Pump-enhanced, continuous-wave, narrow linewidth optical parametric oscillator at 2.9–3.6 μm based on a fan-out PPLN

Abstract

Based on a fan-out grating periodically poled lithium niobate (PPLN), a high efficiency, continuous-wave, narrow linewidth, pump-enhanced optical parametric oscillator (OPO) was demonstrated. This OPO exhibited a broad tuning range of 2890–3574 nm, attributable to the unique properties of the fan-out grating PPLN crystal. The OPO achieved over 3 W output power across 2956–3525 nm, due to pump-enhancement technology and an optimized input coupler, whose transmissivity was optimized based on the efficiency on the tuning range. The maximum output power was 4.06 W at 3014 nm. The signal light was employed for locking, resulting in a standard deviation of idler output power of 0.8% over a duration of 30 min. The linewidth of the idler was measured and estimated to be less than 665 kHz. At the maximum output power at 3238 nm, the M² factors were determined to be 1.25 and 1.33 in the x and y directions, respectively.