Abstract

We describe two distinct methods that provide preferential losses to the high order transverse modes present in broad-ridge quantum cascade lasers. The first of these incorporates intracavity lateral constrictions that are localized near the back facet. In the second method, metal is placed in contact with the sidewalls of the cavity to provide distributed losses along the ridge length. When applied properly, both of these techniques suppress high order transverse modes and result in fundamental or near-fundamental mode operation in broad-ridge devices. Despite relatively small loss in efficiency, increased beam quality produces increased brightness.

© 2018 The Author(s)