Low-threshold narrow-linewidth InGaAs-GaAs ridge-waveguide DBR lasers with first-order surface gratings

Abstract

The design and operation of InGaAs-GaAs ridge-waveguide distributed Bragg reflector (DBR) single quantum-well lasers with first-order surface gratings fabricated using only a single growth step are presented. Uncoated devices exhibit CW threshold currents as low as 6 mA with slope efficiencies of 0.46 W/A. By varying the period of the first-order DBR grating, a wavelength range of 540 /spl Aring/ (/spl sim/15.2 THz) is obtained with the threshold currents and slope efficiencies remaining below 10 mA and above 0.40 W/A, respectively, over the entire wavelength range. High characteristic temperature, T/sub 0/, values of 450 K, as measured between T=10/spl deg/C and 40/spl deg/C, are obtained for devices with Bragg wavelengths positively detuned from the peak gain wavelength. The spectral linewidth minimum of these devices is below 25 kHz, which is the resolution limit of the self-heterodyning system used to measure the spectral linewidth.