Reported linewidths for DFB lasers integrated with a passive extended cavity are broader than expected, probably due to a poor optical coupling to the extended cavity. An improved optical coupling can further reduce the linewidth but at the same time degrades the FM response. We report a monolithic integrated DFB laser with high optical coupling to a low-loss extended cavity and an active modulator section. The linewidth is reduced to 1 MHz while a flat FM response is maintained at 0.7 GHz/mA. The performance of this laser is compared to other conventional composite-cavity DFB lasers.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering