Research On Optical Voltage Transducer Based On Modular Interference Of Highly Birefrigent Photonic Crystal Fiber

Photonic Crystal Fiber (PCF) is a new special type of optical fibers. The periodical or random arrangement of micrometer-scale air holes running along the full length of the fiber in the cladding region brings flexibility for the design and fabrication of fiber. Highly birefringence can be obtained by introducing the stress-applying parts into the core or changing the dimension and location of the air holes of PCF. Compared with the conventional polarization maintaining fiber (PMF), highly birefringent PCF (HB-PCF) has many advantages, such as the higher sensitivity, the better temperature stability and the better ability of polarization maintaining, which make it apply to a wide range field related with optical fiber sensing. This paper researches the modular interference characteristics of HB-PCF, and applies HB-PCF to optical voltage transducer (OVT), providing a novel thought to optical voltage and current transducer.This paper introduces the principles and the applications in HB-PCF sensing. Referring to the development status, basic theory of OVT in the world, the modular characteristics of HB-PCF is analyzed, and an OVT based on HB-PCF is proposed and studied theoretically and experimentally. The main contents are as follows:First, the mode properties of two-hole PCF, near-rectangle PCF and hexagonal core PCF are analyzed using finite-element method in order to find the proper HB-PCF used for OVT. The dependence of modal birefringence on the wavelength, the cut-off wavelength of guided modes and the wavelength range for two-mode operation are researched. Taking two-hole PCF as the example, the effects of structural parameters on modal birefringence and mode field radius are discussed.Second, the modular interference characteristics of elliptical core PMF, two-hole PCF and near-rectangle PCF are simulated. The cut-off wavelength of guided modes, the dependence of the modular interference sensitivity and mode field properties on wavelength are compared. The results show that HB-PCF is more suitable for OVT.Third, the effects of structural parameters on modular interference in two-hole PCF are discussed. The wavelength range for two-mode operation, the relationship between the modular interference sensitivity and wavelength in two-hole fiber with different structure parameters are analyzed. The optimal structure of two-hole PCF for modular interference is designed.Fourth, the experimental system of PCF OVT based on modular interference is set up. The phenomena of modular interference about two-hole PCF are observed. The modular interference sensitivity of two-hole PCF is measured when the fiber's length is changed by tensing or using the converse piezoelectric effect of PZT. The low voltage sensor system based on PZT and the high voltage sensor system based on quartz crystal are researched experimentally. The results are analyzed and discussed.