Thermal analysis of closely-packed two-dimensional etched-well surface-emitting laser arrays

A self-consistent thermal-electrical model of etched-well surface-emitting GaAs-AlGaAs lasers is applied to study thermal properties of two-dimensional (2-D) arrays. Temperature profiles across small- and moderate-size arrays are generated. Thermal problems associated with integration of vertical-cavity surface-emitting lasers (VCSEL's) into closely packed 2-D arrays are addressed. In particular, thermal crosstalk between elements of the array is investigated. The results indicate severe thermal crosstalk, even at relatively low pumping currents, with strong individual-element temperature-profile nonuniformities. The asymmetry of individual waveguides caused by skewed temperature distributions can be exploited for controlling supermode structure in phase-locked arrays. Optimization of 2-D etched-well laser array designs is presented, aimed at maximizing the optical output power density from the array. We find that the highest output power density is strongly increasing for arrays of small diameter emitters, and that the optimal center-to-center spacing between emitters is equal to /spl sim/2.5-3 times their diameter.>