Abstract

Coherent optical communication systems will require optical sources having narrow linewidths and stable frequencies. It has been reported that reflections can cause frequency pulling of a laser.^1,2 In an optical fiber communication system reflections will arise at optical interfaces, such as those occurring in the coupling region between a laser and a fiber or between a fiber and an integrated optic device. Thus it is important to study the effects of reflections on the frequency stability of lasers. We report measurements of frequency shifts due to changes of phase of reflections from the microlens tip of a single-mode fiber. Frequency shifts as large as 6 GHz were measured for phase changes of Π rad in both a C³ laser³ and a GRECC laser.⁴

© 1985 Optical Society of America