Single-mode distributed-feedback 761-nm GaAs-AlGaAs quantum-welllaser

We have developed single-mode distributed-feedback 761-nm GaAs-AlGaAs quantum well lasers as sources for O₂ sensing through laser absorption spectroscopy. Devices containing a 4-μm-wide ridge waveguide exhibit low threshold currents of 25 mA and quantum efficiencies greater than 35% at output powers in excess of 25 mW. The spectral linewidths of these devices are 12.0 MHz at 15 mW. Temperature- and current-tuning rates are 0.06 nm/°C and 0.0075 nm/mA (-3.9 GHz/mA), respectively. The devices display smooth, continuous, single-mode wavelength tuning over a 4.2 nm interval