Dual-cavity doubly resonant optical parametric oscillators: demonstration of pulsed single-mode operation

The operating points of pulsed dual-cavity doubly resonant optical parametr ic oscillators have been investigated, taking into account the influence of the optical dispersion. A diagram is proposed to determine the spectral se paration of doubly resonant positions for any optical lengths of both cavit ies. From the analysis of the distribution of doubly resonant coincidences, original conditions for stable single-mode operation are specified. This a pproach is validated by use of a type II phase-matched beta-barium berate c rystal. Frequency stability and tuning characteristics are also reported. T o our best knowledge, this is the first demonstration of single-mode operat ion that uses a dual-cavity doubly resonant optical parametric oscillator i n the nanosecond pulsed regime. (C) 2000 Optical Society of America.