All-optical equalizer for bandwidth-limited RSOA to transmit 10 Gbps NRZ and ODB signals in WDM-PON

The finite gain recovery time of the reflective semiconductor optical amplifier (RSOA) causes distortion and pattern dependence at high bit rates in colorless optical network units (ONUs) of WDM passive. optical network (WDN-PON). The all-optical equalizers based on Mach-Zehnder interferometer (MZI) and fiber Bragg grating (FBG) are proposed to improve RSOA bandwidth so that to achieve 10 Gbps upstream transmission. The operating principle of optical equalizer from theoretical calculations and simulation demonstration are analysed in detail. The improved received sensitivity is achieved and the open eye diagram is displayed. With the help of optical equalizer, the pattern dependence is effectively suppressed, which demonstrate the feasibility of FBG and MZI for optical equalizer.