Bragg gratings based on long-range surface plasmon-polariton waveguides: comparison of theory and experiment

Measured optical spectra are presented for a family of third-order uniform step-in-width Bragg gratings operating in the long-range surface plasmon-polariton mode supported by thin finite-width Au films in a homogeneous dielectric background. The spectra are compared quantitatively with theoretical predictions generated by a model proposed for the gratings. Physical measurements of critical features achieved on-wafer have been made and the results used in the theoretical model. The measured and modeled results are generally in good agreement. The largest reflectance measured among the set of gratings characterized is 47.4%, the bandwidths (full width at half maximum) measured range from 0.2 to 0.4 nm, and the measured Bragg wavelengths coincide to 1544.2 nm for all of the gratings.