High-Brightness Wavelength-Beam-Combined Eyesafe Diode Laser Stacks
At 1450 nm, we have demonstrated 20-W wavelength-beam-combined output from a 25- element single bar (M<sup>2</sup> ~ 1.9 times 10), and 80-W cw from a 6-bar diode stack (M<sup>2</sup> ~ 36 times 68).
Coherent (phased array) and wavelength (spectral) beam combining compared (Invited Paper)
Significant progress has been recently reported on beam combining of arrays of fiber and semiconductor lasers using both coherent (phased array) and wavelength (spectral) techniques. The choice between these two classes of beam-combining techniques has implications for the degree of control required on the array elements and on the optical system that is using the beam-combined array. Coherent beam combining imposes more stringent requirements on array-element control (spectrum, phase, amplitude, and polarization) than wavelength combining. Also, wavelength-combined systems should degrade more gracefully than coherent systems and require fewer changes to optical systems as the number of elements is varied.
Wavelength beam combining of slab-coupled optical waveguide laser (SCOWL) arrays
A diffraction-limited output beam from a diode bar using slab-coupled optical waveguide laser (SCOWL) arrays is demonstrated. Even at 15-W peak power, the spatial brightness is at least 1 to 2 orders of magnitude higher than any commercially available diode power sources.