OPTICAL PARAMETRIC OSCILLATION IN PERIODICALLY POLED LITHIUM-NIOBATE DRIVEN BY A DIODE-PUMPED Q-SWITCHED ERBIUM FIBER LASER

We describe what is to our knowledge the first nanosecond periodically poled lithium niobate (PPLN) optical parametric oscillator (OPO) driv en by a fiber laser. The source was frequency doubled by a PPLN sample before pumping a second, 20-mm-long, PPLN crystal. The OPO threshold was <10 mu J, with pump depletions of as much as 45% and a tunable sig nal range of 945-1450 nm (1690-4450-nm idler range), We demonstrated 1 30-nm signal tuning by varying the pump wavelength and doubling crysta l's temperature. Also, we achieved 15-nm tuning with all crystals at a constant temperature. The results demonstrate the potential of the fi ber laser:PPLN combination for practical, versatile, and tunable sourc es. (C) 1998 Optical Society of America.