Font Size: a A A

Design And Theoretical Analysis Of Fiber-optic Current Sensorwith Twisted High-birefringence Fibers

Posted on:2015-03-16Degree:MasterType:Thesis
Country:ChinaCandidate:M H KangFull Text:PDF
GTID:2298330452954324Subject:Optics
Abstract/Summary:PDF Full Text Request
Fiber-optic current sensors are vital component in current measurement field, which canrealize high accuracy current measurement with a wide range in hostile environment. Thephase interferometer fiber-optic current sensor is one of widely used fiber-optic currentsensor, which is based on the Faraday effect in optical fibers. The optical fibers are usedfor sensing the Faraday effect and also transmitting light signal. However, in thetraditional phase interferometer fiber-optic current sensor, there still exist some problems.These include the residual linear birefringence of sensing fibers, vibration, temperaturefluctuation, imperfection of fiber quarter-wave plate and its temperature performance,which impact the measurement accuracy.Researchers have been proposed that uniformly twisted high-birefringence fibercould provide high circular birefringence, as nonuniformly twisted high-birefringencefiber could transform polarization of light. Based on the above ideas, we proposed designproposals of novel interferometer fiber-optic current sensors. The design proposalscombined both of the twisted high-birefringence fibers and the fibers were wound intospecial geometric structures. The uniformly twisted high-birefringence fibers are used asthe sensing fiber, sensing and maintain the Faraday effect, since the linear birefringencecan be eliminated in these fibers. Meanwhile, the nonuniformly twistedhigh-birefringence fiber replace the fiber quarter-wave plates, converting the lightpolarization state from linear to circular and vice versa. Thus, the imperfection of thefiber quarter-wave plate, especially with its temperature-dependent phase retardation, canbe eliminated inherently. The fibers are manufactured in high temperature and woundinto special fiber coils, which are immune to vibration and temperature fluctuation. Thusthe sensing fiber coils can adapt to bad weather changes and has good stability.This paper introduces the basic principle of fiber-optic current sensor, and the vitaltechnical problem in traditional phase interferometer fiber-optic current sensor. Thenthree design proposals of novel interferometer fiber-optic current sensors are proposed. Inthese design proposals, the evolutions of polarization are analyzed and the theoreticalmodels are established by Jones matrix respectively. It is the theoretical base formanufacture experimentalprototype in the future.
Keywords/Search Tags:fiber-optic current sensor, Faraday effect, polarization, Jones matrix
PDF Full Text Request
Related items