New method to estimate the fluorescence lifetime of the Erbium-doped-fiber temperature sensing system

Abstract

Erbium doped fiber is a main component of Erbium Doped Fiber Amplifiers (EDFAs), which is wildly used in optical communication. Erbium doped fiber is a good sensing material of fluorescence temperature sensors as well. The Erbium-doped-fiber temperature sensors can operate under high temperature up to 1 100 °C.Fluorescence sensors show considerable promise, with the advantage of being intensity independent. Following the termination of a square excitation light pulse, the fluorescence signal is an exponential decay, which decay lifetime depends on the temperature and can be measured by several methods. The decay acquisition and estimation methods are one kind of them. Different arithmetic is developed such as the Marquardt method, the Prony method and the log-fit method.A new estimation method is given in this paper, basing on the FFT (Fast Fourier Transform) and the Taylor series. The fluorescence lifetime can be calculated from the items of the FF1' with different accuracy. This method is especially designed for the long-fluorescence-lifetime system, for example, Erbium-doped-fiber sensing system with lifetime up to lOms. However this method can be used for other fluorescence material also with a little shift. The advantages of this method include high accuracy, quick processing, independence on base offset etc.The effect of this method is discussed and compared with other estimation methods by numerical simulation and experiment results.