Abstract: The invention relates to laser diode arrays having high beam quality and high beam brightness. In one approach, a laser diode array package includes a mount and first and second laser diode arrays disposed on the mount. Each of the laser diode arrays defines an optical axis and has an emitting surface lying in an emitting surface plane. The emitting surface plane of the first laser diode array is displaced relative to the emitting surface plane of the second laser diode array in a direction parallel to one of the optical axes. The optical axes of the first and second laser diode arrays are offset from each other in a direction perpendicular to one of the optical axes. First and second lenses are disposed relative to respective emitting surfaces to reduce divergence of light output from the emitting surfaces. In another approach, laser diode array bars are stacked and the individual output beam from each bar is collimated using a short focal length, low aberration lens.

Abstract: A optical medium, such as an angled distributed reflector, e.g., an angular grating, or .alpha.-DFB laser diode or a waveguide wavelength selective filter, has a mean optical axis defining an optical cavity for substantially confined light propagation within the device. An angular grating is provided in at least a portion of the optical cavity forming a grating region permitting light to propagate along the optical cavity in two coupled waves or modes incident along the angular grating, a first incident propagating wave substantially parallel with respect to the mean optical axis and a second incident propagating wave at an angle with respect to the mean optical axis.

Abstract: An optical gain medium comprising, for example, an optical semiconductor device which is differentially pumped and a master oscillator power amplifier (MOPA) device employing such an amplifier. The gain medium may have a linear stripe region or a diverging stripe region that allows the light propagating therein to diverge along at least part of its length, such as a flared or tapered amplifier having a gain region that increases in width toward its output at a rate that equals or exceeds the divergence of the light. The amplifier is pumped with a current density at its input end which is smaller than the current density used to pump the output end for maintaining coherence of the beam to high power levels employing differential pumping.