Abstract

The injection of optical radiation from a master oscillator into a diode-laser array provides a means for achieving a single-lobed single-frequency output beam at power levels exceeding 100-mW cw. In our study of injection locking in diode-laser arrays, we used a single-frequency tunable cw dye laser as a master oscillator. This approach provides us with considerable control over the injection wavelength, bandwidth, intensity, and spatial profile. With a commercial ten-element diode-laser array operating at 100-mW output, we observe a single-lobed off-axis far-field beam pattern when a single element at either end of the array is injected at milliwatt power levels. In injection-locking conditions, a diode-laser linewidth of ≤2 MHz and a detuning range of several tens of gigahertz were measured. We also observe an angular scanning (1.2°) of the emission angle of the single-lobed output beam of the diode-laser array as the injection wavelength is varied over 50 GHz. This angular steering capability is of potential importance for the rapid direct pointing and scanning of diode-laser arrays.

© 1985 Optical Society of America