DISTRIBUTED FEEDBACK LASER WITH SHORT CAVITY LENGTH

摘要

A distributed feedback laser with a short cavity length, comprising two parts: a gain region (1) and a reflection region (2). In the gain region is provided a metal electrode requiring an injection of current and providing gain to the laser. A grating layer (5) of the gain region comprises a phase region distributed feedback Bragg grating. At one end of the gain region is the reflection region. The reflection region comprises a core layer structure identical to the gain region; that is, a waveguide transmission layer is similarly an active quantum well material; however, the reflection region is not injected with current. The grating layer of the reflection region is a uniformly distributed Bragg grating. An outer end surface of the reflection region is coated with an antireflection film or adopts an antireflective structure so as to reduce reflections. Another end of the gain region is a laser output end surface. The output end surface is coated with an antireflection film so as to reduce reflections. The invention can enable a laser to have a low threshold gain and a good side mode suppression ratio while possessing a short cavity length; the invention is also easy to manufacture.