LASER LIGHT SOURCES

摘要

A light source comprises a first laser and a second laser which is arranged so that light from the first laser can be injected into the second. The bias to the lasers is controlled so that the first laser acts as an oscillator and the second laser as a modulator, the output from the modulator being a single longitudinal mode. A low frequency signal is applied to the first laser and detected in the output of the second laser. A phase sensitive detector is responsive to the sensed signal to provide a feedback signal for the second laser such that the cavity modes of the two lasers are aligned automatically.