40-GHz pulse train generation using soliton compression of aMach-Zehnder modulator output

We demonstrate 40-GHz soliton pulse train generation using nonlinear compression of the output of a Mach-Zehnder modulator. This source generates transform-limited pulses at twice the RF drive frequency, requires less than V_π drive level, is tunable in wavelength (over the entire EDFA bandwidth), and is tunable in repetition rate     

High-speed pulse generation using a sinusoidally driven Ti:LiNbO3 directional coupler travelling-wave optical modulator

We report the generation of 47 ps (FWHM) optical pulses at a 5 Gbit/s repetition rate using a sinusoidally driven Ti-LiNbO3 directional coupler modulator with travelling-wave electrodes By selective DC bias of the switch, these pulses are obtained without overdriving and without velocity matching of the electrical and optical waves.     

10×30 GHz pulse train generation from semiconductor amplifierfiber ring laser

A multiwavelength, fiber ring laser source, is demonstrated. It generates 10 wavelength channels, simultaneously mode-locked and synchronized at 30 GHz, each producing 7-ps pulses. The mode-locking technique relies on the gain saturation of the semiconductor amplifier from an external optical pulse train to impose the simultaneous mode-locking of the 10 wavelengths     

100-GHz soliton pulse train generation using soliton compression oftwo phase side bands from a single DFB laser

A 100-GHz soliton pulse train, with the potential of very low timing jitter, is generated using soliton compression of the beat signal between two optical carriers. The optical carriers are obtained by optically filtering out the third-order sidebands generated from a single DFB laser and a LiNbO₃ electro-optic phase modulator driven at 16.9 GHz     

A GaAs HBT 16×16 10-Gb/s/channel crosspoint switch

A 16×16 crosspoint switch IC has been designed and implemented in a 2-μm GaAs heterojunction bipolar transistor (HBT) technology. The IC is a strictly nonblocking switch with broadcast capability and asynchronous data paths. The IC has fully differential internal circuitry and is packaged in a custom high-speed assembly. Test results confirmed that the IC achieves a 10-Gb/s/channel (or 160-Gb/s aggregate) capacity, the highest reported to date for a 16×16 crosspoint switch IC     

16×20-Gb/s, 400-km WDM transmission over NZDSF using aslope-compensating fiber-grating module

We demonstrate 16-channel wavelength-division multiplexing transmission over nonzero dispersion-shifted fiber at a per-channel rate of 20 Gb/s. A broad-band dispersion-compensating grating module is used for compensation of dispersion and dispersion slope     

Femtosecond optical pulse generation from a CW laser using anelectrooptic phase modulator featuring lens modulation

We report a novel electrooptic phase modulator featuring lens modulation and its application to the electrooptic chirping compression method for ultrashort optical pulse generation. In the pulse generation experiment, pedestal free optical pulses of 550 fs in width with a 16.25-GHz repetition rate were obtained by the group delay dispersion of a grating pair from a CW Ar laser. Furthermore, the electrooptic chirping compression method with the electrooptic phase modulator featuring lens modulation is applicable to the negative group delay dispersion as well as positive group delay dispersion     

A 16×1 wavelength division multiplexer with integrateddistributed Bragg reflector lasers and electroabsorption modulators

The integrated operation of a 16×1 wavelength-division-multiplexed (WDM) source with distributed Bragg reflector (DBR) lasers and electroabsorption modulators has been demonstrated. By using repeated holographic exposures and wet chemical etching, 16 different wavelengths from 1.544 to 1.553 μm with an average channel spacing of 6 Å are obtained. A high-performance combiner is used to obtain a very uniform coupling into the single-output waveguide, and with the integration of an optical amplifier an average optical power of -8 dBm per channel is coupled into a single-mode fiber     

Performance of eight-channel OEIC p-i-n/HBT receiver array in8×2.5 Gb/s WDM transmission system

