METHOD OF MEASURING OPTICAL PHASE DIFFERENCE Russian patent published in 1995 - IPC

FIELD: interference measurements. SUBSTANCE: information and reference beams of coherent radiation are formed for measuring optical phase difference. Interference pattern is then formed and then converted into sequence of electric signals. Then frequency of optical oscillations is smoothly changed of coherent beam till achieving at first minimal and then maximal values of signals of photoelectric conversion. Values achieved are measured and their difference is defined. Signal is formed to be equal to average value by means of changing irradiation frequency. Shift frequency is measured. Average value of the signal is compensated by signal which corresponds to intensity of initial coherent radiation. Then compensating signal is changed for value which excesses over threshold of sensitivity of photoelectric converter. Non-compensation signal is measured. Radiation frequency is shifted additionally for value at which signals of photoelectric conversion are compensated. Frequency of additional shift is measured and phase difference is measured according to mathematic relation where values measured are used. EFFECT: improved precision of measurement. 1 dwg