All-optical packet power equalizer for DPSK signal using nonlinear micro ring resonator

In a packet-switched optical network, the packets arriving at a network node suffer significant power level variation due to varying propagation path lengths and component losses in the transmission paths. For best operation of the optical receiver in the above scenario, an all-optical power equalizer is needed. In this paper an all-optical power equalizer for a constant envelope differential phase-shift-keying (DPSK) system operating at 2.5 Gb/s, using power dependent self-switching effect in a nonlinear micro-ring resonator (MRR) has been proposed. The optical equalizer with a configuration of a cascade of 13 MRR rings has been designed and simulated. The parameters of the all-optical power equalizer are determined by using the genetic algorithm based optimization procedure. The designed all-optical power equalizer performs very well to equalize the received DPSK packets over an equalization range 8 dB.