800 nm WDM Interrogation System for Strain, Temperature, and Refractive Index Sensing Based on Tilted Fiber Bragg Grating

A low-cost high-resolution wavelength-division-multiplexing (WDM) interrogation system operating around 800 nm region with operational bandwidth up to 60 nm and resolution of 12.7 pm utilizing a tilted fiber Bragg grating (TFBG) and a CCD-array detector has been implemented. The system has been evaluated for interrogating fiber Bragg grating based strain, temperature sensors, giving sensitivities of 0.59 pm/muepsiv and 5.6 pm/degC, which are in good agreement with previously reported values. Furthermore, the system has been utilized to detect the refractive index change of sample liquids, demonstrating a capability of measuring index change as small as 10-5. In addition, the vectorial expression of phase match condition and fabrication of TFBG have been discussed.