Modeling and optimization of 1.54 μm double-fused VCSELs for cw operation above room temperature

Abstract

now with Hewlett-Packard, Palo Alto, CA 94304 AB STRACTRecently, continuous wave (cw) operation of 1 .54pm vertical-cavity surface-emitting lasers (VCSELs) up to 33°C ambient temperature has been demonstrated for the first time. These devices employ strain-compensated InGaAsP multi-quantum wells and GaAs/AlGaAs distributed Bragg reflectors that are fused on both sides of the InP spacer. Lasing operation of those double-fused lasers is analyzed using a comprehensive numerical model including thermal finite element simulation, optical transfer matrix analysis, and kp band structure calculations. The simulation of pulsed laser performance measured at different temperatures delivers internal laser parameters. Intervalenceband absorption is found to be the dominating loss mechanism that prevents lasing at higher temperatures. The thermal conductivity of the multilayer mirror is only 33% of the value expected. Optimized lasers with reduced gain offset and with smaller pillar heat generation are simulated exhibiting lasing at higher temperatures. Improved heat sinking by top-down mounting shows the strongest impact leading to cw operation up to 62°C.

Temperature sensitivity of 1.54-μm vertical-cavity lasers with an InP-based Bragg reflector

“…The gain model is based on Fermi's golden rule and 4 4 band structure computations for the strain-compensated MQW active region [12]. Fig.…”