1.5 Gbit/s transmission system using FP laser as FSK discriminator/photodetector

An optical FM receiver based on a monoelectrode Fabry-Perot laser, with one antireflection coated facet is reported. The device, biased far above threshold, acts as an FSK discriminator/photodetector. An FSK transmission system, up to 1.5 Gbit/s with -30 dBm sensitivities for 10/sup -9/ BER, has been demonstrated using this laser. The speed is limited by the transmitter FM response and not by the receiver response.<>     

Error-free 10 Gbit/s transmission using individual Fabry-Perot modes of low-noise quantum-dot laser

A comb-generating laser suitable for DWDM application is demonstrated on the basis of a multimode quantum-dot laser. Bit error rate < 10^-13 at 10 Gbit/s external modulation was measured for 10 longitudinal modes owing to low (<0.3% over 0.001-10 GHz) relative intensity noise of each individual mode.     

1.244 Gbit/s 32 channel 121 km transmission experiment using shelf-mounted continuous-phase FSK optical heterodyne system

A 1.244 Gbit/s 32 channel transmission experiment is demonstrated by using a shelf-mounted continuous-phase FSK optical heterodyne system. Stable 121 km fibre transmission is achieved with sensitivity ranging from -45.1 to -44.2 dBm at a bit error rate of 10/sup -9/. This is made possible by employing channel spacing stabilisation, optical tuning and polarisation diversity reception.<>     

FSK heterodyne transmission experiments at 560 Mbit/s and 1 Gbit/s

Optical frequency-shift-keying (FSK) signals are obtained from directly modulated distributed feedback (DFB) semiconductor lasers. Experimental studies of the direct frequency modulation (FM) characteristics of the DFB lasers show a nonuniform FM response due to the competing effects of thermal modulation of the laser active region and carrier density modulation. Equalization of the signal current to the laser is employed to produce a flat FM response from 30 kHz to 1 GHz. Optical FSK transmission and heterodyne detection experiments at 560-Mbit/s and 1-Gbit/s are conducted at a wavelength of 1497 nm. Receiver sensitivities of -39 dBm at 560 Mbit/s and -37 dBm at 1 Gbit/s are obtained. Transmission through 100 km of single-mode fiber at 1 Gbit/s is achieved with no degradation in receiver sensitivity.     

Bipolar optical FSK transmission experiments at 150 Mbit/s and 1Gbit/s

Bipolar direct modulation has been used to overcome the nonuniform low-frequency modulation response of distributed-feedback laser transmitter in optical FSK transmission experiments at 150 Mb/s and 1 Gb/s. The heterodyne receiver sensitivity was -48 dBm for 150 Mb/s and -39 dBm for Gb/s, independently of the pseudorandom pattern length. There was no degradation in receiver sensitivity with transmission through more than 100 km of fiber     

5 Gbit/s optical transmission system experiment employing laser amplifier repeater

The performance of a packaged semiconductor laser amplifier has been investigated for use in an optical transmission system at 5 Gbit/s. With optical filtering at the receiver input only small system penalties were found, as expected from the analysis of the dominant noise contributions.<>     

1 Gbit/s PSK homodyne transmission system using phase-lockedsemiconductor lasers

Homodyne detection of 1 Gb/s pilot-carrier (BPSK) optical signals using phase-locked 1.5 μm external-cavity semiconductor lasers is discussed. After 209 km fiber transmission of a 2¹⁵-1 pseudorandom binary sequence (PRBS), the measured receiver sensitivity is 52.2 dBm or 46 photons/bit. Experimental evidence of the data-to-phase-lock crosstalk that potentially limits the usable ratio of linewidth to bit rate in pilot-carrier PSK homodyne systems is presented     

Distance limits of 10 to 20 Gbit/s FSK transmission on standardfibre

A simple analysis is performed on an FSK transmission system using a high FM efficiency, high bandwidth DFB laser as a simple DFB transmitter and an FM/AM converter as an optical signal processor. It shows that optimum optical processing pushes the transmission limits to 150 km at 10 Gbit/s and to 40 km at 20 Gbit/s     

1 Gbit/s bipolar optical FSK transmission experiment over 121 km offibre

Bipolar direct modulation has been used to overcome the nonuniform low-frequency modulation response of a DFB laser transmitter in a 1 Gbit/s optical FSK transmission system. The heterodyne receiver sensitivity (nP¯) was -39 dBm for a 2²³-1 bit pseudorandom pattern, with no degradation in receiver sensitivity after transmission through 121 km of fibre     

15.8 Gbit/s system transmission experiment using a 5.2 mm longmonolithic colliding-pulse-modelocked quantum well laser diode

A 5.2 mm long monolithic colliding-pulse-modelocked quantum well laser diode is fabricated, which generates 6.4 ps optical pulses at a repetition rate of 15.8 GHz: penalty-free 15.8 Gbit/s transmission demonstrates its potential for ultrahigh-speed optical-time-division-multiplexing and soliton systems     

