A high-power (~2W) external-cavity cw diode laser tunable from 960 - 980 nm

Wavelength-tunable high-power diode lasers with narrow-line widths and diffraction-limited outputs are needed for numerous applications including diode-based nonlinear frequency conversion, coherent radar, coherent free-space communications, and spectroscopic applications. The tapered-amplifier gain-guided design [1] has been shown to be a very effective means for achieving high output powers(>1W cw) in a single-lobed diffraction-limited beam [2,3]. Although single longitudinal mode operation using a master-oscillator-power-amplifier (MOPA) scheme, with a monolithic Bragg reflector for the master-oscillator has been demonstrated [4], these structures have very limited tuning ranges (typically < 3 nm), and involve careful adjustment and regulation of the temperature. Broader tuning ranges (~35 nm) of -1 W power levels were demonstrated subsequently by using an external-cavity grating-tuned configuration at wavelengths near 860 nm [5], followed by demonstration of ~0.5 W power levels at other wavelength ranges. This work reports the first demonstration of broadly-tunable narrow-linewidth high-power operation (~1.8W cw, and up to 3 W quasi-cw) in the 960-980 nm wavelength range, to develop a source that is critical for a number of applications including high-power blue generation via quasi-phase matched doubling and spectroscopic study of saturation characteristics of Er-codoped amplifiers and lasers in a variety of host media.