Single mode laser diode having multilayer dielectric mirror providing in-phase back facet reflection

Abstract

Described are laser diodes, and hard drive devices incorporating laser diodes, that include multilayer dielectric mirrors on the back facets thereof that are constructed to provide a high degree of in-phase reflectivity. Such laser diode constructions can help ensure stable single-mode laser operation, which may be useful in maintaining or increasing high areal density capability recording in heat-assisted magnetic recording applications. The described laser diodes include an encapsulant layer over at least the front and back facet, and a multilayer dielectric mirror disposed over the encapsulant layer at the back facet. The multilayer dielectric mirror includes alternating layers of high and low refractive index material, the high refractive index being higher than that of the encapsulant layer and the low refractive index being lower than that of the encapsulant layer. A layer of the low refractive index material is disposed immediately adjacent to the encapsulant layer. This construction can produce high reflectivity as well as in-phase reflections.