered at the wireline and wireless frequencies for the respective feeding of a cable access network or a fixed wireless access network in a highly flexible approach. Full-duplex operation has been demonstrated for both access types in an indoor laboratory environment. In a subsequent small-scale field trial, real-life Internet traffic provided by a local community antenna television system operator has been transported over the present hybrid fiber-radio access network architecture, and simultaneous transmission of both DOCSIS and digital television signals has also been performed.
Journal of Lightwave Technology 04/2007; 25(3):673-684. · 2.78 Impact Factor
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Yichuan Yu,
S. Karlsson,
C. P. Liu,
R. Schatz,
U. Westergren, O. Kjebon,
C. H. Chuang,
Sailing He,
L. Thylen,
A. J. Seeds,
A. B. Krysa,
J. S. Roberts
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ABSTRACT: The property of intermodulation distortion in a full-duplex radio-over-fibre system with Asymmetric Fabry-Perot Modulator/Detector was investigated. By employing the balanced RF input powers, intermodulation distortion was suppressed and a SFDR of 99dB. Hz<sup>2/3</sup> has been achieved.
Optical Communications, 2006. ECOC 2006. European Conference on; 10/2006
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ABSTRACT: In this paper, the effect of barrier bandgap and composition on the optical performance of 1.55-mum InGaAsP/InGaAsP 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<sub>g</sub>= 1440 to 1260 nm) having different conduction band DeltaE<sub>c</sub> and valence band discontinuity DeltaE<sub>v</sub>, 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 DeltaE<sub>v</sub>. 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
IEEE Journal of Quantum Electronics 08/2006; · 1.88 Impact Factor
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Yichuan Yu,
S. Karlsson,
C P Liu,
R. Schatz,
U. Westergren, O. Kjebon,
C H Chuang,
Sailing He,
L. Thylen,
A.B. Krysa,
J.S. Roberts,
A.J. Seeds
[show abstract]
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ABSTRACT: An InGaAsP multiple-quantum-well asymmetric Fabry-Pe´rot modulator/detector has been developed for radio-over-fiber systems. The measured bandwidth is more than 6 GHz and the total insertion loss is 7.1 dB. The property of nonlinearity and spurious-free dynamic range (SFDR) has been studied theoretically. By optimizing the operation optical wavelength and bias voltage based on the numerical simulation, fifth-order nonlinearity dominates the intermodulation distortion and an SFDR of 101 dB·Hz<sup>4</sup>5/ has been achieved experimentally.
IEEE Photonics Technology Letters 02/2006; 18(9):1040-1042. · 2.19 Impact Factor
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H. Pfrommer,
M.A. Piqueras,
J. Herrera,
V. Polo,
A. Martinez,
S. Karlsson, O. Kjebon,
R. Schatz,
Y. Yu,
T. Tsegaye,
C.P. Liu,
C.H. Chuang,
A. Enard,
F. Van Dijk,
A.J. Seeds,
J. Marti
[show abstract]
[hide abstract]
ABSTRACT: 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-Pe´rot 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.
IEEE Photonics Technology Letters 02/2006; · 2.19 Impact Factor
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ABSTRACT: Long wavelength monomode InGaAs/GaAs quantum dot (QD) distributed feedback (DFB) lasers with emission wavelength around 1325 nm are presented. Threshold currents below 19 mA for operating temperatures up to 70degC and output powers of 10 mW at 25degC (6 mW at 70degC) are observed. Error-free 10 Gbit/s transmission over 21 km fibre with an extinction ratio of 8.5 dB at room temperature (5.1 dB at 70degC) 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
Electronics Letters 02/2006; · 0.96 Impact Factor
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ABSTRACT: We have designed and fabricated air-bridged optical modulator/detectors with modulation bandwidth exceeding 15GHz, the highest yet reported for InGaAsP/InGaAsP MQW AFPMDs. Wavelength dependence of the modulated output power at microwave frequencies is reported for the first time and the wide optical bandwidths (> 17nm) so measured suggest that the AFPMD can be used with low-cost uncooled CWDM lasers in radio-over-fibre applications.
Microwave Photonics, 2005. MWP 2005. International Topical Meeting on; 11/2005
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ABSTRACT: We have fabricated modulator/detectors with modulation bandwidths exceeding 15 GHz, the highest yet reported for InGaAsP/InGaAsP MQW AFPMDs. Wavelength dependence of the modulated output power at microwave frequencies is reported for the first time.
