Based On Semiconductor Optical Amplifier Polarization Rotation Effect Of All-optical Signal Processing Technology For Basic Research

The rapid progress of optical fiber communication has been changing the society significantly, the working speed of optical networks aims at40Gb/s or as high as100Gb/s. The conventional way that using O/E and E/O don’t adapt to the high speed optical fiber communication systems. In order to overcome the bottleneck of electrical-to-optical and optical-to-electrical conversions, it is natural that people want the signal to be processed in the optical domain directly, such as switching and memory etc. All-optical signal processing technology is widely considered to be a must route towards the future high speed all-optical networks.All-optical signal processing is mainly based on the nonlinear effects in nonlinear materials such as nonlinear fiber and Ⅲ-Ⅴ materials, the all-optical signal processing based on nonlinear fiber require large pump light power and long enough fiber to introduce obvious nonlinear effects, it is not suitable for large scale integrating. All-optical signal processing using semiconductor optical amplifier(SOA) which is made of Ⅲ-Ⅴ materials has been receiving considerable attention because Ⅲ-Ⅴ materials are quite suitable for large scale integrating using VLSI technology that has been widely used. Recently, all-optical signal processing technologies based on nonlinear polarization rotation (NPR) is receiving considerable interest by many research groups and becoming the main approach in all-optical signal processing, for they are of simple structure, less power consumption and easy to be integrated.This dissertation investigates two key functionalities including all-optical sampling and all-optical power based on nonlinear polarization rotation in SOA. For all-optical sampling, simulation realizes analog signal of1GHz to be sampled by sampling pulses with10GHz repeating frequency theoretically and realizes analog signal of500MHz to be sampled by sampling pulses with2.5GHz repeating frequency experimentally. All-optical sampling transfer curve is fitted by a polynomial function to characterize the sampling system. What’s more, holding beam injection with proper power can optimize the sampling linearity. A scheme based on self-induced polarization rotation (SPR) in SOA is proposed to realize optical power equalization of PRBS10Gbit/s RZ (return-to-zero) and NRZ (non-return-to-zero) signals. Simulation results show that power equalization is limited by the slow gain recovery time of SOA and holding beam injection of proper power can dramatically reduce the TE and TM modes gain of SOA, thus accelerate the response for ultra-fast signal. It is observed that both the distortion of RZ signal and the overshoot of NRZ signal due to the slow gain recovery of the SOA can be significantly suppressed. After the power equalization, Extension Ratio (ER) of the output signal can be increased8-10dB for RZ signal and4-6dB for NRZ signal respectively, and both signals reach high quality with the Q factor of eye-diagram over20.