Multichannel synchronous absolute distance measurement method and device based on all-fiber frequency domain interference

An absolute distance, all-optical fiber technology, applied in the direction of measuring devices, optical devices, instruments, etc., can solve the problems of low measurement speed, inability to make full use of light source and spectrometer bandwidth, etc.

Inactive Publication Date: 2020-02-14
INST OF FLUID PHYSICS CHINA ACAD OF ENG PHYSICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If you want to measure multiple distances, you need to introduce an optical path switching device, and because the scanning speed of the spectral splitting mechanism (such as a grating, tunable light source) in a fiber optic spectrometer is generally on the order of millimeters or seconds, while the optical path switching device is on the order of hundreds of milliseconds , so the overall measurement speed is on the order of hundreds of milliseconds, and there are problems that the measurement speed is not high, and the bandwidth of the light source and the spectrometer cannot be fully utilized.

Method used

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  • Multichannel synchronous absolute distance measurement method and device based on all-fiber frequency domain interference
  • Multichannel synchronous absolute distance measurement method and device based on all-fiber frequency domain interference
  • Multichannel synchronous absolute distance measurement method and device based on all-fiber frequency domain interference

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Experimental program
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Embodiment 1

[0040] Embodiment 1 (implemented by a fiber optic circulator, measuring light along the way): refer to figure 2 , the device comprises a broadband light source connected to the incident port of the wavelength division multiplexer 1, the outgoing port of the wavelength division multiplexer 1 is connected to the first port of the fiber optic circulator 2, and the second port of the fiber optic circulator 2 is connected to the fiber probe 3 connection, the third port of the optical fiber circulator 2 is connected to the incident port of the demultiplexer 41, and the outgoing port of the demultiplexer 41 is connected to the fiber optic spectrometer 42 and the computer 5 in sequence.

[0041] The optical fiber circulator 2 adopts a three-port circulator, the light input from the first port is output from the second port, the light input from the second port is output from the third port, and the first port and the third port are highly isolated.

[0042] When the measurement light...

Embodiment 2

[0043] Embodiment 2 (multi-channel measurement light): on the basis of embodiment 1, the output light beam of the broadband light source is divided into n-channel measurement light by wavelength division multiplexer 1 according to the center wavelength and working bandwidth, and then sent to the channel corresponding to The first port of the fiber optic circulator 2 is sent to the fiber optic probe 3 through the second port of the fiber optic circulator 2.

[0044] When the n channels of measuring light pass through the n channels of optical fiber probes, they will return to n channels of reference light and corresponding n channels of probe light. Wherein, in this embodiment, the value of n is greater than or equal to 1 and less than or equal to 8. In addition, the central wavelength interval between channels of the wavelength division multiplexer 1 is 20nm±3nm, the channel isolation is not less than 50dB, the working bandwidth of a single channel is 13nm±1nm, and the central...

Embodiment 3

[0045] Embodiment 3: The optical fiber circulator can also use a four-port optical fiber coupler, the first port of which is directly connected to the second port and coupled to the third port, and the fourth port is directly connected to the third port and coupled to the second port. That is, the combinations that can be formed are: (1) The light input from the first port is output by the second port, and the light input from the second port is output by the fourth port; (2) The light input from the second port is output by the first port. port output, the light input from the first port is output by the third port; (3) the light input from the third port is output by the fourth port, and the light input from the fourth port is output by the second port; (4) the light input from the fourth port is output by the second port; The light input from the four ports is output by the third port, and the light input from the third port is output by the first port; the opposite directio...

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Abstract

The embodiment of the invention provides a multichannel synchronous absolute distance measurement method and device based on all-fiber frequency domain interference, and relates to the technical fieldof absolute distance precision measurement. The method comprises the steps that a broadband light source is divided into n paths of measurement light, and the n paths of measurement light pass through an optical fiber probe and a measurement target and then return to n paths of reference light and corresponding detection light; all the n paths of reference light and the spectrum after the frequency domain interference of the corresponding detection light are integrated, and the light intensity of the light and the spectrum are recorded, wherein Ii(f) is the light intensity after the frequencydomain interference of the n paths of reference light and the corresponding detection light; and segmentation processing is performed on the I(f) to obtain a corresponding power spectrum function Gi(t) so as to obtain an absolute distance between the end surface of the optical fiber probe corresponding to each channel and the surface of a reflector. The absolute distances between the surfaces ofa plurality of measured objects and the light emitting end face of the optical fiber probe can be synchronously measured with high precision, the measurement precision is superior to 5 [mu]m, and themeasurement range can reach 200 mm.

Description

technical field [0001] The present application relates to the technical field of absolute distance precision measurement, in particular, to a multi-channel synchronous absolute distance measurement method and device based on all-fiber frequency domain interference. Background technique [0002] As the first basic physical quantity in physics, distance (or length) has a wide range of uses in the fields of scientific and technological research, engineering applications, and instrument manufacturing, and the measurement of distance involves a wide range. Frequency-domain interferometric ranging technology is a new type of ranging technology. This technology demodulates the frequency-domain interference fringes formed by the interference of two light waves in the frequency domain (light intensity-frequency coordinate system), and obtains the distance between the two beams of light. The optical path difference between. The frequency-domain interferometric ranging technology has ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B11/02
CPCG01B11/026
Inventor 马鹤立陶天炯刘盛刚王翔翁继东康强黄金苗志起何润之叶素华王为陈宏
Owner INST OF FLUID PHYSICS CHINA ACAD OF ENG PHYSICS
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