Phase interrogation of a planar integrated refractive indexsensor

摘要

A novel theoretical scheme is presented for a surface plasmon-polariton (SPP) planar refractive index sensor based on one of the simplest integrated optical devices available, the Mach-Zehnder interferometer (MZI), to monitor relative phase variations in waveguides. An SPP is excited with the Bragg grating imprinted into core and buffer layers of one of the arms of the MZI. The main principle of operation of this device is based on the large phase change of the waveguide mode transmitted through the grating during the SPP excitation caused by the change in the refractive index of the sensed layer in contact with the SPP supporting metal layer.