Tunable dynamic Fano resonances in coupled-resonator optical waveguides

Abstract

A route toward lineshape engineering of Fano resonances in photonic structures is theoretically proposed, which uses dynamic modulation of the refractive index of a microcavity. The method is exemplified by considering coupled-resonator optical waveguide systems. An exact Floquet analysis, based on coupled-mode theory, is presented. Two distinct kinds of resonances can be dynamically created, depending on whether the static structure sustains a localized mode or not. In the former case a single Fano resonance arises, which can be tuned in both frequency and line width by varying the refractive index modulation amplitude and frequency. In the latter case two resonances, in the form of narrow asymmetric dips in the transmittance, are found, which can overlap resulting in an electromagnetically-induced transparency effect.

Optical multistability and Fano line-shape control via mode coupling in whispering-gallery-mode microresonator optomechanics

“…He discovered that the shape of this resonance, which is based on the interaction of a discrete excited state of an atom with a continuum of scattering states, is quite different from the resonance which generally described by the Lorentzian formula. Because of the asymmetry of the Fano line-shape and the enhanced interference effect, many theoretical47484950515253 and experimental545556575859 works have be done so far.…”

Silicon ring resonator-coupled Mach–Zehnder interferometers for the Fano resonance in the mid-IR

“…T plitter and an outp 9]. In addition, th oupler, g, as well a e MZI i.e., ∆ 2 ⁄ , h The design and is paper have bee o far [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] performing an optimal design of the waveguide structures in order to minimize the optical confinement of the fundamental mode in the buried silicon dioxide (SiO2). Moreover, state-of-the-art processing facilities and optimized recipes facilitated the fabrication of highquality devices with low loss.…”

“…In particular, Fano resonances result from the interference between a resonance pathway and a coherent background pathway. Moreover, they can be varied by tuning the relative phase between the resonances and coherent background pathways, and are ubiquitous in a large number of optical resonant configurations and nanophotonics devices [15][16][17], including, for example, integrated nested ring resonator, standard ring resonator and multiple ring resonators loaded on an MZI arms, as well as exotic photonic integrated architectures [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Finally, it has been demonstrated that RR-coupled MZI devices can exhibit a 30.5% enhancement in sensitivity over conventional ring resonators [22], making them suitable for photonic sensing and filtering.…”

Controllable optical bistability and Fano line shape in a hybrid optomechanical system assisted by kerr medium: possibility of all optical switching

“…Fano resonance is different from electromagnetically induced transparency (EIT) and OMIT, both of which have symmetric line profile. The asymmetry of the Fano line shape and enhanced interference effect has attracted many theoretical [44][45][46][47] as well as experimental investigations [48][49][50][51].…”