Performance improvement of InGaAs quantum well distributed Bragg reflector laser with curved grating

Abstract

SUMMARYPerformance improvement is performed for an InGaAs quantum well DBR laser consisting of a ridge active channel and a curved grating such that single-mode oscillation with high efficiency and high spectral purity can be realized. The waveguide absorption loss is substantially reduced by selectively disordering the quantum well in the DBR region. The curved DBR grating is optimized so that a high reflectivity and sharp wavelength selectivity are obtained simultaneously. In addition, the external differential quantum efficiency is enhanced by optimizing the reflectivity at the output end with a low-reflection coating. In this approach, a single-mode oscillation is realized with a high external differential quantum efficiency of 0.79 and a side mode suppression ratio of 50 dB. In the laser with a window structure near the output end, resistance to catastrophic optical damage is significantly improved and the maximum output is 294 mW.