Long-distance optical fiber vibration detection device and method on basis of Sagnac interference
A long-distance optical fiber and vibration detection technology, which is used in measuring devices, measuring ultrasonic/sonic/infrasonic waves, instruments, etc., can solve the problem of large interference light loss, and achieve the effect of reducing insertion loss
Inactive Publication Date: 2014-01-22
THE 41ST INST OF CHINA ELECTRONICS TECH GRP
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[0007] The invention proposes a long-distance optical fiber vibration detection device and method based on Sagnac interference, which solves the problem of large interference light loss in the long-distance detection of the existing single-ended optical fiber Sagnac interference optical path
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[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.
[0020] Under the premise of satisfying single-ended fiber Sagnac interference, the reason why the interference signal of the existing optical path is very weak mainly comes from the insertion loss of the 3×3 coupler, because the interference optical path requires the continuous optical signal sent by the laser to go back and forth three times through 3×3 coupling The device produces 15dB attenuation, which is a large insertion loss for the inherently weak inter...
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The invention discloses a long-distance optical fiber vibration detection device on the basis of Sagnac interference, which comprises a light source, a photoelectric detector, an optical circulator, a 2*2 coupler and an optical-fiber delay fiber. A laser signal sent out by the light source enters the 2*2 coupler by the optical circulator; the optical signal is divided into two paths at the position of the 2*2 coupler; one path of optical signal A enters an optical fiber to be detected by the optical-fiber delay fiber and a Fresnel reflection optical signal returned from the tail end enters the 2*2 coupler; the other path of optical signal B directly enters the optical fiber to be detected and the Fresnel reflection optical signal returned from the tail end enters the optical-fiber delay fiber by the 2*2 coupler and passes through the optical-fiber delay fiber for one circle to return to the 2*2 coupler; and the optical signal is interfered at the position of the 2*2 coupler and an interference signal is sensed by the photoelectric detector through the optical circulator. Compared with a conventional single-ended interference optical path, a single-ended Sagnac interference optical-fiber optical path of the long-distance optical fiber vibration detection device has the advantage that insertion loss is reduced by about 5dB.
Description
technical field [0001] The invention relates to the technical field of testing, in particular to a long-distance optical fiber vibration detection device based on Sagnac interference, and also relates to a long-distance optical fiber vibration detection method based on Sagnac interference. Background technique [0002] The traditional single-ended optical fiber Sagnac interference optical path is very easy to achieve long-distance detection. The main reasons are: (1) The final interference signal is generated by the Fresnel reflection of the laser on the end face of the optical fiber, which makes the interference light very weak; ( 2) In the traditional single-ended optical fiber Sagnac interference optical path, the laser has to go back and forth through the 3×3 coupler three times, each time the optical signal attenuates 5dB, and the optical signal attenuated by the coupler reaches 15dB, resulting in the interference signal strength again produces a large attenuation. [...
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IPC IPC(8): G01H9/00
Inventor 汪磊李宝瑞魏石磊杨玥暄徐玉华
Owner THE 41ST INST OF CHINA ELECTRONICS TECH GRP