Polarimetric optical fiber sensors based on highly birefringent (HB) polarization-maintaining fibers have focused great interest for last decades. The paper presents a novel modular fiber optic sensing system of potential industrial applications to measure temperature, hydrostatic pressure, and strain that is based on classical HB and photonic crystal fibers and can operate at visible and infrared wavelengths. The main idea of the system is a novel and replaceable fiber-optic head, which allows adjusting the measuring system both to the required range and type (strain, pressure or temperature) of the external measurand. We propose also a new configuration of the fiber optic strain gauge with a free cylinder and an all-fiber built-in analyzer based on the photonic crystal fiber filled with a liquid crystal. Additionally, strain sensitivities of various HB fibers operating at visible and infrared wavelengths range have been measured.
PCFs (Photonic Crystal Fibers) with ‘T’ – shaped core have been proposed in this paper. ‘T’ –shaped core PCF structures have been analyzed using two different background materials: silica and lead silicate. A total of 3600 rotation at an interval of 900 has been introduced in the design of PCF structures. PCF structures A, B, C and D with rotation of 00, 900, 1800 and 2700 have silica as wafer. Similarly PCF structures E, F, G and H with similar rotation have lead silicate as background material. Numerical investigations shows structures ‘D’, ‘F’, ‘G’ and ‘H’ to have anomalous dispersion. PCF structures ‘F’, ‘G’, and ‘H’ have reported birefringence of the order of 10-2. Besides, other PCF structures report birefringence of the order of 10-3. Ultra low confinement loss has been observed in all the investigated PCF structures. Moreover, splice loss observed by the structure is very low. Large mode area has been shown by all the designed PCF structures.