The response of a DFB was equalized with a simple RC network for modulating directly its phase and producing a BPSK signal. The system was tested with a heterodyne coherent detector at 1.25 Gb/s and 2.5 Gb/s showing a sensitivity penalty of around 1dB when compared with external phase modulation. The results indicate that the technique could be considered as a reliable low-cost ONU transmitter solution in udWDM-PONs.
Cano, I. [et al.]. Direct phase modulation of a DFB laser for udWDM-PON. A: International Conference on Transparent Optical Networks. "ICTON 2014: 16th International Conference on Transparent Optical Networks: Graz, 6th-10th July, 2014". Graz: Institute of Electrical and Electronics Engineers (IEEE), 2014, p. 1-4.