A Study on the Fabrication of Polarimetric Fiber Optic Current Sensor

편광측정법에 의한 광섬유 전류 센서 제작에 관한 연구

  • Jang, Nam-Young (Changwon National University, Dept. of Electronic Engineering) ;
  • Chio, Pyung-Suk (Changwon National University, Dept. of Electronic Engineering) ;
  • Eun, Jae-Jeong (Changwon National University, Dept. of Electronic Engineering) ;
  • Park, Hae-Soo (Korea Electrotechnology Research Institute)
  • Published : 2004.06.30

Abstract

In this paper, a polarimetric fiber optic current sensor(P-FOCS) is experimented and fabricated, and then a possibility to the commercial utilization of the P-FOCS is also investigated. The P-FOCS measures an applied current by a Faraday rotation linearly proportional to a magnetic field generated by the applied current. The bending-induced linear birefringence in the sensing fiber is minimized by using the low birefringent fiber. Also, all fiber-optic components are used to avoid optical losses coming from the use of bulk components. A signal processing circuit is constructed and used to eliminate the effects of intensity variations in the output signal due to losses coming from misalignments of components such as fiber connectors. Using the optical source of 632.8nm wavelength, Faraday rotation is measured by passing through the sensing fiber within the solenoid of about 1500 turns which is equivalent to a current source of about 7500A. In the range of 1000A to 7500A, the measurement error for linearity is within about 1.5%.

본 논문에서는, 편광측정법에 의한 광섬유 전류 센서(P-FOCS)를 실험·제작하여, 실제 필드에 적용할 수 있는 P-FOCS의 상용화 가능성에 대하여 연구하였다. P-FOCS는 인가된 전류에 의해 발생한 자기장에 비례하는 Faraday 회전각을 측정함으로서 인가된 전류를 측정한다. P-FOCS의 센싱 광섬유로는 저복굴절 광섬유를 사용하여 밴딩에 의한 선복굴절의 영향을 최소화하였으며, 벌크(bulk)한 광학소자의 사용으로 인한 광 손실을 막기 위해 전 광섬유 소자를 사용하였다. 또한, 구성된 신호처리회로는 광섬유 소자들의 연결부에서의 손실로 인한 출력 신호의 강도 변화를 제거하기 위해 사용된다. Faraday 회전각은, 632.8nm 파장의 광원을 이용하여 권선수가 약 1500인 솔레노이드에 전류를 인가해 7500A의 전류원의 효과를 얻도록 하여, 솔레노이드 내부에 센싱 광섬유를 통과시켜 측정하였다. $1000A{\sim}7500A$ 범위에서, 선형성의 측정 오차는 약 1.5% 이내였다.

Keywords

References

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