Among them, the fiber optic gyroscope optical module is the main sensing device for the rotation of the fiber optic gyroscope sensitive carrier, and it is a closed loop formed by the fiber coil and the MIOC. In the case of higher and higher precision requirements, ambient temperature, magnetic field interference and pressure changes will all affect the fiber optic coil, resulting in measurement errors of the fiber optic gyroscope, among which the polarization error is the main error. In the polarization-maintaining fiber optic gyroscope, the traditional method is to splicing the two pigtails of the MIOC to the fiber coil, and the splicing is not ideal as the main polarization cross-coupling point, which leads to large polarization errors. In addition, the welding point is easily affected by external temperature and stress, which will affect the vibration performance and reliability of the gyro. Therefore, it is one of the key technologies of high-precision fiber optic gyroscopes to directly couple the polarization-maintaining fiber coil with the MIOC to form a sensitive coil without the pigtail fusion method.
Direct coupling can reduce two fusion splices, avoid the polarization cross-coupling and backscattecoil and other noise effects introduced by fusion splices, which is beneficial to reduce polarization noise, improve the zero bias stability and repeatability of the fiber optic gyroscope, and reduce the dead zone. , to improve system reliability as a whole. At the same time, it is also beneficial to realize the four-level symmetrical winding method and improve the vibration and temperature performance of the system. Therefore, the direct coupling technology applied to the sensitive coil components is of great significance to the performance improvement and production of fiber optic gyroscopes. It is the first step of direct coupling technology to integrate the optical fiber coil and the MIOC to form a sensitive coil; encapsulating the coupled sensitive coil as a whole is the key guarantee for realizing the coupling technology.
The packaging structure of the optical fiber coil assembly (fiber coil and MIOC) of high-precision fiber optic gyroscope inertial navigation is suitable for the packaging structure of the integrated optical fiber coil assembly in which the optical fiber coil and the MIOC are directly coupled. The high-precision performance requirements are achieved, and the design considers the integrated unitization of the fiber coil and the MIOC, anti-vibration, air tightness, electromagnetic shielding, and heat insulation functions.
The packaging structure of the fiber coil assembly of the high-precision fiber optic gyroscope inertial navigation is suitable for the case where the fiber coil of the main device of the gyroscope and the MIOC are required to be directly coupled (the so-called direct coupling means that the two pigtails at both ends of the fiber coil are directly connected to the MIOC), and In order to achieve high-precision performance requirements, the functions of modular unitization, anti-vibration, air tightness, electromagnetic shielding, and heat insulation are considered in the design. The directly coupled optical fiber coil assembly packaging structure includes a coil support body, a top cover, a thermal insulation layer, an optical fiber coil, a MIOC and an insulating terminal, and the optical fiber coil is directly coupled with the MIOC. The coil support body is an integral structure composed of an annular base plate, a sleeve and a partition plate, the inner circumference of the annular base plate is circumferentially connected with the bottom end of the sleeve, and the outer circumference of the annular base plate in the coil support body is a step edge. The top of the sleeve is closed by a spacer, and the upper surface of the spacer is provided with a MIOC installation groove for installing the MIOC. At least two insulating terminals are installed on the partition; the upper surface of the annular chassis is bonded with a heat insulating layer, and the optical fiber coil is sheathed through the sleeve and bonded on the heat insulating layer. The edge position of the baffle plate is symmetrical with a concave fiber routing slot A and a fiber routing slot B. Both the fiber routing slot A and the fiber routing slot B pass through the MIOC installation slot and the outer wall of the sleeve; the side wall of the sleeve is provided with a fiber outlet hole , after the single pigtail of the MIOC is pierced through the fiber outlet, it is coiled inside the sleeve below the partition plate, and the MIOC signal line is led out by the insulating terminal.
