Nonlinear Application Of Semiconductor Optical Amplifier In Optical Fiber Communication

With the development of the semiconductor technology, the performance of semiconductor optical amplifier (SOA) has been improved extremely, and SOA has been studied extensively and applied in many fields. The applications of SOA in optical communication systems can be classified into two aspects: On the one hand, SOA, as the gain implement, has been used as post-amplifier or booster amplifier to increase transmitter laser power, in-line amplifier to compensate losses, and preamplifier to improve receiver sensitivity. On the other hand, based on the non-linearity of SOA such as cross gain modulation (XGM), cross phase modulation (XPM), self-phase modulation (SPM) and four-wave mixing (FWM), it can berealized that wavelength conversion, optical gates, optical logic, and optical clockrecovery, In this paper, in order to describe the affection of the SOA on the pulse, a relativelycomplete model has been used, which includes the gain saturation due to the carrierconsumed, the gain compression induced by intraband process of carrier heating andspectral hole burning, gain asymmetry and shift, position- and time-dependent carrierlifetime.Based on the SOA ring cavity and nonlinear optical loop mirror (NOLM), adesigned scheme for the compression of mode-locked pulse train was been presented.For incident mode-locked pulses with 1mW peak power and 20ps pulse width, thepulse compression factor can exceed 117, and the FWHM of output pulse is less than150fs and the pulse is nearly free pedestal.