Long cavity ridge waveguide AlGaAs/GaAs distributed feedback lasers for spectral linewidth reduction

Abstract

Ridge waveguide AlGaAs/GaAs distributed feedback lasers with the cavity length of 820 μm were fabricated. The differential quantum efficiency was as high as 28%, and the power-dependent linewidth was more than an order of magnitude smaller than that of the 290 μm laser, which agrees with theory. The narrowest linewidth was 12 MHz at 6.2 mW.