Abstract

Injection-locking of high power diode laser arrays¹⁾ is a powerful means to improve the spectral and spatial quality of high power diode lasers. In our experiments the 45mW output of a single stripe diode laser (SDL 5422) was focussed, for example, into a 20 stripe 1W diode laser array (Siemens 480401). The substantial improvement in beam quality is shown in Fig. 1. The injection-locked array emitts about 80% of the 800mW output power of the free running array in a nearly diffraction limited beam. While, free running, the diode laser array is highly multi-mode with a spectral width of 2-3nm, the injection-locked radiation is single-mode with a spectral width of less than 20MHz. Injection-locking thus improved the spatial power density by a factor of 50 and the spectral power density by 5 to 6 orders of magnitude.

© 1994 Optical Society of America