The effects of pedestal suppression on gain-switched laser sources for 40 Gbit/s OTDM transmission

The MQW DFB grating semiconductor laser (GSL)+ dispersion compensated fibre (DCF) source taken alone exhibits a relatively poor extinction ratio (-20dB) which impairs its potential for use in a 40 Gbit/s optical time domain multiplexing (OTDM) system. However, with the addition of an electroabsorption modulator to suppress the pulse pedestals to better than 30 dB extinction, coherent interference noise is much reduced and the BER performance is greatly improved. This enhanced source shows good potential for 40 Gbit/s OTDM communication.