Abstract

Xerox Palo Alto Research Center. Injection locking has proven a useful means to obtain high power spatially coherent beams in broad area AlGaAs infrared lasers. We have applied the injection locking technique to AlGalnP broad area visible lasers in order to amplify the 647.1 nm line of a krypton ion laser. The AlGalnP laser was 200 pm wide by 750 pm long with uncoated facets. The threshold current density at room temperature was 300 A/cm². The laser amplifier was operated p-side up with 600 ns pulses at 10 kHz. Light was coupled into the amplifier by focusing perpendicularly to the junction and collimating parallel to the junction. The exiting amplified beam had a divergence that was essentially diffraction-limited at 0.18* when the aperture was overfilled and and increasing to 0.22° when the amplifier aperture was underfilled in order to maximize the gain. A maximum single lobe of 167 mW pulsed at a gain of 8.1 dB was obtained at 3.2 times threshold. A maximum gain of 12.1 dB overall was obtained with 46 mW pulsed in a near diffraction-limited single lobe at 3.2 times threshold. Pulsed current operation lead to temporal pulse shape distortion. Further improvements in amplifier operation might be expected from cw injection locking and from traveling wave amplification.

© 1993 Optical Society of America