A Fast Low-Coherent Interferometric Demodulation Method Based on Position-Dependent Dispersion

A technology with low-coherence interference and dispersion characteristics, applied in the field of fast low-coherence interference demodulation, can solve the problems of misjudgment of interference order, step error, inconsistency between peak information and phase information of low-coherence interference fringe envelope, and achieve The effect of high accuracy, increased speed, and simple calculation

Inactive Publication Date: 2015-12-30
TIANJIN UNIV
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Problems solved by technology

This will lead to the inconsistency between the peak information and the phase information of the low-coherence interference fringe envelope, when the inconsistency is greater than , it will lead to misjudgment of the level of interference, resulting in a step error

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  • A Fast Low-Coherent Interferometric Demodulation Method Based on Position-Dependent Dispersion
  • A Fast Low-Coherent Interferometric Demodulation Method Based on Position-Dependent Dispersion
  • A Fast Low-Coherent Interferometric Demodulation Method Based on Position-Dependent Dispersion

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[0041] figure 1 It is a diagram of the low-coherence interference demodulation device based on the position-dependent dispersion characteristic involved in the method of the present invention, and the working process is described in combination with the measurement of the external atmospheric pressure. The demodulation method of the present invention has been verified by experiment, see Figure 2 to Figure 6 .

[0042] Such as figure 1 As shown, the light emitted by the broadband light source (LED) 1 reaches the F-P sensor 3 through the coupler 2. The F-P sensor 3 is a sensitive element that senses the external atmospheric pressure. The two reflective surfaces of the F-P cavity constitute a sensing interferometer. The distance between the two reflecting surfaces of the F-P cavity in the interferometer has a linear relationship with the atmospheric pressure. The optical signal modulated by the F-P sensor 3 is derived from the outlet of the coupler 2 and enters the demodulat...

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Abstract

A fast low-coherence interference demodulation method based on position-dependent dispersion characteristics belongs to the field of optical fiber sensing, specifically relates to the measurement of atmospheric pressure, and is also applicable to measurement fields such as three-dimensional shape detection and optical coherence tomography technology. This method is based on low-coherence interferometry technology, using Fabry-Perot (F-P) sensor as a sensing interferometer, sensing atmospheric pressure through the change of cavity length, and using a demodulator consisting of a polarizer, a birefringent wedge and an analyzer The interferometer demodulates the optical signal modulated by the F-P sensor, and forms spatial low-coherence interference fringes in the local area of ​​zero optical path difference. This method uses the low-precision centroid method to obtain the peak position of the envelope, and calculates the accurate center wavelength interference fringe center fringe peak position and the order of the center fringe according to the system position-related dispersion characteristics and phase shift method, thereby recovering the accurate The zero-order fringe peak position of the central wavelength interference fringe can realize fast and high-precision demodulation of the distance.

Description

technical field [0001] The invention relates to a fast low-coherence interference demodulation method based on position-related dispersion characteristics, belonging to the field of optical fiber sensing. Background technique [0002] Phase-shifting method and low-coherence interferometry are two important distance measurement methods in the field of optical interference, which are widely used in the fields of three-dimensional shape detection, optical coherence tomography and optical fiber sensing, such as pressure and refractive index measurement. The phase shift method has the characteristics of high precision and fast processing speed, but due to the problem of phase ambiguity, its measurement range is limited to Inside, therefore, are commonly used for smooth surface measurements. The low-coherence interferometry can overcome the phase ambiguity problem in the phase-shift method, and theoretically there is no limit to the measurement range. However, the shape of low-...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01D5/26G02F2/00
Inventor 刘铁根江俊峰王双刘琨尹金德石俊锋吴振海张学智
Owner TIANJIN UNIV
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