Optical Communication, 2005. ECOC 2005. 31st European Conference on; 10/2005
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ABSTRACT: 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.
Optical Communication, 2005. ECOC 2005. 31st European Conference on; 10/2005
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ABSTRACT: 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.
Advanced Optoelectronics and Lasers, 2005. Proceedings of CAOL 2005. Second International Conference on; 10/2005
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ABSTRACT: 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.
Optical Fiber Communication Conference, 2005. Technical Digest. OFC/NFOEC; 04/2005
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Photonics and Microsystems, 2004. Proceedings of 2004 International Students and Young Scientists workshop; 10/2004
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ABSTRACT: 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.
IEEE Photonics Technology Letters 02/2004; · 2.19 Impact Factor
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ABSTRACT: The directly modulated laser is a simple and reliable source for high speed optical transmission of information. It is especially useful in medium to short distance digital links (e.g. metropolitan and local area networks) where the excess pulse dispersion due to laser chirp is not a critical issue. The linear current to light conversion makes it also interesting for transmission of analogue signals over fiber (CATV and microwave links). In both cases a high bandwidth is needed in order to maximize the transmission capacity and retain good distortion characteristics. For single section DFB lasers with low electrical parasitics, the bandwidth is mainly determined by the differential gain of the active material. There has been little progress in improving this material parameter lately beyond what was achieved with the introduction of strained quantum wells. A theoretical and experimental investigation of another approach to further improve the modulation bandwidth, namely by utilizing the dispersive feedback from a detuned Bragg grating in a DBR laser.
Laser and Fiber-Optical Networks Modeling, 2003. Proceedings of LFNM 2003. 5th International Workshop on; 10/2003
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ABSTRACT: Directly modulated two section 1.55 μm InGaAsP DBR lasers were used for 40 Gb/s error free operation back-to-back and through 1 km of standard single mode fiber. Low drive voltage (2 V<sub>pp</sub>) and low bias current (55-65) mA were used. The results show that directly modulated DBR lasers are potential candidates for low cost short distance links at 40 Gb/s.
Indium Phosphide and Related Materials, 2003. International Conference on; 06/2003
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ABSTRACT: Hydride vapour phase epitaxy is flexible for fabricating buried heterostructure lasers yielding high bandwidth. Its potential for long and short wavelength lasers based on the emerging materials systems GaAs/GaInAs(N)(Sb) and GaAs/AlGaAs, respectively is highlighted. In-situ mesa etching cum immediate regrowth and heteroepitaxy of InP on silicon are additional facilities offered by HVPE.
Lasers and Electro-Optics Society, 2002. LEOS 2002. The 15th Annual Meeting of the IEEE; 12/2002
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ABSTRACT: Detuned loading in directly modulated DBR lasers has been evaluated. IMD3 was measured, yielding a spurious free dynamic range of >103 dB/Hz<sup>2</sup>3/ for frequencies 1-19 GHz with a top value of 116 dB/Hz<sup>2</sup>3/ at 1 GHz.
Microwave Photonics, 2002. International Topical Meeting on; 12/2002
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ABSTRACT: Transmission of 20 Gb/s NRZ over 30 km of standard fiber was accomplished with directly modulated DBR lasers at 1.55 mum. Experiments were performed without dispersion compensation and optical amplification and a negative penalty was observed
Optical Communication, 2002. ECOC 2002. 28th European Conference on; 02/2002
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ABSTRACT: We have investigated the occurrence 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
IEEE Journal of Quantum Electronics 01/2001; · 1.88 Impact Factor
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ABSTRACT: We have observed modulation bandwidth enhancement to 28 GHz and
evidence of reduced chirp, beyond the optimally tuned free running case,
in strongly injection-locked DBR lasers. Bandwidth enhancement occurs
because the total modal photon density depends on the phase between the
master and slave fields, which varies during modulation due to the
dependence of index on carrier density. This results in an increased
coupling between the carriers and photons, giving an effectively higher
differential gain. This effect appears to be stronger than the similar
amplitude-phase coupling that occurs with detuned loading. Chirp
reduction occurs only for very strong injection, which can be explained
by the fact that chirp reduction can only be achieved for modulation
frequencies less than the locking range, which increases with injected
power. For higher frequencies, the chirp reduction due to detuned
loading dominates
Lasers and Electro-Optics, 2000. (CLEO 2000). Conference on; 02/2000
