Tunable single-mode operation of a pulsed optical parametric oscillator pumped by a multimode laser

High-quality single-longitudinal-mode (SLM) tunable signal radiation is gen erated by a pulsed optical parametric oscillator (OPO) pumped by a compact, inexpensive multimode laser. The OPO is based on periodically poled lithiu m niobate (PPLN) in a ring cavity that is injection seeded at its resonated signal wavelength by a single-mode tunable diode laser. Accurate control o f the OPO cavity length and crystal temperature ensures a continuously tuna ble SLM signal output frequency range of >7.5 THz (> 250 cm(-1)); the corre sponding idler output remains multimode. High-resolution molecular spectra are recorded to verify OPO performance at wavelengths of similar to1.55 mum . The observed signal optical bandwidth of less than or equal to 120 MHz (l ess than or equal to0.0040 cm(-1)) compares favorably with that uf a more e laborate PPLN OPO system pumped by a pulsed single-mode laser. (C) 2001 Opt ical Society of America.