Abstract

Epitaxially grown waveguides have been shown to be highly efficient laser media. They exhibit exceptionally low threshold owing to their very low losses. Much work has been carried out on longitudinally pumping these devices by a single stripe laser diode leading to output power in the milliwatts range. In order to boost the performances to the multiwatt level, diode bars must be used to pump the laser. Longitudinally pumping of a waveguide by a high power laser diode array is a very difficult task due to the tight geometry of the waveguide (typically 10 μm ×100 μm). On the other hand a typical waveguide offers a long side which is perfectly fitted to the diode bar geometry. Using side pumping one should in principle be able to combine the high efficiency of the waveguide and the high power of the diode bar. Hanna et al demonstrated a side pumped Nd-YAG epitaxial waveguide laser producing up to 20 mW when pumped by a 500 mW, 10 stripes diode array¹. First trials in our lab showed that it is difficult to extend this experiment to higher pump power due to the small dimension of the waveguide. Increasing the thickness of the waveguide leads to multimode operation of the laser and is not always desirable.

© 1995 Optical Society of America