New Fiber Grating Sensor Multiplexing System

Fiber gratings are new type of passive optical components, which are based on the periodical distribution of refraction index in fiber core. They are one type of developing fast passive fiber devices in recent years. Fiber gratings have several distinguished advantages, such as compare with fiber, low loss and high responsibility. As sensing element, they encode the sensing information in a wavelength form, which are their distinguished advantages over other transducers. That not only make the sensing information does not depend on loss of the system or fluctuation of then source power but also decrease the cost of sensing system and realize multipoint and distributed sensing. Therefore, lots of researchers are interested in fiber grating sensing multiplex techniques.In this dissertation, we mainly focus on the research and realization of fiber Bragg grating networks, including the principles and experiments of sensing and demodulation techniques. The contents are listed as follows:1. Generally introduce the sensing technique, especially the present situation and development of fiber grating sensing technique and fiber Bragg grating sensor multiplexing technique. The basic principle of PETRI NET theory and queue theory can be found in this dissertation. Then, we analyze the disadvantage of the combination of wavelength- and spatial-division multiplexing technique.2. A novel fiber Bragg grating sensors multiplexing system which combined with HiBi FLM and F-P filter is put forwarded. The experiment and the theory analysis demonstrated that the system only scan and demodulate sensing channels, whose wavelength is shifting. What's more, the smart FBG sensors multiplexing system can rule the demodulate sequence by the priority, the waiting time and the wavelength shifting of every sensing channels. Therefore, the smart FBG sensors multiplexing system is more rational and smarter than the conventional counterpart.3. A novel multiplexing system which combined with InGaAs array and F-P filter is raised, analyze the disadvantage of the FBG multiplex technique which combined...