Monolithically integrated DBR laser, detector, and transparent waveguide fabricated in a single growth step

The monolithic integration of a GaAs-AlGaAs distributed Bragg reflector (DBR) laser with a nonabsorbing grating section, a transparent waveguide, and an absorbing photodetector is reported. Transparent and absorbing segments were defined after growth by vacancy-enhanced quantum-well disordering (VED). Laser output power was 5 mW with a threshold current of 22 mA. Detector current was linearly dependent on the laser output power and the emission from the grating side of the laser could be directly coupled into the detector. The conversion efficiency, defined as the ratio between detector current and laser output power, was 0.47 A/W. Using a comparison with as-grown, SiO₂ -capped and SrF₂-capped devices, both lasers and detectors were not seen to be adversely affected by the anneal required for the VED.