Theoretical analysis on polarization deviation and switch window optimization in nonlinear optical loop mirror demultiplexer

This paper investigates theoretically two of the dominant issues on nonline ar optical loop mirror (NOLM) demultiplexer: the sensibility to the polariz ation deviation between signal and control pulses and the optimization of t he switch window width. The complete nonlinear Schrodinger equations concer ning the different states of polarization between signal and control lights are firstly established to study the impact of the polarization deviation on the demultiplexed signal. Considering simultaneously the channel crossta lk and the timing jitter between signal and control pulses, the switch wind ow width of NOLM is optimized to achieve the best demultiplexing performanc e. The theoretical analysis shows that the polarization deviation has to be controlled less than 20 degrees within the bit error rate (BER) of 10(-9) s. The optimal amount of the pulse walkoff is a little less than half of th e slot width of the OTDM system.