Optical pulse synthesis with three cw semiconductor lasers using nonlinear phase-locking

Abstract

Optical pulse synthesis is demonstrated by superposition of equidistant frequencies from separate single-frequency AlGaAs semiconductor lasers which are phase-synchronized by a nonlinear phase-locking scheme. This is done by phase-locking the second harmonic of a laser frequency to the sum frequency of the other two lasers using homodyne detection. Well-defined optical pulses are generated in both the fundamental infrared and the blue light regions. The pulse synthesis principle is examined with relatively small frequency separations of up to several hundred MHz. This method can be easily extended to extremely wide frequency separations, which results in ultra-short optical pulses with more than THz repetition rates.