Time-resolved chirp evaluations of Gbit/s NRZ and gain-switched DFB laser pulses using narrowband Fabry-Perot spectrometer

A compact, easy-to-use, low-cost spectrometer for solving the chirped spectrum of DFB lasers is demonstrated using narrowband Fabry-Perot etalons with resolutions comparable to grating spectrometers. Time-resolved chirp measurements of Gbit/s NRZ and gain-switched DFB laser pulses are presented.<>     

1 Gbit/s optical FSK heterodyne transmission experiment over 100 km of single-mode fibre

A 1 Gbit/s optical FSK modulation/heterodyne detection transmission experiment has been conducted at a wavelength of 1497 nm. The receiver sensitivity is ?37dBm and no degradation is observed after transmission through 100 km of single-mode fibre.     

透射窗口型GaAs/GaAlAs掩埋异质结构激光器

本文通过耦合速率方程组,从原理上分析了扩展半导体激光器调制带宽的三个根本途径,在理论计算的基础上给出本结构激光器的具体设计方案。最后介绍了器件的制作工艺和工作特性。     

2.8 Gbit/s optical soliton transmission employing all laser diodes

2.8 Gbit/s optical soliton transmission is successfully demonstrated using a gain-switched 1.55 mu m distributed feedback laser diode and a Ti:LiNbO/sub 3/ intensity modulator. An Er/sup 3+/-doped fibre amplifier and a Raman amplifier, both pumped by 1.47 mu m laser diodes, are employed to achieve intense optical pulses and fibre-loss compensation, respectively.<>     

1.2 Gbit/s, 52.5 km optical fibre transmission experiment usingOEICs on GaAs-on-InP heterostructure

High-performance, long-wavelength OEICs on a GaAs-on-InP heterostructure were fabricated. For the transmitter OEIC, high-speed operation up to 2.4 Gbit/s was achieved, and a receiver sensitivity as high as -26.0 dBm for a 1.2 Gbit/s NRZ signal was realised for the receiver OEIC. To confirm the usefulness of these OEICs for optical fibre networks, a 1.2 Gbit/s optical fibre transmission experiment was successfully carried out over a 52.5 km span     

FSK heterodyne system experiments at 1.5 ?m using a DFB laser transmitter

140 and 70 Mbit/s FSK heterodyne system experiments are reported using single-filter detection with transmitter laser linewidths of 30 and 60 MHz. The system requirements that must be satisfied to avoid large performance penalties are considered.     

1.244-Gb/s 32-channel transmission using a shelf-mountedcontinuous-phase FSK optical heterodyne system

A total capacity of 40 Gb/s is achieved using a shelf-mounted continuous-phase frequency-shift-keying (CPFSK) optical heterodyne frequency-division-multiplexing (FDM) transmission system with 32 optical channels and a bit-rate of 1.244-Gb/s per channel. For achieving a stable bit-error-rate (BER) characteristics with high-sensitivity, narrow-linewidth laser diodes, a channel-spacing stabilization circuit, and an optical tuner are developed. The obtained sensitivity at a BER of 10^-9 for fiber transmission over 121 km ranges from -45.1 to -44.2 dBm, which is 9.8-10.7 dB lower than the shot-noise-limited sensitivity. The crosstalk penalty is suppressed to within 0.1 dB. The developed system has feasibility achieving a distribution system which can distribute more than 250 HDTV (high definition television) signals or 1250 current-standard TV signals to about 8000 subscribers 10 km from the office, or a 40-Gb/s trunk-line system with a fiber span of more than 50 km     

V-grooved substrate buried heterostructure InGaAsP/InP laser

A V-grooved substrate buried-heterostructure laser emitting at 1.3 ?m wavelength is described. The active layer is buried in the V-shaped groove. A CW threshold current of 10~20 mA is obtained and a far-field pattern free from irregularity and peak shift is realised. Damped relaxation oscillation and stable aging characteristics are obtained.     

100/spl deg/C 10 Gbit/s directly modulated InGaAsP DFB lasers with Ru-doped semi-insulating buried heterostructure

A directly modulated 1.3 /spl mu/m InGaAsP DFB laser with a simple buried structure using Ru-doped semi-insulating InP is presented. The high relaxation oscillation frequency of 10 GHz was obtained at 95/spl deg/C. Clear eye openings under 10 Gbit/s direct modulation were achieved from 0 to 100/spl deg/C.     

All-optical clock recovery of NRZ data at 40 Gbit/s using Fabry-Perot filter and two-section gain-coupled DFB laser

All-optical clock recovery from 40 Gbit/s non-return-to-zero (NRZ) data has been experimentally demonstrated by using a fibre-pigtailed Fabry-Perot filter and a self-pulsing two-section gain-coupled distributed feedback laser. The recovered clock has a measured root-mean-square (RMS) timing jitter of 1.2 ps. Error-free performance has been achieved in back-to-back bit error ratio (BER) tests using the optically recovered clock.