Multi-path optical path correlator with adjustable resonance cavity length

Abstract

The invention belongs to the technical field of optical fibers, and particularly relates to a multi-path optical path correlator with adjustable resonance cavity length, which is applied to a multiplexing optical fiber white light interference sensor array demodulation system. An optical resonance cavity is connected with an optical fiber light path by a coupler, the length of the resonance cavity is adjusted, the multiple travel of the optical path is performed, the multi-path optical path correlator consists of an optical resonance cavity with adjustable optical path, an optical fiber coupler, and a three-port or four-port optical fiber circulator, and the adjustable optical path difference signal can be generated by the reciprocating oscillation of the optical resonance cavity; a light signal containing the multi-path optical path difference is outputted by the coupler; the traveling direction of the light source is controlled by the three-port circulator, and the optical path correlation is performed through the connection with a light path of an optical fiber white light interface system. The multi-path optical path correlator has the advantages that the light path matching of multiple optical paths is realized, the demodulation capability of a sensing system is improved, the light path structure of the optical system is simplified, the system cost is reduced, and the stability and reliability of the system are improved.

Description

technical field [0001] The invention belongs to the field of optical fiber technology, and specifically relates to a multi-path optical path correlator with adjustable resonant cavity length that can be used in a demodulation system of multiplexed optical fiber white light interference sensor array. Background technique [0002] Optical fiber white light interference technology and method is a unique measurement method and sensing technology in the field of optical fiber technology. This specialized technology is used in the study of wide-spectrum optical interference characteristics, absolute deformation optical fiber sensing measurement, the structure of optical waveguide devices and the detection of light wave reflection characteristic parameters, and the measurement and evaluation of optical polarization state transverse coupling in fiber optic gyroscope rings, especially in It is widely used in the aspects of optical tomography of tissue structure and morphology in medi...

AI Technical Summary

Problems solved by technology

Due to the splitting characteristics and optical path symmetry characteristics of the NXM fiber coupler, the above-mentioned optical autocorrelator has two problems: one is that the optical path topology has a large attenuation of the light source power and low light source utilization

Taking the 2X2 fiber optic coupler as an example, only half of the optical signal generated by the light source reaches the sensor array, and half of the optical signal reflected by it is attenuated. As far as the optical path structure disclosed by W.V.Sorin is concerned, theoretically there is only 1 The light source power of / 4 participates in the optical correlation process, and other powers are attenuated. If a 3X3 or 4X4 fiber coupler is used, the power attenuation is (1 / 3)2 or (1 / 4)2, which is more serious ; Instead, there is symmetry in the topological structure of the optical path. The light source and the detector are symmetrical and reciprocal in the optical path. In theory, at least the optical signal with the same value as the received power of the detector is fed back to the light source, although the type of light source It is a wide-spectrum light. Compared with laser light sources, it is not very sensitive to feedback, but excessive signal power feedback will cause resonance of the light source (such as the light source ASE based on the fiber spontaneous super-radiation type, etc.), which will cause the light source to generate optical signals. Especially in the case of white light interference, large interference signal power fluctuations will have an extremely adverse effect on the use of the light source, reducing the measurement accuracy of the optical self-coherence peak amplitude

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