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Interference type fiber optic current sensor based on magneto-optic modulation

A technology of magneto-optic modulator and fiber optic current, applied in voltage/current isolation, measuring current/voltage, instruments, etc., can solve the problem of modulation frequency reduction and achieve the effect of reducing technical difficulty

Active Publication Date: 2013-07-10
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the Faraday magneto-optic modulation is non-reciprocal, it does not require a very long polarization-maintaining fiber delay line, and the modulation frequency can be greatly reduced

Method used

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  • Interference type fiber optic current sensor based on magneto-optic modulation
  • Interference type fiber optic current sensor based on magneto-optic modulation
  • Interference type fiber optic current sensor based on magneto-optic modulation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Embodiment one: see figure 2 . This interferometric fiber optic current sensor based on magneto-optical modulation is a complete "circular" polarization maintaining open-loop fiber optic current sensor, including broadband light source 1, fiber optic coupler 2, optical fiber "circular" polarizer 3, and "circular" polarization maintaining fiber Coupler 4 , fiber optic magneto-optical modulator 5 , “circular” polarization-maintaining transmission cable 6 , sensing fiber ring 7 , photodetector 11 and signal processing unit 10 . After the broadband light source 1 passes through the fiber coupler 2, it is connected to the input end of the optical fiber "circular" polarizer 3, and the output end of the "circular" polarizer 3 is connected to an input end of the "circular" polarization-maintaining fiber coupler 4 connected; one output end of the "round" polarization maintaining fiber coupler 4 is connected to one end of the "round" polarization maintaining transmission cabl...

Embodiment 2

[0023] Embodiment two: see image 3 . This interferometric fiber optic current sensor based on magneto-optical modulation is a complete "round" polarization maintaining closed-loop fiber optic current sensor, including broadband light source 1, fiber coupler 2, fiber "circular" polarizer 3, and "circle" polarization maintaining fiber coupler 4. Optical fiber magneto-optical modulator 5, "round" polarization maintaining transmission optical cable 6, sensing optical fiber ring 7, photodetector 11 and signal processing unit 10. In this embodiment, a closed-loop circuit is used to replace the open-loop circuit in Embodiment 1, that is, the photoelectric conversion unit in the signal processing unit 10 feeds back the signal related to the detected primary current to the modulation signal generator 9, and the feedback signal output.

Embodiment 3

[0024] Embodiment three: see Figure 4. This interferometric fiber optic current sensor based on magneto-optical modulation is a partial "circular" polarization maintaining open-loop fiber optic current sensor, including broadband light source 1, fiber optic coupler 2, fiber "line" polarizer 13, and "line" polarization maintaining fiber Coupler 14 , optical fiber quarter-wave plate 12 , optical fiber magneto-optic modulator 5 , “circular” polarization-maintaining transmission optical cable 6 , sensing optical fiber ring 7 , photodetector 11 and signal processing unit 10 . After the broadband light source 1 passes through the fiber coupler 2, it is connected to the input end of the optical fiber "line" polarizer 13, and the output end of the optical fiber "line" polarizer 13 is connected to an input of the "line" polarization-maintaining fiber coupler 14 One output end of the "line" polarization-maintaining fiber coupler 14 is connected with the "circular" polarization-maint...

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Abstract

The invention discloses an interference type fiber optic current sensor based on magneto-optic modulation. The interference type fiber optic current sensor based on the magneto-optic modulation comprises a broadband light source, a fiber optic polarizer, a fiber optic coupler, a Faraday magneto-optic modulator, a round polarization-maintaining transmission optical cable, a sensing fiber ring, a photoelectric detector and a signal processing unit. The non-reciprocal magneto-optic modulation avoids the using of a large quantity of polarization-maintaining delay lines, and modulation speed can be decreased at the same time. Due to the using of the round polarization-maintaining transmission optical cable, the polarization state of light is well controlled, and alignment of a polarization main shaft is not needed during welding. According to the interference type fiber optic current sensor based on the magneto-optic modulation, technical difficulty of an active modulation scheme of the interference type fiber optic current sensor can be greatly reduced.

Description

technical field [0001] The invention relates to a novel optical fiber current sensor, in particular, an interference type optical fiber current sensor based on magneto-optical modulation. Background technique [0002] The current sensor is an important device for electric energy measurement and relay protection in the power system. With the development of the electric power industry, the voltage operation level is getting higher and higher, and the traditional electromagnetic current transformer has encountered great difficulties in insulation. The current transformer made of optical fiber has natural advantages in insulation, and also has the advantages of anti-electromagnetic interference, wide measurement frequency range, and digital output. It is the development trend of current sensors in the future. [0003] The basic principle of fiber optic current sensing is the Faraday magneto-optical effect, that is, when an external magnetic field is applied, the polarization dir...

Claims

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Application Information

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IPC IPC(8): G01R19/00G01R15/24
Inventor 肖悦娱
Owner SHANGHAI UNIV
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