On-line detection device and on-line measurement method for direct coupling polarization axis alignment between polarization-maintaining fiber ring and y-waveguide

Abstract

The invention discloses a polarization-maintaining optical fiber ring and a Y waveguide direct coupling polarization axis alignment on-line detection device and an on-line measurement method thereof. The polarization axis on-line detection device includes a polarization axis detection device and an image processing module. The polarization axis detection device includes an illumination system, an imaging System and CCD camera; Imaging system includes reflective optical element and objective lens, is used for Y waveguide and polarization-maintaining fiber ring pigtail assembly end face to carry out imaging amplification; Described method comprises: 1), install Y-waveguide and polarization-maintaining fiber ring tail 2) Adjust the imaging system so that the CCD camera can get a clear image; 3) Collect the image to the memory, obtain and calculate the deviation angle between the polarization axis of the Y waveguide and the polarization axis angle of the polarization maintaining fiber ring fiber; The invention acquires the relative position information of the polarization axis during the direct coupling process of the polarization maintaining optical fiber ring and the Y waveguide in real time, can make quantitative evaluation on the final state of the polarization axis alignment, and lays a foundation for further improving the alignment accuracy.

Description

Technical field [0001] The invention belongs to the field of optical fiber sensing, and relates to an online detection device for polarization axis alignment of a polarization-maintaining fiber ring and a Y waveguide directly coupled and an online measurement method thereof. Background technique [0002] The fiber optic gyroscope is an all-solid-state pure optical inertial device. The basic principle is the Sagnac effect and optical reciprocity. The optical path of the fiber optic gyroscope is mainly composed of optical components, polarization-maintaining fiber loops and detectors. Among them, the optical components include broadband light sources, fiber couplers and Y-waveguides; Y-waveguide chips integrate beam splitters, polarizers and broadband phase modulators, which have the functions of light splitting / combining, polarization / analysis and optical phase modulation. It is an important part of the optical path. [0003] At present, the optical path of fiber optic gyroscopes ...

AI Technical Summary

Problems solved by technology

The problem of this Y-waveguide pigtail and polarization-maintaining fiber ring optical fiber connection method is that two fusion points are introduced between the Y-waveguide and the polarization-maintaining fiber ring, which reduces the reliability of the system; at the same time, the presence of fusion points increases the The polarization cross-coupling of the waveguide output channel reduces the detection accuracy of the system; and fusion splicing requires a certain length of fiber, which not only reduces the consistency of the assembly process of the optical path, but also easily destroys the quadrupole symmetry of the fiber ring

[0010] 1. When the first pigtail assembly of the fiber optic ring is coupled with the Y waveguide, if the polarization axis alignment is performed by directly measuring the extinction ratio method, the extinction ratio tester needs to be connected to the polarization maintaining during the coupling process of the fiber optic ring pigtail assembly and the Y waveguide At the other end of the fiber ring, due to the high polarization crosstalk of the polarization-maintaining fiber ring itself, the resolution of the observation results is low, which in turn affects the alignment accuracy of the polarization axis

[0011] 2. When the second pigtail assembly of the fiber optic ring is coupled with the Y waveguide, the optical path formed by the Y waveguide and the polarization-maintaining fiber ring is in a closed state, and the polarization axis alignment operation cannot be completed by detecting the extinction ratio of the output end

[0012] At the same time, the completion of the polarization axis alignment in the existing direct coupling technology depends on the machining accuracy of the fixture and the geometric dimension relationship between the mechanical parts, which makes it impossible to monitor the relative position of the polarization axis of the Y waveguide and the polarization maintaining fiber ring fiber in real time, thus Unable to quantitatively evaluate final state of polarization axis alignment

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