Highly sensitive silicon microring sensor with sharp asymmetrical resonance

Abstract

We analyze the resonance spectrum in silicon microring resonators taking into account the end-facet reflection from a coupled waveguide, which can provide a dense set of Fabry-Perot resonances. Based on the simple configuration of a microring coupled with a waveguide, the resulting asymmetric Fano-like non-Lorentzian resonance is obtained by scattering theory and experiment. Enhanced sensing performance with steeper slope to the resonance is theoretically predicted and experimentally demonstrated for a 10-microm racetrack silicon microring resonator. A high sensitivity of approximately 10(-8) RIU in terms of the detection limit is obtained in a 30-dB signal-to-noise ratio (SNR) system.

Plasmonic external cavity laser refractometric sensor

“…As a result, several types of high-Q dielectric resonators achieve detection figure of merit (FOM) metrics that far exceed that of SPR, where the FOM is defined as FOM = S b /Γ, in order to simultaneously capture the effects of the magnitude of the refractive index induced resonant shift and the ability to measure small wavelength shifts. Alternative passive optical resonator approaches that report FOM values greater than SPR include photonic crystals [14], liquid-core optical fibers [15], whisperinggallery mode microspheres [16], and microring resonators [17]. Because increased Q for an optical resonator has generally also resulted in reduced S b [18], there has been a great deal of research focused on development of active optical resonators that achieve narrow resonant linewidth without sacrificing sensitivity through the process of stimulated emission [18][19][20][21].…”

Novel optical sensor based on the silicon crossing-coupled microring resonator

“…The reason is that the dominant resonance occurs inside the microring cavity, which is superimposed with the Fabry--Perot resonance from the straight waveguide. Therefore, the resulting resonance spectrum shape reflects a multi-resonance-coupling inside the CMR [6]. Fig.3, which indicate a sensitivity as high as 225nm/RIU.…”

Chemical Sensors Based on Photonic Structures

“…The improvement in terms of sensor performance is obtained because in Fano resonance the slope of the line-shape is greater than that obtained with Lorentzian resonance. To this purpose, a highly sensitive silicon micro-ring sensor with sharp asymmetrical resonance has been presented in literature (Yi et al, 2010). Coupled waveguides and micro-ring resonator have been fabricated using a SOI wafer which has a 1 m buffered oxide layer topped with 230nm of Si.…”