Research On Sensing With High Birefringent Photonic Crystal Fiber

Since photonic crystal fiber was proposed by P. St. J .Russell in 1992, it has attracted more andmore research interests because of its unique properties such as endless single-mode guiding,chromatic dispersion management, high nonlinearity and high birefringence, etc. High birefringencecan be achieved with its structures designed flexibly. In recent years, research on birefringentproperties and applications of photonic crystal fiber has become a hotspot.A novel side-hole photonic crystal fiber is proposed in this paper. The stress distribution withinthe proposed fiber and the effective refractive indexes of fundamental modes are calculated usingthe full-vector finite element method. In combination with Matlab to do post-processing of data, thebirefringent properties under free load, hydrostatic pressure load and transversal force load with therelationship between structural parameters and the free space wavelength are obtained respectively.The numerical results show that the larger the side hole is and the closer the side hole is tothe core, the higher sensitivities to hydrostatic pressure and transversal load can be achieved; Withinthe measuring range, the shorter the free space wavelength is, the higher the polarimetric phasesensitivities to hydrostatic pressure and transversal load are obtained; The effect of the temperatureon the pressure sensing could be neglected because the polarimetric phase sensitivity to temperatureis small. Under the optimized geometric structure, the initial phase modal birefringence30 B = 2.931×10? , the polarimetric phase sensitivity to hydrostatic pressureK 99.072rad /(MPa m) P = ?×and the polarimetric phase sensitivity to transversal loadK 177.96rad /(N /cm m) f =×(side holes placed from top to bottom),K 177.55rad /(N /cm m) f = ?×(side holes placed from left to right) are achieved at 1.55μm .Finally, the sensing detection system based on the principle of polarization interference isintroduced. The sensing capability of the proposed fiber to hydrostatic pressure and transversalforce is so high that it is believed to be an excellent candidate for pressure sensor.