Y-Branch Surface Etched Distributed Bragg Reflector Lasers at 850nm for Optical Heterodyning

Multiple wavelength sources are of interest in optical communications, optical data processing, spectroscopy, and RF and THz generation by optical heterodyning. Our results demonstrate a tunable dual-wavelength source consisting of two surface-etched distributed Bragg reflector (DBR) lasers with outputs combined by a y-branch coupler, suitable for optical heterodyning. The integrated device presented here has the distinct advantages of a wide range of tunability, extending into the terahertz frequency range, as well as a compact design, requiring the use of no external components. While y-branch DBR lasers at 850nm have been previously explored, the devices reported here have a simplified fabrication process, optimized epitaxial structure, and surface etched gratings, which contribute to significant improvement in output power and wavelength tunability.