A Narrowband Metal–Multi-Insulator–Metal Waveguide Plasmonic Bragg Grating

A narrowband waveguide plasmonic Bragg grating based on metal-multi-insulator-metal configuration is proposed and investigated. The general dispersion relation in the vicinity of each forbidden band is derived from which the operation and design principles are developed. Narrowband design examples with the grating length of ¿6.8 ¿m and the full-width at half-maximum bandwidth of approximately 9 nm in the 1310-nm band are numerically demonstrated. Time-average power flow vortexes are found in each unit cell in the forbidden band and are least-coupled with each other at the Bragg wavelength.