800nm fiber Bragg Grating sensing interrogation system using TFBG and CCD array

An 800nm band fiber Bragg grating sensing interrogation system using TFBG as the core wavelength division component is presented. A charge coupled device (CCD) linear array is put on the focal plane of the lens to detect the light. TFBG is used to tap light out of the fiber core to fiber cladding. The sensing wavelength is 795 to 830nm, with accuracy of 20pm and scan speed 100Hz. Using FBG sensor, we achieve the temperature sensitivity as 1.8°C and strain sensitivity as 18με

Study on vibrating demodulation with fiber Bragg grating sensor

Being used as sensors of vibration is one the most important uses of fiber Bragg grating (FBG). Firstly, the normal principle of the sensors with FBG is introduced. Then we summarize five kinds of demodulation of vibration with FBG that are commonly used. The principle and scheme of the experiment are given respectively, and their character and function (especially the measurement accuracy) are analyzed. This paper provides foundation for the design of the demodulation of vibration with FBG

Design of tunable bandgap guidance in high-index filled microstructure fibers

Tunable photonic bandgap (PBG) microstructure fibers, which were filled nematic liquid crystals (NLC), were theoretically investigated based on bandgap theory. By means of the modified plane-wave method, it is found that PBGs shift to the longer wavelength with increasing refractive index of NLC [ny(?)] for y-polarized light. Fundamental modes are found in these PBG reigns, whose effective mode area, leakage loss and group velocity dispersion (GVD) have been calculated by using the full-vector finite-element method with anisotropic perfectly matched layers. The mode fields become larger with the increase of ny(?) , whereas the leakage loss varies slightly. Moreover, GVD is strongly dependent on ny(?) and wavelength, which is much larger than the material dispersion of silica

Transformation of a transmission mechanism by filling the holes of normal silica-guiding microstructure fibers with nematic liquid crystal

Transformation of an optical transmission mechanism was achieved when the holes of normal silica-guiding microstructure fiber (MF) were filled with nematic liquid crystal (NLC). Moreover, two photonic bandgaps (PBGs) were obtained by using a plane-wave method to create the pattern. The wavelength dependence of the effective mode area, leakage loss, and group velocity dispersion (GVD) has been theoretically investigated by using a full-vector finite-element method with anisotropic perfectly matched layers. The results reveal that the characteristics of the NLC-filled PBG-MFs are particularly wavelength dependent. This research gives a physical insight into the propagation mechanism in MFs and is crucial for future transmission applications