SINGLY RESONANT CONTINUOUS-WAVE MODE-LOCKED KTIOPO4 OPTICAL PARAMETRIC OSCILLATOR PUMPED BY A ND-YAG LASER

We present detailed design considerations and performance of a singly resonant cw mode-locked optical parametric oscillator based on KTiOPO4 . The oscillator is synchronously pumped by 2.2-ps, 1.064-mum pulses a t a 75-MHz repetition rate with 4-W average power generated by tempora l compression of pulses from a lamp-pumped mode-locked Nd:YAG laser. W e obtained output pulses 2-3 ps long with hundreds of milliwatts of av erage power from 1.57 to 1.59 mum in the signal branch and from 3.21 t o 3.30 mum in the idler branch. At three times above threshold we meas ured the pulse width of the 1.573-mum signal to be approximately 2.8 p s, and the corresponding spectral width was approximately 1.5 nm, indi cating that the time-bandwidth product is 0.51. The total conversion e fficiency as measured by the pump-pulse depletion is 15%. With active stabilization of the pump laser, the amplitude fluctuation of the osci llator is <15% peak to peak.