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Sum-Frequency Generation in Periodically Poled KTiOPO4 with Large Tolerances of Temperature and Wavelength

In a sum-frequency generation system based on periodically poled nonlinear optical crystal, a new approach to the expansion of acceptance widths of temperature and wavelength has been demonstrated. By using periodically poled KTiOPO4 (PPKTP), the condition is found theoretically so that the tolerances of temperature and wavelength are enlarged. A temperature acceptance width of 60°C is obtained experimentally by mixing the light of two diode lasers (1590 nm and 808 nm) in a 10-mm-long PPKTP crystal.