Fabrication and performance of AlGaAs-GaAs distributed Bragg reflector lasers and distributed feedback lasers utilizing first-order diffraction gratings formed by a periodic groove structure

Distributed Bragg reflector (DBR) lasers and distributed feedback (DFB) lasers utilizing diffraction grating formed by deeply etched periodic grooves were fabricated on an InGaAs-GaAs-strained quantum-well active wafer without using a regrowth process. The first-order grooved grating that had a 150-nm period and 800-nm depth was etched from the top surface into the cladding layer on the wafer using electron beam lithography and a reactive beam etching with a mixture of Br₂ and N₂ gas. The dependence of optical properties on the structure of the grooved grating is discussed in terms of an evaluation of the coupling coefficient. The fabricated DBR and DFB lasers exhibit single-longitudinal mode oscillation with output powers of 20 mW (DBR) and 10 mW (DFB) in the measured temperature range between 15°C-55°C. The characteristic temperature T₀ for the threshold current is about 120 K. The slope efficiency is held constant in the measured temperature range. The performance of these DBR and DFB lasers demonstrates that the use of the grooved grating provides wavelength-stabilized lasers with a simple fabrication process