Chirped comb generation in frequency shifted feedback DFB lasers

Abstract

The optical output of frequency shifted optical feedback lasers can exhibit a chirped structure covering a large continuous range of frequencies. These features can be used in various applications such as optical pumping, high precision optical frequencies measurement and optical frequency domain ranging (OFDR). For the first time, a broadband chirped frequency comb has been generated using a conventional DFB laser diode and an intracavity acoustooptic modulator. The experimental factors that affect the comb characteristics of this compact and robust system have been studied and quantified. The experimental results have also been compared with theoretical predictions and, in general, there is good agreement. The FSF DFB has also been evaluated in a simple OFDR system.