The performance of an eight-channel, 2.5 Gb/s OEIC photoreceiver array in an eight-wavelength long-distance WDM testbed is described. The sensitivity penalties due to crosstalk and transmission are measured, and the source of crosstalk is investigated. Channel sensitivities range from -25.4 to -26.2 dBm after transmission through 720 km of standard fiber, with transmission penalties ranging from 0.3 dB to 1.0 dB. When the power in each of seven interfering channels is 5 dB above sensitivity, the maximum crosstalk penalty suffered by an individual channel does not exceed 1 dB. These experiments are the first comprehensive characterization of monolithic receiver arrays for crosstalk performance under multichannel operation in a realistic system environment     

Pulse width tunable subpicosecond pulse generation from an activelymodelocked monolithic MQW laser/MQW electroabsorption modulator

Actively modelocked pulses are generated from a 1.59 μm MQW laser integrated with an MQW electroabsorption modulator driven at the monolithic cavity frequency. The pulse width is controlled from 39 ps to 0.55 ps by changing the inverse bias voltage applied to the electroabsorption modulator and by linear pulse compression using a fibre     

10-GHz 1.3-ps pulse generation using chirped soliton compression in a Raman gain medium

The authors demonstrate a novel pulse compression technique that is capable of producing high-quality 1.3-ps pulses at a repetition rate of 10 GHz. The technique begins with 20-ps pulses carved by a commercially available external modulator and achieves up to 15-fold compression using a combination of phase modulation and distributed Raman amplification. Unlike adiabatic soliton compression, the scheme takes advantage of an exact solution to the nonlinear Schrodinger equation for chirped soliton evolution. As such, high-quality low-pedestal compressed pulses can be produced in a shorter span of fiber than would be needed for adiabatic compression. Because the system uses external modulation, the source is inherently tunable. Furthermore, the degree of pulse compression can be adjusted by varying the amount of Raman gain and phase modulation.     

Thermal interference in a 0.85 μm 8×8 two-dimensionalvertical-cavity surface-emitting laser array

The authors present a study of the thermal interference in a two-dimensional 0.85 μm vertical-cavity surface-emitting laser array. The distance between pixels is 250 μm. The temperature of the centre pixel is found to increase by at least 15°C due to thermal interference when the other pixels are operated near the threshold current     

High repetition rate CW fundamental soliton generation using multisoliton pulse compression in a varying dispersion fibre

A new method is proposed for fundamental soliton train generation from a CW double-frequency signal. This scheme uses multisoliton precompression in a fibre with sharply increasing dispersion followed by adiabatic compression in a dispersion decreasing fibre.<>     

Transform-limited 7-ps optical pulse generation using asinusoidally driven InGaAsP/InGaAsP strained multiple-quantum-well DFBlaser/modulator monolithically integrated light source

A 20-GHz optical pulse train is generated using a sinusoidally driven InGaAsP/InGaAsP strained multiple-quantum-well (MQW) DFB laser/intensity modulator monolithically integrated light source operating at low voltages (from -4- to -5-V DC bias with a 3.2- and 4.0-V peak-to-peak RF signal). An approximately-transform-limited 7-ps-wide optical pulse, with a spectral width of 47 GHz, is obtained     

High-temperature, low threshold current, and uniform operation1×12 monolithic AlGaInAs/InP strain-compensated multiple quantumwell laser array in 1.5 μm

In this paper, we describe the fabrication of a monolithically integrated 1×12 array of 1.5-μm AlGaInAs/InP strain-compensated multiple-quantum-well (MQW) lasers, which has high reliability and highly uniform characteristics in low threshold current, slope efficiency, and lasing wavelength. Besides, each diode on the array exhibits a high characteristic temperature of 88 K and a low slope-efficiency drop of less than 1 dB between 20-80°C and a lasing wavelength of 1510 nm at 20°C and 20 mA. Also, the diode on the array has a maximum resonance frequency of above 8 GHz or 3-dB modulation bandwidth of 12 GHz     

