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Optical Design of Laser Gyroscope

Sep. 14, 2021

The laser gyroscope is a guidance instrument that determines the physical orientation. It is widely used in modern aviation, navigation, aerospace and defense industries. It uses a laser as an azimuth direction finder to measure the rotational angular velocity (Sagnac effect) with the optical path difference. The laser gyroscope is actually an optical oscillator. In the closed optical path, two beams of light emitted by the same light source interfere. By detecting the phase difference or the change of interference fringes, the rotational angular velocity of the closed optical path can be measured.

The basic element of the laser gyroscope is a ring laser, which is composed of a closed optical path made of quartz. It contains mixed gas (helium-neon gas), two optical mirrors with coating and a semi-transparent mirror. Excite the mixed gas with a power source to generate a monochromatic laser. A semi-transparent mirror is used to lead the laser out of the loop. The two oppositely transmitted lasers interfere through the optical mirror. Digital signal proportional to the angular velocity is obtained through a photodetector. In the laser gyroscope, commonly used optical components include concave mirrors, semi-transparent mirrors, right-angle combining prisms and plano mirrors.

Cavity of laser gyroscope

Drill holes in the glass body to provide an optical path for the beam. The material is a body of quartz glass with zero expansion coefficient. The cavity material has special properties, low temperature expansion coefficient, reduces the piezoelectric control amount of the loop length and the temperature sensitivity.

Optical Reflector

The most important component, its function is accurately to change the direction of light movement in the optical path without loss. But the surface of optical mirror is not smooth or the manufactured light model is inconsistent, it will cause scattering. Moreover, due to absorption or transmission, each mirror will cause a part of the loss of laser energy.

Gain medium

The role of the mixture under proper pressure is to ensure that laser light is generated in the cavity, to provide gain to the resonant state of the cavity, and to ensure the resonant state.

As the core component of the aircraft inertial navigation system, laser gyroscopes have been widely used in many fields such as artificial satellites, submarines, navigation and radar. Laser gyroscopes become the main basis for determining orientation in navigation systems. CLZ Precision Optics Co., Ltd. provides precision optical mirrors with different coatings according to application requirements. For more information, please contact