A simple new laser diode array model for thermal interaction analysis

Abstract

A simple new laser diode array model using the boundary element method is presented. This model−which needs few boundary elements and little calculation time−represents a multilayer chip as a single-layer chip and distributed heat sources as a line heat source in the center of an active region, and neglects the grooves between array elements. For three types of laser diode array chips with element spacing greater than 50 μm, the simple model estimates thermal interactions to within 2%. The interactive thermal influence of laser diode array packing density and the number of elements is discussed in terms of this simple model: Submounts and stems with high thermal conductivity are shown to be effective for increasing the number of elements packed within an array chip. With a type-IIa diamond submount, for example, the number of elements packed within a 400-μm width on an array chip can be increased from five elements 100 μm apart to nine elements 50 μm apart without increasing thermal interaction.