Low noise performance of passively mode locked quantum-dash-based lasers under external optical feedback

Abstract

We report on a systematic investigation of the effect of external optical feedback on 17 GHz passively mode-locked two-section lasers based on InAs/InP quantum dashes emitting at 1.58 μm. Narrowing of mode-beating linewidth down to a record value of ∼500 Hz is demonstrated over a large operating range.