Detecting orthogonal signals of interference fringes based on four-quadrant detector

If the angle between the orientation of the interference fringes and the detector’s coordinate axis varies, the four quadrant units may detect different intensity distributions because of their quadrant characteristics, and the intensity of each quadrant unit may have different phase according to the principle of vector superposition of the cosinusoidal interference fringes. Two detected signals from the four quadrant units, whose phase difference is 90°, could always be found by rotating the detector. When the period of interference fringes changes, the corresponding orthogonal signals by rotating the detector are also detected. Theoretical analysis and numerical simulation validate this method’s feasibility and practicity. Compared with the traditional method, this method has advantag