PHASE-LOCKING OF A SEMICONDUCTOR DIODE-AR RAY IN AN EXTERNAL-CAVITY

Theoretical investigations are reported of the characteristics of high -power lasers with the active medium in the form of a semiconductor di ode array. The selectivity of a Talbot cavity, of a cavity with an asp herical output mirror, and of a semiconfocal cavity is studied as a fu nction of the array parameters. Estimates are obtained of the sensitiv ity of the laser radiation characteristics to fluctuations of the arra y parameters. It is shown that the dependence of the selectivity of an aspherical cavity on these parameters is nearly the same as that of a Talbot cavity, but the fundamental mode propagates without radiation losses between the diodes and beyond the array edges. A semiconfocal c avity is more selective than a Talbot or aspherical cavity. When the n umber of diodes in a linear array exceeds 20, the losses of the second mode in a semiconfocal cavity grow to more than 80%. The efficiency o f a laser with a semiconfocal cavity, calculated ignoring the diode ef ficiency, can reach 80-90%.