Technological Study On Fiber Fabry Perot Strain Sensor Demodulated By Tunable Fabry Perot

With the development of our society, the infrastructures have been improved greatly. The large constructions have played a very important role in people's lives. Monitoring of these significance structures is fundamental in order to guarantee the safety of themselves and their users. The fiber Fabry Perot strain sensor has charming market prospect with its distinctive property. But the currently prevailed fiber Fabry Perot strain sensor system based on spectrometer is partly restrained in the structural monitoring field because of its relative expensive cost comparing to the traditional monitoring method. At the beginning of this paper the principle of fiber Fabry Perot strain sensor is presented briefly, and the influence brought by the spectrum distribution of light source and light transmitting loss in fiber Fabry Perot cavity. Then the output light's characteristic of two　double-FPI systems are studied respectively, in one system the two FPIs are linked with reflection-reflection mode, and in another systems two FPIs are linked with reflection-transmition mode. According to above theories, two fiber Fabry Perot strain sensor systems based on tunable Fabry Perot are researched deeply. In these two systems the tunable Fabry Perot interferometers act as cross-correlator and filter respectively. Finally one structure of fiber Fabry Perot tunable filter is presented, it has been proved that its cavity length can be controlled by external voltage through experiment. Through analysis it can be said that with the fiber Fabry Perot tunable filter the cost of fiber Fabry Perot strain sensor system is likely to be reduced...