Fbg Sensing Network Based On The Novel Demodulation Scheme

Fiber grating is one of the most rapidly developed and most widely used passive devices in recent years. Fiber gratings can be used to measure temperature, strain, pressure, electromagnetic fields, and some other parameters. As sensing components, FBG not only inherited the ordinary fiber sensors' small size, large bandwidth, anti-electromagnetic interference ability, anti-high temperature and corrosion, and other advantages, but also has its own unique advantages, such as wavelength sensing signal coding, Easy to integrate, easy to form distributed sensor array, using multiplexing and network technologies developed in optical communication area, FBGs can be easily multiplexed as a variety of forms of FBG sensor network.In this paper, we mainly studied the fiber Bragg gratings. The FBG sensor technology, packaging technology and multiplexing technology were discussed. The main work and results in this paper are following:1. The development of FBG sensor technology and applications were briefly introduced. Theoretical models of fiber Bragg grating and basic principles of FBG strain and temperature sensor were introduced.2. Some common packaging technologies for FBG sensors were discussed. A temperature sensor design was proposed. A novel methane concentration sensor based on FBG was proposed. Design and packaging technology for FBG methane concentration sensor were described in detail, and a new detection system with high sensitivity (0.783V/1%) and high resolution (0.0064%) was proposed for methane concentration sensor.3. Some common demodulation methods and multiplexing methods were discussed. A coherence multiplexing technology based on fiber Bragg grating pairs was proposed, a high temperature sensitivity (-1.61%/℃) was achieved.4. A hybrid multiplexing system based on spatial division multiplexing and coherence multiplexing was proposed. With this low cost system, a high multiplexing ability and high sensitivity can be achieved. The gratings used in this system can be fabricated with one phase mask under the same parameters.