Evaluation of power penalties caused by feedback noise of distributed feedback laser diodes

Power penalties caused by optical feedback noise of distributed feedback laser diodes were evaluated experimentally and theoretically. It was found that power penalties could be suppressed when the beam-relative intensity noises were reduced to less than -135 dB/Hz at 2 Gb/s. This goal can be satisfied using a commercially available optical isolator that has more than 25-dB isolation in the lasar transmitter. >