Continuous-wave VCSEL emission reaches 1300 nanometers
Researchers at Gore Photonics (Lompoc, CA) claim to have developed a 1300-nm-output vertical-cavity surface-emitting laser (VCSEL) that meets commercial requirements for data communications. A major problem in achieving long-wavelength operation with previous VCSEL designs has been the need to drive electrical current through the fused wafer interface. The Gore design gets around this problem by placing an 850-nm VCSEL atop a 1300-nm device--the electrically pumped 850-nm VCSEL on top optically pumps the one on the bottom. The 1300-nm VCSEL emits out through the top of the 850-nm laser, although the structure can be designed to emit from either the top or the bottom.
The new laser is based on wafer-fused gallium arsenide/aluminum gallium arsenide mirrors, which have been used in previously reported long-wavelength VCSELs, but the Gore device differs by leaving the mirrors and active regions undoped, in addition to using the 850-nm device as an optical pump. The Gore team reported continuous-wave emission of its device up to 80°C, with an output of 1.3 mW at 25°C, and "virtually all the power in a single longitudinal and transverse mode."