2×10 Gbit/s WDM 1310-nm optical transmission over 63.5-kmstandard single-mode fiber using optical preamplifiers

Twenty Gbit/s transmission over 63.5 km SMF at 1310 nm is reported by using two channel 10 Gbit/s wavelength (de)multiplexing (Δλ=1.5 nm). Two 1310 nm SL-MQW semiconductor optical amplifiers are utilized for loss compensation and sensitivity improvement. For the 1310 nm wavelength domain, a record bitrate x distance product of 1.27 Tbit/s.km has been obtained. Crosstalk penalties are identified, and the feasibility of an extension up to at least four, 10 Gbit/s channels is discussed     

Picosecond pulse generation with ultralow jitter in 1.5-μmmulticontact MQW lasers using Q-switching

High-peak-power picosecond pulses with ultralow jitter of 65 fs (50-500 Hz) have been generated by Q-switching multi-quantum-well (MQW) distributed-feedback (DFB) and Fabry-Perot (FP) multicontact lasers. Peak pulse powers of 80 mW have been measured for pulses having durations of 26 ps and repetition rates of 1.25 GHz     

Uni- and bidirectional 4λ×560 Mb/s transmissionsystems using WDM devices based on wavelength-selective fusedsingle-mode fiber couplers

Four-wavelength-channel wavelength-division multiplexing (WDM) lab transmission system experiments with buried heterostructure (BH) lasers at 1200-, 1240-, 1280-, and 1320-nm wavelengths, all-fiber WDM devices, and 20-km single-mode link fiber at a 560-Mb/s bit rate demonstrated that unidirectional and bidirectional WDM transmission systems could be operated successfully by using all-fiber 4λ multiplexing, 4λ demultiplexing, or 4λ multiplexing/demultiplexing devices with a low insertion loss per wavelength channel (2.1-4.7 dB), enough optical far-end crosstalk attenuation (18-37 dB), and high optical near-end crosstalk attenuation (43-49 dB). It is concluded that the four-wavelength-channel WDM lab transmission system at 560 Mb/s mainly used as a test bed is not representative of future unidirectional trunk WDM systems. Such systems favor distributed feedback (DFB) lasers in the 1500-1560-nm wavelength range where fiber attenuation is lower than in the 1200-1320 nm wavelength range and where 1500-nm DFB lasers with a smaller linewidth do not limit the repeater distance as much because of mode partition noise     

A 40–44 Gb/s 3× Oversampling CMOS CDR/1:16 DEMUX

A CMOS CDR and 1:16 DEMUX fabricated in a low-cost 90 nm bulk CMOS process operates at 40-44 Gb/s and dissipates 910 mW. A quarter-rate hybrid phase-tracking/3times blind-oversampling architecture is used to improve jitter tolerance, reduce the need for high-power CML circuits, and enable frequency acquisition without a reference clock. Input data are sampled using a 24-phase distributed VCO, and a digital CDR recovers 16 bits and a 2.5 GHz clock from 48 demultiplexed samples spanning 16 UI. Conformance to the ITU-T G.8251 jitter tolerance mask (BER <10^-12 with a 2³¹-1 PRBS source) is demonstrated using both an on-chip and an external BERT.     

High-quality optical pulse train generation at 80 Gb/s using a modified regenerative-type mode-locked fiber laser

In this paper, we present an experimental demonstration of a high-quality optical pulse train generation at 80 Gb/s. The successful operation was achieved via two steps. In the first step, an ultrastable 2-ps (FWHM), 40-Gb/s pulse train was generated using the technique of fourth-order rational harmonic mode locking. The mode-locked laser was stabilized using a regenerative-type base-line extraction feedback technique. In the second step, an external fiber loop mirror consisting of several meters of polarization-maintaining fiber was used to double the repetition rate from 40 to 80 Gb/s. The output of the 80-Gb/s pulse train shows very small pulse-to-pulse amplitude fluctuation with good long-term stability.