Modal coupling in fiber tapers decorated with metallic surface gratings.
An interference-based scheme for fabricating periodic metal gratings on one side of the uniform waist of optical fiber tapers has been developed. Optical characterization of a 5 mm long, 511 nm period gold grating fiber taper with a 10 microm diameter reveals backward coupling to both guided and radiation modes that is explained by using an analytical mode-coupling analysis. A refractometer based on this grating taper has a high and constant sensitivity over a large refractive index operating range of 1 to 1.41.
Ding
W
W
Department of Physics, University of Bath, Claverton Down, Bath, UK. pypwd@bath.ac.uk
Andrews
S R
SR
Birks
T A
TA
Maier
S A
SA