Thermal crosstalk in 4 x 4 vertical-cavity surface-emitting laser arrays

We measured thermal crosstalk in 4×4 VCSEL arrays with a 30-μm pitch between devices. The effective thermal resistance of laser diodes in two-dimensional (2-D) arrays is about 50% higher than that of single elements. The output power of the lasers is fairly temperature insensitive under constant voltage operation. From experiments we inferred values for the average thermal conductivity of AlAs-GaAs Bragg reflectors. We found anisotropy in the effective thermal conductivity with numbers of 0.28 W/(cmK) and 0.35 W/(cmK) for the transverse and lateral direction, respectively.