Fig. 1. Experimental setup of OPO based on MgO: PPLN

Fig. 2. The repetition rates and pulse duration of fundamental laser

Fig. 3. Quality factor M² of fundamental laser at 30 kHz

Fig. 4. Relationship between output of idler laser and the repetition rates, power of fundamental laser

Fig. 5. The pulse duration of 3.93 μm idler laser at different repetition rates

Fig. 6. Spectra of idler laser at different temperatures

Fig. 7. Comparison between experimental results and theoretical curve of temperature tuned MgO: PPLN