Full optical fiber current sensor

Abstract

The invention discloses an all-fiber current sensor consists of a 3x3 polarization-maintaining fiber coupler. One embodiment of the invention, a straight-through type interferometric all-fiber current sensor, comprises a light source, a 3x3 polarization-maintaining fiber coupler, fiber polarizers, a 1/4 fiber wave sheet and a transduction fiber ring. The light source is connected with one end of the 3x3 polarization-maintaining fiber coupler; the two ports of the 3x3 polarization-maintaining fiber coupler are respectively connected with two fiber polarizers; and the other ends of the two fiber polarizers are respectively connected with the transduction fiber ring by the 1/4 fiber wave sheet; one port of the 3x3 polarization-maintaining fiber coupler is vacant; and the rest two ports of the 3x3 polarization-maintaining fiber coupler are respectively connected with a signal processor by two photoelectric detectors. In addition, another embodiment of the invention, a reflection type interferometric all-fiber current sensor, also uses the 3x3 polarization-maintaining fiber coupler. The all-fiber current sensor avoids phase differences made artificially and makes the current transduction system woke more stably.

Description

technical field [0001] The invention relates to an all-fiber current sensor, in particular to an all-fiber current sensor composed of 3x3 polarization-maintaining fiber couplers. Background technique [0002] At present, the measurement of AC large current generally adopts the current transformer method. Under the ultra-high voltage state, due to the difficulty of insulation, the ultra-high voltage current transformer is complicated to manufacture, so the price is very expensive. The quartz material used to make optical fibers is itself a very good insulator. Using optical fiber current sensors made of optical fibers to measure current can theoretically measure all currents under high-voltage conditions. Therefore, it is generally considered that the fiber optic current sensor is an ideal substitute for the high voltage current transformer. [0003] The optical fiber current sensor uses the Faraday effect of light, that is, an optical fiber with an appropriate number of tur...

AI Technical Summary

Problems solved by technology

[0006] In view of the above shortcomings of the current sensor composed of 2x2 fiber optic couplers, the industry tries to use 3x3 fiber optic couplers to form a Sagnac optical circuit to solve the problem of phase bias. The optical fiber has no ability to maintain polarization, so the Sagnac interference optical path composed of a 3x3 fiber coupler prepared by a conventional optical fiber is unstable and has no practical value

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