All-Optical Signal Processing Based On Nonlinear Effects In Integrated Devices

All-optical signal processing has been extensively investigated recently as one of the most promising methods for breaking the electrical bottleneck and reducing the power consumption per bit. The desire to meet the high-capacity and cost-effective demands of various communication applications has led to fiber-optic networks with high speed, larger spectral efficiency, and more compatible size. Among those integrated devices for optical signal processing, semiconductor optical amplifiers (SOAs) have several advantages of integration and power saving, while silicon waveguides based on the silicon-on-insulator (SOI) structure have tight mode confinement ability and high nonlinear coefficients. In this thesis, our contributions on all-optical signal processing based on nonlinear effects in both SOA and SOI waveguide is presented.Next generation network systems prefer multi-functional all-optical processing to build effective systems. Simultaneous all-optical amplification, inversion and format conversion based on self-induced nonlinear effects in a single SOA has been performed for10Gb/s nonreturn-to-zero on-off keying (NRZ-OOK) signals. The requirement on the extinction ratio range for the input signals has been improved.All-optical effor-free wavelength conversion, multicasting, and time demultiplexing for OOK signals are performed based on four-wave mixing (FWM) in a SOI waveguide. Continuous and pulse pump are individually employed to compare the quality. Some suggestions are proposed to decrease the noises on the output signal. All-optical error-free wavelength conversion for DPSK signals is also achieved at10Gb/s.Besides, wavelength-division multiplexing and time-division multiplexing, polarization-division multiplexing (PDM) technology has also attracted much attention as one of the effective multiplexing methods to double the spectral efficiency. All-optical polarization demultiplexing, wavelength conversion and multicasting for a20Gb/s (2×10Gb/s) polarization-multiplexed (Pol-MUX) NRZ-OOK signal using FWM in a SOI waveguide are first time presented and realized. The temporal waveforms and eye diagrams demodulated from both polarization channels of the converted idler are clearly observed.All-optical logic gates have been extensively investigated recently as key all-optical signal processing elements to perform various network functions. Several all-optical logic gates based on FWM are first time achieved in SOI waveguide. Simultaneous implementation of logic OR and AND Gates for10Gb/s NRZ-OOK Signals are performed. Besides, all-optical multiple-channel exclusive OR (XOR) gate for10Gb/s NRZ-DPSK signals is realized. Furthermore, we demonstrate a reconfigurable all-optical logic gate for NRZ-PolSK signal at10Gb/s. Either half subtracter (XOR, AB, AB) or XNOR, AND, and NOR logic gates can be implemented simultaneously. The functions of all the three logic gates are experimentally demonstrated using10or40-bit DPSK sequences and the eye diagrams are clearly observed.