Abstract

RE-doped optical fiber devices have witnessed tremendous progress in the last decade. Multi-kilowatt of continuous-wave output power, with a good beam quality, has already been achieved in Yb-doped fiber lasers (YDFL) in the wavelength region of 1060 – 1100 nm. This has motivated power scaling of YDFL operating at longer wavelengths, especially at 1178 nm. Compact, high power and high brightness source at 1178 nm is of great interest for frequency doubling to 589 nm for laser guidestar application. Different approaches have been proposed to generate long wavelength (1160 – 1180 nm) YDFL, which include core-pumped Yb-doped fiber (YDF) at 1060 nm and simultaneously heating the fiber above 100°C [1], direct diode pumping of Yb-doped double-clad fiber with optimised Q-value of the resonator [2] and solid photonics bandgap fiber [3]. In earlier demonstrations, power scaling at wavelength 1178 nm (and beyond) was limited by the amplified spontaneous emission (ASE), that builds up at the shorter wavelength region, which creates parasitic lasing at high pump power. Here we report the results of an experimental study of YDFL at 1179 nm, where the YDF is core-pumped at 1090 nm and heated at 125°C.

© 2009 IEEE