Distributed-feedback laser produces single-mode output of 40 mW at 650 nm
Researchers at SDL Inc. (San Jose, CA) have demonstrated short-wavelength distributed-feedback (DFB) lasers with room-temperature performance comparable to that of conventional Fabry-Perot devices. They obtained a continuous-wave (CW) output power of more than 40 mW at 652 nm with both single-spatial- and longitudinal-mode operation; device efficiency and far-field performance was consistent with that of typical Fabry-Perot lasers. According to the group, this is the highest-power and shortest-wavelength, single-contact CW room-temperature single-spatial-mode device demonstrated thus far. The DFB lasers were based on a buried second-order grating in a single-mode gallium indium phosphide/aluminum indium phosphide laser structure. The devices were continuously tunable with current and temperature and exhibited no mode hops. They should, therefore, be useful for applications in which short wavelength and longitudinal-mode stability are required, such as spectroscopy, interferometry, and optical storage. The researchers note that no complex and expensive manufacturing tools, such as electron-beam writing or sophisticated dry etching, was required, which means the devices should be manufacturable at low cost. High-frequency versions of the laser may also be useful for plastic-fiber communication applications in which losses at 680 nm are low.