Generic J 1…J 4 Method of Optical Phase Detection

Abstract Two new expressions for the linear, direct measurement of dynamic phase shift in a no-feedback, no-phase bias optical homodyne interferometer are presented based on the recent, generic J 1…J 4 technique. These new methods, the J 1…J 6(neg) and the J 1…J 6(pos) schemes, consider the voltage amplitude at the fundamental frequency and the next five harmonics in comparison to the four components utilized for the J 1…J 4 method. With this development, the accuracy and the minimum detectable phase shift (MDPS) are greatly improved by the J 1…J 6(neg) method, while the dynamic range of phase shift is enhanced by the J 1…J 6(pos) method. An excellent agreement between the experimental results and the predicted values based on the 1/f noise model is demonstrated for all the three methods. For the experimental noise factor k of 0·0011 for the particular set-up used, the MDPS is 0·05, 0·175 and 0·2 rad respectively for the J 1…J 6(neg), J 1…J 4 and the J 1 …J 6(pos) methods.