Evanescently coupled DBR laser arrays in the 760–770 nm wavelength range

Abstract

In this letter, we present evanescently coupled semiconductor laser arrays designed with a distributed Bragg reflector section for spectrally narrow emission and a combined waveguide section for high optical output powers. These devices were designed and fabricated in the AlGaAs material system with an InGaAsP quantum well providing emission in the 760–770 nm wavelength range. Measurements of the light-current characteristics reveal high optical output powers of 600 mW at 20 °C and 700 mW at 5 °C limited by thermal rollover without any signs of a catastrophic optical mirror damage or rapid power degradation. Spectrally narrow emission of 0.2 nm at −3 dB and a high wavelength stability with a small current tuning coefficient of 0.7 pm/mA were found. Far-field investigations reveal pre-dominant coupling of lowest order in-phase supermode emission without any sections for adjusting the phase of the electrical field vector for adjacent elements.