Abstract

Semiconductor lasers suffer from poor spatial coherence when operated at high powers. Deterioration in spatial coherence has been shown to be induced by carrier-induced self-focusing and temperature variations. Many device structures have been proposed to overcome this problem, including: phased arrays, unstable resonators, integrated-master oscillator power amplifiers and a-DFBs. Whichever solution is preferred, it would be of great benefit to observe the internal optical and temperature distributions under high power operation with a view to further improvement in device performance. In this paper we present an experimental technique which gives detailed information about the optical and thermal distributions within high power semiconductor lasers and show how this information can be used to improve performance of a curved facet unstable resonator.

© 1998 IEEE