Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7926375 | Optics Communications | 2018 | 6 Pages |
Abstract
Interferometric interrogation technique realized for conventional fiber Bragg grating (FBG) sensors is historically known to offer the highest sensitivity measurements, however, it has not been yet explored for Ï-phase-shifted FBG (ÏFBG) sensors. This, we believe, is due to the complex nature of the reflection/transmission spectrum of a ÏFBG, which cannot be directly used for interferometric interrogation purpose. Therefore, we propose here an innovative as well as simple concept towards this direction, wherein, the transmission spectrum of a ÏFBG sensor is optically filtered using a specially designed fiber grating. The resulting filtered spectrum retains the entire characteristics of a ÏFBG sensor and hence the filtered spectrum can be interrogated with interferometric principles. Furthermore, due to the extremely narrow transmission notch of a ÏFBG sensor, a fiber interferometer can be realized with significantly longer path difference. This leads to substantially enhanced detection limit as compared to sensors based on a regular FBG of similar length. Theoretical analysis demonstrates that high resolution weak dynamic strain measurement down to 4 pεâHz is easily achievable. Preliminary experimental results are also presented as proof-of-concept of the proposed interrogation principle.
Related Topics
Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
Deepa Srivastava, Umesh Tiwari, Bhargab Das,