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 μm 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.
© 2006 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: May 17, 2006
Manuscript Accepted: June 14, 2006
Published: August 9, 2006
W. Ding, S. R. Andrews, T. A. Birks, and S. A. Maier, "Modal coupling in fiber tapers decorated with metallic surface gratings," Opt. Lett. 31, 2556-2558 (2006)