SINGLE-MODE OPTICAL FIBER SENSORS

A review of the range of types and applications of optical fiber sensors, with the emphasis on single-mode fiber sensors, is presented. Two sensors are dealt with in more detail. The first is a dual-mode fiber sensor. Results of experiments designed to assess the thermal sensing characteristics of this sensor, used in both phase and wavelength modulating regimes, are presented. In the phase modulating regime the sensitivity is more than two orders of magnitude less than that of the best interferometric sensors. The advantages of operating in the wavelength modulating regime are outlined, and the feasibility of operating the dual-mode sensor in this manner is demonstrated. It is suggested that an interesting application of this sensor would be hydrophones, since it would be capable of absolute as well as dynamic pressure measurement. The second sensor is a distributed sensor using optical time domain reflectrometry, the attractive features of which are outlined. Feasibility is experimentally demonstrated.