Temperature sensitivity of photonic crystal holey fibers

Applying an effective index method, we determined the dependence of propagation constants upon temperature in photonic crystals holey fibers with hexagonal and elliptical cores. Our analysis shows that modal birefringence increases with temperature and wavelength in photonic crystal fibers with elliptical core, which is an effect, opposite. to that observed in classical elliptical-core fibers. Some of the calculations were carried out for the fibers recently manufactured at Laboratory of Optical Fiber Technology, MCS University in Lublin, Poland.