Abstract

With the increasing need for high power compact laser sources, much attention has been focussed on the Monolithically Integrated Master Oscillator Power Amplifier (MOPA). Such a device has produced power well in excess of 1 Watt.¹ However, reports of filamentation in the flare amplifier has been a persistent source of difficulty with regards to diffraction limited operation. Filamentation has many sources including thermally induced nonlinearities in the index of refraction,² nonuniformities in the input beam,³ dual pass effects,⁴ and spontaneous emission induced nonlinearities. In order to use this device to the fullest potential we must eliminate filamentation. Accordingly, we have identified two different methods by which to suppress filamentation for a single pass amplifier; the use of antiguided structures in the flare amplifier configuration, and the use of pulsed operation in a broad area flared amplifier. Both of these methods can reduce the effects of filamentation if not eliminate them completely without severely compromising the output power. The use of antiguides is an efficient way of eliminating filamentation independent of the time scale under which the filamentation arises. Short pulse ( ~ 6 ps) operation is a method of eliminating filamentation that requires close to 1 ns to arise.

© 1995 Optical Society of America