Abstract
A coherence multiplexing scheme for distributed sensors based on fiber Bragg grating (FBG) pairs is
introduced. Each pair of identical FBGs forms a Fabry–Pérot (FP) interferometer (FPI) and induces an
additional optical path difference (OPD) that is proportional to the center-to-center interval between the two FBGs
(one for sensing and the other for reference). The interference intensity reaches its maximum when the FPI-induced
OPD is compensated by scanning one arm of a Michelson interferometer to a certain position. The variation of the
measurand induces a mismatch between the central reflection wavelengths of two FBGs and consequently reduces
interference intensity. To separate the interferometric signals for demultiplexing, the intervals between the two
FBGs are preset to different values for different sensors. In order to improve the multiplexing ability of the
system and reduce the crosstalk among the sensors, we use gratings of low reflectivity. Temperature sensing is
demonstrated to show the high sensitivity (-1.92 %/°C) and low crosstalk of our distributed sensing system.
© 2007 IEEE
PDF Article
More Like This
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription