High-receiver sensitivity in 591 Mb/s noncoherent FSK transmission experiments with standard DFB lasers and a phase tunable DFB laser

591-Mb/s noncoherent FSK 2/sup 23/-1 PRBS transmission experiments using two different commercial standard DFB (distributed feedback) lasers and a phase-tunable DFB laser have been carried out. The commercial DFB lasers are modulated with an AMI (alternated mark inversion) code and the phase-tunable DFB laser with a NRZ (nonreturn to zero) code. With an optical filter bandwidth of 2.7 GHz, receiver sensitivities (for a 10/sup -10/ BER) of -38 dBm for the phase-tunable DFB laser and -36 dBm for both standard DFB lasers are achieved. The influence of optical filter bandwidth and modulation index on the BER is also evaluated.<>