Abstract

There is an increasing interest in combining large numbers of relatively low-power lasers to produce much more powerful, high-brightness laser beams. Coherent combining and wavelength (spectral) combining¹²²¹²³ are the two main approaches being studied. We have been concentrating on wavelength beam combining with fiber lasers and have previously demonstrated this concept at low power. Here we discuss recent work to extend this idea to a master-oscillator-power-amplifier (MOPA) configuration by adding a power amplification stage to each oscillator fiber and demonstrating recombination at higher powers. The conceptual layout is illustrated in figure 1. Each fiber laser oscillates at a unique wavelength defined by the intra-cavity grating and the transform lens. The common arm between the grating and the high reflector contains spatially overlapped beams from each of the oscillator fibers. A fraction of the power is extracted from each array element with a fiber-coupler to seed individual power amplifiers, each operating at a different wavelength. The amplified beams are then combined with a grating identical to the one in the oscillator cavities.

© 2002 Optical Society of America