Fiber-loop Ring-down Spectroscopy For Pressure And Strain Measurement

Fiber-loop ring-down spectroscopy (FLRDS) is a very high sensitive absorptionspectroscopy technique, combining cavity ring-down spectroscopy (CRDS) with opticalfiber sensing technique, allowing for a broad range of new applications, including themeasurement of optical loss, pressure, strain, concentration of liquid sample. Optical fibersensing technique has developed with optical fiber communication technique, it has beenproceed to be superior to the conventional electrical-based sensors in many respects. Thedevelopment of fiber pressure and strain sensors have progressed rapidly since 1970s, andthe sensors benefit a wide range of industries, including the aerospace, military, oil,biomedical and structural sectors. Currently, the most popular fiber pressure and strainsensors are based mainly on fiber Fabry-Perot interference or fiber Bragg gratings, but thefirst one can not reach the high pressure limit in some applications, the latter one iscomplicated and expensive. In this thesis we explore optical sensors based on FLRDS forpressure and strain measurement, the results demonstrate the sensing system has highsensitivity, rapid linear response, large dynamic range, good repeatability and low cost.