Experimental investigation of wavelength and temperature dependence of phase and group birefringence in photonic crystal fibers

Small-core photonic crystal fibers are often strongly birefringent, and consequently lend themselves to polarization maintaining applications or to polarimetric fiber sensors. For both types of use, it is important to have detailed knowledge not only of the fiber´s polarization characteristics, but also of its sensitivity to changes in environmental conditions. For the first time, experimental results of the dependence of phase and group delay on temperature are shown for the important 1500-1600 nm wavelength range. Both the polarization characteristics and its temperature dependence are found to be qualitatively different in a photonic crystal fiber compared to a standard PANDA fiber.