Engineering topics
Publications and source records attributed to Rutz, E. M..
External cavity for monolithic array of three GaAs lasers phase-coherently couples individual outputs to produce single spatially coherent beam. Fourier transform properties of lens and spatial filter are used to select coherent mode.
Technique for combining outputs of array of small semiconductor lasers increases total output power while relaxing fabrication tolerances to make manufacture potentially less costly. Advantage of free-running mode is that spacing between junction-diode lasers is less critical than for conventional, phase-coherently coupled arrays.
High-radiance gallium arsenide (GaAs) laser operating at room temperature is utilized in optical navigation system. For efficient transformer-to-laser impedance match, laser should be connected directly to pulse transformer secondary winding.
The peak pulse power was increased by operating an array of three homostructure Ga As lasers in the laser device. A spatial filter in the laser device selects the spatially coherent, free running, mode. The optical peak power is 5 watts, which is three times the peak power of a single laser in the array. The far-field distribution of the three laser array is a single Gaussian beam of spatial coherence without sidelobes or grating lobes. The length of the optical pulses of spatial coherence was increased to 200 ns by improved heat transfer from the p-n junctions of the lasers to the metal housing of the pulse transformer, and by doubling the core area and increasing the turns of the primary windings of the pulse transformer. The mechanical stability of the laser device was improved and the transition from mechanical alignment to electro-mechanical alignment control, was facilitated.