One of the most significant limitations of FBG sensors is their dual sensitivity to temperature and strain. Many
methods have reported to avoid this problem by using a tapered fiber grating for the strain measurement free from
temperature influence. But all of them are based on the measurement of the reflected power from the tapered fiber
grating (TFG). In fact, they have abandoned the major advantage that the measured information is encoded in light
wavelength instead of light intensity of FBG sensors, and the revolution of these sensors is begin to depend on the light
power fluctuation, connection loss and many other elements. All of these would enlarge the cost of the sensing system.
On the basis of the theory calculation and experiment, we demonstrate the feasibility to make a temperature-independent
strain sensor by measuring the bandwidth of the reflected light from the tapered fiber grating. In this paper, we also
present a novel demodulating method based on a scanning FBG. In the experiment, a PZT is used to make the reflected
wavelength of FBG scanned from short wavelength to long wavelength to measure the bandwidth of the reflected light
from TFG. From the experimental results, it could be seen that the influences of the light power fluctuation and
connection loss are eliminated thoroughly. This simple and low-cost sensor approach has a considerable potential,
particularly application for strain sensing in the smart structures.