Tunable Narrow-Band Filter Based on Long-Range Surface Plasmon Polariton Waveguide Bragg Grating

A narrow-band Bragg grating filter based on a long-range surface plasmon polariton (LRSPP) waveguide is theoretically demonstrated. The three-dimensional Au stripe that is embedded in polymer SU-8 acts as both the waveguide and the heating electrode. With the eigen mode expansion and finite element method optimizations, the proposed filter shows a reflectivity of 0.578 and a 3 dB bandwidth of 1.1 nm. The central wavelength can be tuned from 1549.9 nm to 1544.3 nm by varying temperature from 25 degrees C to 75 degrees C, while maintaining the optical return loss at -2.5 dB. This proposed tunable filter has potential in on-chip light signal processing.

Automated summary

This article theoretically demonstrates a narrow-band Bragg grating filter based on a long-range surface plasmon polariton waveguide, which can achieve a change in the central wavelength through temperature adjustment.