Noise Suppression of All-optical OOK Matching System Based on Cascaded Highly Nonlinear Fiber

Noise can reduce the performance of the OOK matching system, leading to matching errors. For correct the errors, this paper applies a cascaded noise suppression structure and places it in the recirculating loop of the OOK matching system. The devices of the noise suppression structure used are mainly highly nonlinear fiber (HNLF), all-optical filter, all-optical multiplexer and erbium-doped fiber amplifier (EDFA). Through the simulation, we demonstrate that after adding the noise suppression structure, the system can obtain correct matching results under the same noise environment. For examples, it can correct errors in 16 bit data sequence matching with 8 bit target sequence when the input optical signal-to-noise ratio (OSNR) is between 22dB and 30dB and the noise figure of amplifier is 4dB.