Tunable Mid-Infrared Continuous-Wave Optical Parametric Oscillator Based on Fan-Out Grating PPLN Pumped at 1064 nm

Recently, a variety of mid-infrared (mid-IR) light sources have been developed for use in remote sensing applications such as biomedical sensing, optical radiation measurement, gas sensing, planetary monitoring and defense science [1]. In particular, continuous-wave (cw) optical parametric oscillator (OPO), which is capable of wide wavelength-tuning and has a narrow linewidth, are known to useful in the mid-IR applications. For example, to achieve performance evaluation of mid-IR spectrometer, which is indispensable for the success of the remote sensing applications, it is essential to develop a light source with a wide wavelength tuning bandwidth and a narrow linewidth. However, because of the absorptive property of the PPLN medium at mid-IR, the use of cw OPO based on PPLN has been limited to more than 4.7 μm [2].