DIODE-LASER-PUMPED CONTINUOUS-WAVE KTP OPTICAL PARAMETRIC OSCILLATOR

We report on a diode-laser-pumped, noncritically phase-matched, continuous-wave optical parametric oscillator (OPO) based on KTP. The OPO, which consists of a 12-mm-long, x-cut KTP crystal and a linear two-mirror cavity, was pumped by the 769-nm output of a single-stripe GaAlAs diode laser. With a triply (pump-, signal-, and idler-) resonant cavity the pump power at threshold was as low as 6 mW. At a pump power of 74 mW the power of the generated single-mode 1.1-mu m signal wave exceeded 20 mW. The measured spectral width was less than 70 MHz. With a double (pump- and signal-) resonant cavity the OPO's threshold of less that 50 mW was also within the power range of the single-stripe diode laser. With a pump power of 69 mW the signal power was 7.5 mW. Low-threshold operation has also been demonstrated by use of an injection-locked, 200-mu m-wide, 20-stripe GaAlAs diode-laser array as the pump source. These experimental results show the feasibility and the promising aspects of using high-brightness diode lasers as pump sources for efficient, compact, continuous-wave near-infrared OPO systems. (C) 1995 Optical Society of America