Beam Combining

The Laser Technology and Applications Group has led the laser community in the development of beam-combining techniques, to take the outputs from arrays of lasers and combine them into essentially a single beam with near-ideal propagation characteristics.  Such beam combining is a decades-old problem, but over the past decade, the group has had multiple successes.

Beam CombiningFiber array for laser beam combining.

The approaches include both wavelength beam combining (WBC), similar to wavelength-division multiplexing in fiber optic communications, and coherent beam combining (CBC). These techniques have been applied to fiber lasers, diode lasers, and quantum cascade lasers.

Some of the notable demonstrations include WBC of 100 diode lasers at 50-W output power, CBC of eight 500-W fiber amplifiers, CBC of an array of 47 diode laser amplifiers at 40 W, and CBC of a quantum cascade amplifier array. Our thrusts include continued power and array-size scaling, development of improved control systems, and simplification of beam-combining architectures.

SCOWAImage of slab-coupled optical waveguide double-pass amplifier (SCOWA) arrays in a 2D stack architecture. The stack consists of eleven 21-element array modules creating an 11 x 21 matrix of emitter outputs. Each SCOWA array element within the stack can be electrically addressed individually, allowing for phase control of individual elements via current adjustment. Modules of this design were utilized in coherent beam-combining demonstrations.



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