| 摘要 |
Disclosed herein is an optical sensor design and method for continually interrogating that sensor to produce an accurate representation of a dynamic event (such as a change in strain, pressure or temperature) being monitored by the sensor. The sensor design preferably constitutes continuous wave optical source/detection equipment coupled in series to a first fiber Bragg grating (FBG), a long period grating (LPG), and a second FBG formed in an optical waveguide. The LPG broadly attenuates light in the vicinity of the Bragg reflection wavelength lambda2B of the second FBG, and this attenuation profile shifts in wavelength in accordance with the dynamic event being monitored. Perturbation of the attenuation profile thus attenuates the intensity of the light reflected from the second FBG, i.e., I(lambdaB2), because such reflected light must pass (twice) through the LPG. Accordingly, continually monitoring I(lambdaB2) as a function of time allows the dynamic event to be recreated and processed accordingly. If necessary, I(lambdaB2) can be normalized by dividing it by the intensity of the Bragg reflection wavelength from the first FBG, I(lambdaB1), to discard attenuation within the system not related to the dynamic event being monitored.
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