Study On Narrow Linewidth Opos Based On Ppln Crystal

Optical parametric oscillators(OPOs)are very attractive tunable sources of radiation with high power and high repetition rates.The output wavelengths of OPOs cover infrared,visible,even ultraviolet range.For these advantages,there are lots of applications,such as atmospheric monitoring,military and medical care.In the paper,the characteristics of narrow linewidth OPO based on periodically polarized lithium niobate crystal doped with magnesia(PPMgLN)with quasi-phase-matching(QPM)are studied.A nanosecond pulsed laser with a wavelength of 1064nm,repetition rate of 5Khz,pulse duration of 23ns was used to pump the periodically polarized lithium niobate crystal doped with magnesia.In this case,the OPO output wavelength is 1.5?m with conversion efficiency of 6.1%,linewidth of about 0.5nm.The PPLN polarization period is 29.64?m and the output signal wavelength of the OPO can be tuned from 1483nm to 1527nm by controlling crystal temperature.In order to achieve narrow linewidth output,two independent FP etalons composing of double-sided polished silicon wafers are inserted into the OPO cavity.By using the lightwave measurement system(Agilent 8164A),optical transmission properties of silicon wafer FP etalons were analyzed and 2mm and 500?m double-sided polished silicon wafers were used for the intra-cavity filters.The linewidth and conversion efficiency of the OPO are around 0.04nm and 1.6%at the output wavelength of about 1.5?m.