Abstract: A fiber optic gyroscope using a low-polarization and polarization-maintaining hybrid light path comprises an optical meter head and a circuit signal processing part, The optical meter head comprises: a light source, a multi-functional integrated optic chip, a detector, a coupler and a fiber coil, wherein the light source is a low polarization light source and single mode fiber pigtail coupling; the input terminal of multi-functional integrated optic chip uses a single mode fiber, and the output terminal of multi-functional integrated optic chip adopts a polarization-maintaining fiber; the input fiber pigtail of the said detector is a single mode fiber; the coupler is a 2×2 polarization independence single mode fiber coupler; the fiber coil is a polarization-maintaining fiber. By adopting the scheme of the low-polarization and polarization-maintaining hybrid light path and the signal processing methods such as all-digital closed loop control and random overmodulation etc.

Abstract: A manufacturing method of a high-reliability optical fiber coupler includes (1) manufacturing the optical fiber coupler by a fused biconical tapering process employing a parallel sintering process, and detecting via a tension test the strength of the optical fiber resulting from the sintering process, securing the strength thereof being greater than or equal to 1N; (2) fixing both ends of the sintered optical fiber coupler in a U-shaped quartz groove via hardening adhesive, and filling inside of the U-shaped quartz groove around the coupling arm at both ends thereof with adhesive to shorten the suspending length of the optical fiber; (3) inserting the U-shaped groove containing the optical fiber coupler into a circular quartz tube, and fixing both ends of the circular quartz tube via hardening adhesive; and (4) sleeving a stainless steel tube around the circular quartz tube, and sealing both ends of the stainless steel tube.