Large-measurement-range phase detection method and device based on dual-wavelength phase shift modulation
A phase shift modulation and measurement range technology, applied in the field of large measurement range phase detection, which can solve problems such as phase unpacking distortion and achieve the effect of restoring the true phase
Inactive Publication Date: 2022-08-09
NANTONG UNIVERSITY
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[0004] The purpose of the present invention is to provide a large measurement range phase detection method and device based on dual-wavelength phase-shift modulation, which uses dual-wavelength laser light sources to construct equivalent synthetic wavelengths, effectively solving the problem of single-wavelength systems due to adjacent The absolute difference of the phase value is greater than the phase unwrapping distortion problem caused by π, so as to effectively restore the true phase
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Embodiment 1
[0070] In an embodiment, the wavelength λ of the first laser 1 is 1530nm, the wavelength λ of the second laser 2 is 1550nm, the length difference between the reference arm 7 and the signal arm 8 is 2.8m, the frequency of the rectangular pulse is 1MHz, and the modulated pulse width in one cycle is 28ns. The interferometer produces a standard vibration signal of 50 Hz. Corresponding measuring devices such as figure 1 As shown, the measurement steps are:
[0071] Step 1. Turn on the first laser 1 and the second laser 2, and couple them through the first wavelength division multiplexer. The data sending and receiving module generates a rectangular pulse modulation signal with a frequency of 1MHz, and provides phase modulation with a modulation amount of [0, π / 2] to the phase modulator 5 to form a phase-modulated dual-wavelength laser;
[0072]Step 2. The phase-modulated dual-wavelength laser passes through the 2×2 coupler 6, enters the reference arm 7 and the signal arm 8 at t...
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The invention discloses a large-measurement-range phase detection method based on dual-wavelength phase shift modulation. A phase modulator acts on dual-wavelength laser to generate a phase modulation signal of modulation quantity; the modulated dual-wavelength laser enters a reference arm and a signal arm of the interferometer through a coupler; the light reflected by the Faraday polarization mirror returns to the coupler to generate interference to form dual-wavelength interference light; the dual-wavelength interference light is separated according to the wavelength after passing through a second wavelength division multiplexer and enters a corresponding photoelectric converter; the data sending and collecting module receives two groups of electric signals converted by the photoelectric converter, extracts three-step phase shift signals corresponding to each group and transmits the three-step phase shift signals to the data processing module; the data processing module demodulates the two groups of three-step phase shift signals to obtain two groups of wrapped phase signals, and constructs an equivalent synthesis wavelength by using the wavelengths of the first laser and the second laser; and performing subsequent processing to obtain a final unpacking phase. According to the method, the unpacking error is reduced, large-range phase measurement is realized, and the system performance is effectively improved.
Description
technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a large measurement range phase detection method and device based on dual-wavelength phase shift modulation. Background technique [0002] With the improvement of optical fiber technology, optical fiber sensing technology using optical fiber as the light transmission medium or sensing medium has been vigorously developed, and has been widely used in military, national defense, civil and other fields, contributing to the country's security, stability and economy. development is guaranteed. Optical fiber sensors have a wide range of applications and can be used to measure physical quantities such as pressure, temperature, vibration, and displacement. Compared with traditional electromagnetic sensors, optical fiber sensors have many advantages, such as light weight, strong anti-electromagnetic interference ability, high sensitivity, safety and reliability,...
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IPC IPC(8): G01J9/02
CPCG01J9/02
Inventor 任仲杰马熙圆黄云霞杨晓华高越吴思苗
Owner NANTONG UNIVERSITY