Title :
Bragg grating evanescent field sensor made in biconical tapered fiber with femtosecond IR radiation
Author :
Grobnic, Dan ; Mihailov, Stephen J. ; Ding, Huimin ; Smelser, Christopher W.
Author_Institution :
Commun. Res. Centre Canada, Ottawa, Ont., Canada
Abstract :
Retro-reflective Bragg gratings were made with a phase mask and femtosecond radiation from a Ti : sapphire infrared laser into the core and cladding region of a tapered single-mode fiber. The evanescent field in the taper interacts with the ambient environment and the intensity of the reflected signal is used to measure the refractive index changes of the ambient environment as low as 2.5×10-5. By controlling the immersion depth of the grating taper, use of the taper as a single port point sensor for measuring fluid levels is also demonstrated.
Keywords :
Bragg gratings; fibre optic sensors; high-speed optical techniques; laser beam effects; level measurement; optical fibre cladding; reflectivity; refractive index measurement; Al2O3:Ti; Bragg grating sensor; IR radiation; Ti:sapphire laser; ambient environment; biconical fiber; evanescent field; evanescent field sensor; femtosecond radiation; fluid level measurement; grating taper,; immersion depth; infrared laser; phase mask; reflected signal intensity; refractive index changes; retroreflective Bragg gratings; single port point sensor; single-mode fiber; tapered fiber; Bragg gratings; Fiber gratings; Infrared sensors; Optical fiber communication; Optical fiber couplers; Optical fiber devices; Optical fiber sensors; Optical fibers; Refractive index; Ultrafast optics; Evanescent field; fiber Bragg gratings (FBGs); fiber sensors; fiber tapers; ultrafast optics;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2005.860372
