Introduction to Laser Gyroscope

Modern gyroscope is an instrument that can accurately determine the orientation of moving objects. It is a widely used inertial navigation instrument in modern aviation, navigation, aerospace, and defense industries. Its development has significant strategic significance for a country's industrial, defense, and other high-tech development. Traditional inertial gyroscopes mainly refer to mechanical gyroscopes, which have high requirements for process structure and complex structure, and their accuracy is constrained by many aspects.

Generally, gyroscopes are divided into laser gyroscopes, fiber optic gyroscopes, micro mechanical gyroscopes, and piezoelectric gyroscopes, all of which are electronic and can be manufactured together with GPS, magneto resistive chips, and accelerometers to form inertial navigation control systems.

Modern fiber optic gyroscopes include interferometric gyroscopes and resonant gyroscopes, both of which were developed based on Sagnik's theory. The key point of Segnik's theory is that when a beam of light travels through a circular channel, if the channel itself has a rotational speed, the time required for the light to travel in the direction of the channel's rotation is greater than the time required to travel in the opposite direction of the channel's rotation.

That is to say, when the optical loop rotates, the optical path of the optical loop will change relative to the optical path of the loop at rest in different directions of advance. By utilizing this change in optical path length, if interference is generated between light traveling in different directions to measure the rotational speed of the loop, an interferometric fiber optic gyroscope can be manufactured. If interference between light continuously circulating in the loop is achieved by adjusting the resonant frequency of the fiber optic loop to measure the rotational speed of the loop, a resonant fiber optic gyroscope can be manufactured.

From this brief introduction, it can be seen that interferometric gyroscopes have a small optical path difference when implementing interference, so the light source they require can have a large spectral width, while resonant gyroscopes have a large optical path difference when implementing interference, so the light source they require must have good monochromaticity.