Design of a high-performance micro integrated surface plasmon resonance sensor based on silicon-on-insulator rib waveguide array

Abstract

Based on silicon-on-insulator (SOI) rib waveguide with large cross-section, a micro integrated surface plasmon resonance (SPR) biochemical sensor platform is proposed. SPR is excited at the deeply etched facet of the bend waveguide by the guiding mode and a bimetallic configuration is employed. With the advantages of SOI rib waveguide and the silicon microfabrication technology, an array of the SPR sensors can be composed to implement wavelength interrogation of the sensors’ output signal, so the spectrometer or other bulky and expensive equipment are not necessary, which enables the SPR sensor to realize the miniaturization and integration of the entire sensing system. The performances of the SPR sensor element are verified by using the two-dimensional finite-different time-domain method. The parameters of the sensor element and the array are optimized for the achievement of high performance for biochemical sensing application. As a typical example, a single bimetallic SPR sensor with 3 nm Au over 32 nm Al possesses a high sensitivity of 3.968 × 10 4 nm/RIU, a detection-accuracy of 14.7 μm -1. For a uniparted SPR sensor, it can achieve a detection limit of 5.04 × 10 -7 RIU. With the relative power measurement accuracy of 0.01 dB, the refractive index variation of 1.14 × 10 -5 RIU can be detected by the SPR sensor array.