Investigation On High-speed Optical Transmission And All-optical Signal Processing

Transmission and switching are two major areas in communication systems. In these two areas high-speed optical transmissions and all-optical signal processing (AOSP) techniques are investigated in this thesis.A simple pulse source based on cascaded directly modulated laser (DML) and phase modulator was proposed for the first time, in which the produced chirps by the laser and modulator were managed and then compensated for by dispersion compensation fiber (DCF). Furthermore, by using the method of soliton compression highly stable 1.6-ps short pulses with 84-fs timing jitter were obtained. The linewidth of a 40 GHz monolithic integrated semiconductor modelocked laser diode (MLLD) is investigated. The effect of its operation parameters on linewidth and the resulting performance in a 40 Gbaud DQPSK system is experimentally evaluated.For 100 G Ethernet transmission technology, 107 Gb/s RZ-DPSK transmission over 320 km dispersion-managed fiber and 107Gb/s RZ-DQPSK transmission over 480 km dispersion-managed fiber were demonstrated. In addition, 1 Tb/s PM-RZ-DQPSK transmission over 480 km was demonstrated for the first time.In the researches of periodically poled lithium niobate (PPLN) based all-optical signal processing (AOSP), the all-optical wavelength conversions (AOWC) based on cascaded second harmonic generation (SHG) and difference frequency generation (DFG) in the PPLN waveguide were investigated, including polarization insensitive AOWC of 320 Gb/s RZ-DQPSK signal, 320-km transmission of AOWC for 320 Gb/s RZ-DQPSK signals, single channel AOWC of 535 Gb/s RZ-DQPSK and 1.07 Tb/s PM-RZ-DQPSK. By using mid-span spectral inversion (i.e. optical phase conjugation, OPC), 160 Gb/s RZ-DQPSK signal was transmitted over 110 km SMF without dispersion compensation. By using the PPLN based AOWC, 1×4 WDM broadcasting and 1×3 WDM multicasting for 40 Gb/s RZ-OOK signal were demonstrated. The data transparency of the PPLN based AOWC was demonstrated by the simultaneous AOWC of 80 Gb/s RZ-DQPSK and 40 Gb/s RZ-OOK.In the experiment of optical switches based on the PPLN, a 1.46-ps optical switch at a new wavelength with low conversion efficiency was obtained when the control pulse has a pulsewidth of 1.4 ps. In addition, based on polarization insensitive PPLN subsystem"1 control 3"multi-wavelength optical switches was demonstrated.In the researches of semiconductor optical amplifier (SOA) based all-optical signal processing, 40 Gb/s all-optical serial to parallel conversion (SPC) was demonstrated based on the cross gain modulation (XGM) and cross phase modulation (XPM) in a SOA; the AOWC of 107 Gb/s RZ-DQPSK was demonstrated based on the four wave mixing (FWM) in a SOA; in addition, 107 Gb/s RZ-DQPSK was transmitted over 108 km SMF using optical phase conjugation in a SOA.In the researches of highly nonlinear fiber (HNLF) based all-optical signal processing, the AOWC of 53.5 Gb/s DPSK signal was demonstrated based on parametric amplification in a HNLF and the AOWC also shows amplitude regeneration characteristics.