Low-frequency intensity fluctuation in laser diodes with external optical feedback

Abstract

Enhanced intensity fluctuations, in particular the low-freqeuncy fluctuation (LFF) component, which appear in a semiconductor laser-diode (LD) output with external optical feedback, can have seriously adverse effects in practical applications when they fall within the signal bandwidth. Experiments have been carried out to determine the mechanism of the LFF enhancement, and a simple relationship between its peak frequency f0 and the basic parameters characterizing an LD with an external reflector have been established. The resuts are in qualitative agreement with the prediction based on a compound cavity laser model.