Abstract: The electro-optic coefficients of ADP crystal have been measured at room temperature using DC voltages.The results are γ63＝8.14±0.1×10-12m/V,γ41＝22.2±0.2×10-12m/V at 632.8nm wavelength and γ63＝8.07±0.1×10-12m/V,γ41＝22.9±0.2×10-12m/V at 488nm wavelength.The value of experiment is in good agreement with literature.

Key words: The electro-optic coefficients of ADP crystal have been measured at room temperature using DC voltages.The results are γ63＝8.14±0.1×10-12m/V,γ41＝22.2±0.2×10-12m/V at 632.8nm wavelength and γ63＝8.07±0.1×10-12m/V,γ41＝22.9±0.2×10-12m/V at 488nm wavelength.The value of experiment is in good agreement with literature.