Performance comparison between direct phase modulated DFB and RSOA for cost effective transmitter in udWDM-PONs

The performance of a directly phase modulated RSOA and an equalized DFB is compared with homodyne coherent detection for udWDM-PONs. Both device produce similar signals but the receiver sensitivity improves by 1.5dB at BER=10
⁻³
with the RSOA because of its flatter phase response and less intensity modulation residual than the DFB.