Broad-area flared InGaAs amplifier produces 5-W diffraction-limited CW output at 972 nm
Broad-area flared InGaAs amplifier produces 5-W diffraction-limited CW output at 972 nm
A broad-area flared amplifier that produces 5-W continuous-wave (CW) output at 972 nm in a single-lobed, diffraction-limited far-field pattern was fabricated by Steve O?Brien, Alexander Schoenfelder, and Robert Lang from SDL Inc. (San Jose, CA). According to the researchers, this output is 40% higher than the highest reported power for a narrow-input-aperture indium gallium arsenide (InGaAs) flared amplifier. They say it is also the highest diffraction-limited power ever demonstrated from an all-diode source at any wavelength.
The master oscillator consisted of a high-power tunable laser embodying a flared gain
element operating in an external cavity configuration. Only 0.1?0.2 W of injection power is actually required to operate the flared amplifier efficiently. Tuning of the master oscillator was achieved by rotating a grating until the desired output wavelength was obtained. The master-oscillator output can be single longitudinal mode with a linewidth of less than 10 MH¥and a side-mode suppression greater than 25 dB. The flared amplifiers have shown a 20-nm tuning range while maintaining 3.5 W of diffraction-limited output power.