All-fiber current sensor and polarization state control method thereof

A technology of current sensor and polarization state, which is applied in the field of all-fiber current sensor and its polarization state adjustment, and can solve problems such as little effect

Active Publication Date: 2013-03-13
BEIJING JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Or try to find out the difference between the magneto-optical Faraday effect and the birefringence effect of the fiber itself to suppress the birefringence of the fiber itself, but because the birefringence of the fiber itself is affected by the state of the fiber placement, even for low birefringence fibers, the fiber bends , under the influence of stress and temperature, new birefringence will be formed, so the above methods have little effect

Method used

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  • All-fiber current sensor and polarization state control method thereof
  • All-fiber current sensor and polarization state control method thereof
  • All-fiber current sensor and polarization state control method thereof

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Embodiment 1

[0028] refer to Figure 4 , Figure 4 It is a structural schematic diagram of an embodiment of an all-fiber current sensor based on polarization main state and high-speed polarization state detection in the present invention, including a sequentially connected laser 22, a first polarization controller 24, an optical fiber coil 23, a second polarization controller 25, and a fast polarization State detector 26 and high pass filter 27.

[0029] The difference with the usual all-fiber current sensor is that there is no polarizer at the input end of the fiber coil 23, but a first polarization controller 24 instead; there is no analyzer or polarization beam splitter at the output end of the fiber coil 23 (Wollaston lens, etc.), replaced by a second polarization controller 25 and a fast polarization state detector 26. This is a very simple structure, the key lies in the fast detection of the polarization state and the polarization main state obtained by adjusting two polarization c...

Embodiment 2

[0038] refer to Figure 5 , Figure 5 It is a structural schematic diagram of another embodiment of an all-fiber current sensor based on polarization principal state and high-speed polarization state detection in the present invention, and this embodiment is a structural schematic view of a reflective all-fiber current sensor.

[0039] The figure includes a laser 28 , a first polarization controller 29 , a second polarization controller 30 , a fiber circulator 31 , a fiber coil 32 , a total reflection mirror 33 , a high-speed polarization state detector 34 , and a high-pass filter 35 . The reflective sensor is in Figure 4 On the basis of the above, a total reflection mirror is added at the end of the optical fiber coil 32, so that the light incident on the optical fiber coil 32 returns through the original path, thereby increasing the modulation effect of the magnetic field on the optical signal, which is equivalent to increasing the number of turns of the optical fiber coil...

Embodiment 3

[0043] refer to Figure 6 , Figure 6 It is another structure of an all-fiber current sensor based on the main state of polarization and high-speed polarization detection. The light emitted by the laser 36 is a pulsed light. The first polarization controller 37 is an electric polarization controller, which is composed of a servo system 38 A motorized polarization state control system is developed, which can precisely rotate the polarization state according to the preset requirements when the pulsed light passes through. The output light of the first polarization controller 37 passes through the fiber circulator 39 and enters the fiber coil 40 , where the polarization state is rotated by the Faraday effect in the fiber coil. The light emitted from the optical fiber ring reaches the reflector 41 and returns along the original path after being reflected, passes through the optical fiber ring 40 again, and then passes through the optical fiber circulator 39 to reach the second po...

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Abstract

The invention discloses an all-fiber current sensor and a polarization state control method thereof. The all-fiber current sensor comprises a laser device, a fiber loop assembly for sensing the change of a current magnetic field, a first polarization controller arranged at the input end of the fiber loop assembly, a second polarization controller arranged at the output end of the fiber loop assembly, a fast polarization state detector and a high pass filter which are sequentially arranged. Being different from the all-fiber current sensor in the prior art, the invention has no polarizer and analyzer, but directly detects the change of polarization state on the equator of a Poincare sphere based on the principal state principle and filters temperature interference and other environmental interferences by means of the filter.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to an all-fiber current sensor and a polarization state adjustment method thereof. Background technique [0002] In the power system with high voltage, high current and high power, the traditional electromagnetic current sensor has a series of shortcomings such as susceptibility to electromagnetic interference, low precision, iron core resonance and hysteresis effect, and it is difficult to meet the application requirements. Optical fiber sensors have the advantages of strong anti-electromagnetic interference, good insulation, and large dynamic range. This provides the possibility for the detection of large currents and has received widespread attention. It has become the most popular and most widely used in power systems to detect high-voltage currents. Foreground technology. [0003] The currently developed fiber optic current sensors can be roughly divided into two...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R19/00G01R15/24G02F1/095
Inventor 吴重庆
Owner BEIJING JIAOTONG UNIV
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