FMCW laser interference optical fiber displacement sensor and displacement detection method thereof

Abstract

The invention relates to an FMCW (Frequency Modulated Continuous Wave) laser interference optical fiber displacement sensor and a displacement detection method thereof. The optical fiber displacementsensor includes a single-mode FMCW laser and at least one optical fiber displacement sensing system. The optical fiber displacement sensing system includes an optical circulator, an optical fiber collimator, a partial reflector, a cooperative reflector and a photoelectric detector. The single-mode FMCW laser is connected with an incoming port of the optical circulator through a single-mode opticalfiber or an optical fiber coupler. An adjacent outgoing port of the optical circulator is connected with the optical fiber collimator through a single-mode optical fiber. A third port of the opticalcirculator is connected with the photoelectric detector. The partial reflector is arranged behind the optical fiber collimator. The cooperative reflector is arranged behind the partial reflector. Thecooperative reflector is adhered to the surface of a to-be-detected object and moves along with the object. According to the invention, the optical fiber displacement sensor can acquire a measurementprecision within 10 nm in a large range over a few centimeters, so that precise optical fiber displacement sensing measurement of a large dynamic range is realized.

Description

technical field [0001] The invention relates to the technical field of displacement sensing, in particular to a frequency-modulated continuous wave laser interference optical fiber displacement sensor. Background technique [0002] Displacement sensing is an extremely important measurement and testing technology in scientific research, industry and military fields. Optical displacement sensing technology is especially valued due to its high precision, non-contact, and immunity to electromagnetic interference. Among them, the optical fiber displacement sensing technology has the advantages of small size, light weight, compact structure and flexible form. At present, a variety of optical fiber displacement sensing technologies have been reported, mainly including two types, one is the intensity modulation optical fiber displacement sensor, and the other is the laser interference optical fiber displacement sensor. The intensity-modulated optical fiber displacement sensor is s...

AI Technical Summary

Problems solved by technology

Intensity-modulated optical fiber displacement sensors are simpler in detection methods and signal processing, but have the disadvantages of low precision, poor stability, nonlinear response, and small measurement range.

The laser interferometric optical fiber displacement sensor using the traditional optical zero-beat interferometry technology can achieve very high measurement accuracy, but its measurement accuracy depends on the stability of the laser wavelength, and because the interference signal is a static signal, it is difficult to count fringes. Accurate Displacement Sensing for Large Dynamic Range

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