Abstract

Coherent high-power semiconductor lasers are important for many applications due to their compactness, low-cost, and possible integration with other photonic devices. Several types of semiconductor laser amplifiers have been proposed to increase the output power. Among them, the tapered semiconductor laser amplifier has demonstrated the highest output power and still has a good beam quality [1]. However, filamentation is still formed when the device is operated at a much higher power level. In the tapered amplifier, the linearly tailored gain region serves as the spherical expansion of the wave front. The expansion is not ideal because it does not start from a point source, which unfortunately does not practically exist. We propose that the input aperture with its size close to the wavelength could work like a point source and so significantly improves the output beam quality.

© 1998 IEEE