Optimization Of RSOA For Remodulation In WDM-PON

Wavelength Division Multiplexed Passive Optical Network(WDM-PON) is considered as the most promising candidate scheme for the next generation technology to satisfy the ever increasing bandwidth demand. As it reuse lightwave so that colorless Optical Network Unit(ONU) can be realized,the scheme that remodulating downlink signal to generate uplink signal could reduce the cost of WDM-PON construction and maintenance.Reflective Semiconductor Optical Amplifier(RSOA) is one of the attractive schemes to realize colorless ONU because it has large bandwidth and its gain character could provide uplink signal enough optical power.However,there have not been a report of global optimization of RSOA for remodulation in WDM-PON in literature to the best of our knowledge.So this thesis conducts the following research work aiming at the problem:(1)The theoretical model of SOA is studied.Then the simulation program is coded through Matlab according to the theoretical model.The steady and dynamic simulation results are acquired and discussed,emphasizing that using RSOA for remodulation mainly depends on it gain saturation effect.(2)The system architecture of WDM-PON based on RSOA remodulation is built utilizing Optisystem.The complete result of the whole process from transmitting downlink signal to receiving uplink signal are acquire.Based on this,the influence of several RSOA parameters on the receiver sensitivity of uplink signal is studied.The result shows that a global optimal solution which could promote the uplink signal quality can be acquired by optimizing parameters. Meanwhile,the parameters for optimization and their corresponding value ranges are determined.(3)The parameter optimization of RSOA for remodulation in WDM-PON is done through using genetic algorithm to attempt finding the global optimal solution.The optimization is first conducted under the condition of excluding mode confinement factor.The optimization cases are divided into 3 kinds:optimizing device parameters only,optimizing operating conditions only and optimizing both device parameters and operating conditions.The optimization result shows the optimization algorithm adopted by this thesis is effective.(4)The relationship between mode confinement factor and active region thickness is studied.On the basis of introducing this relationship,mode confinement factor is added as a new optimization parameter to the previous parameters and the optimization is conducted once again.The result shows that the influence of mode confinement factor on the optimization result is significant.