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 1100°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 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 FFT with different accuracy. This method is especially designed for the long-fluorescence-lifetime system, for example, Erbium-doped fiber sensing with lifetime up to
10mn. 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 the base offset etc.
The effect of this method is discussed and compared with other estimation methods by numerical simulation and experiment results.