History of Distributed Feedback Laser

The Internet has become indispensable to our daily lives as social infrastructure. It is obvious that the low loss and wide-band optical fiber contributes to support the increase of the network capacity. However, large capacity networks cannot be realized only with an optical fiber. In particular, a distributed feedback laser (DFB-LD) is indispensable as a light source for high-bit rate and long-haul optical communications systems. This paper reviews the development of DFB-LDs and the optical fiber communications systems based on DFB-LDs.