Spectral characteristics of tapered LPG device as a sensing element for refractive index and temperature

The fabrication and characterization of long-period gratings (LPGs) in fiber tapers is presented alongside supporting theory. The devices possess a high sensitivity to the index of aqueous solutions due to an observed spectral bifurcation effect, yielding a limiting index resolution of /spl plusmn/8.5/spl times/10/sup -5/ for solutions with an index in the range 1.330-1.335.