A laser deformograph with optical heterodyning

The high sensitivity, the broad dynamic and frequency bands of laser interferometers-deformographs allow to introduce them efficiently in design of earthquake forecasting systems on the basis of registration of Earth's crust deformations in the zones of tectonic fractures. A laser deformograph is suggested with optical heterodyning in the band of reduced frequencies which excludes some shortcomings of laser deformographs. The optical part of the deformograph is a two-beam two-channel orthogonal interferometer. A part of He-Ne laser radiation is directed by a divider after splitting to an electrooptical modulator which is used for the optical frequency shift.