Fano lines in the reflection spectrum of directly coupled systems of waveguides and cavities: Measurements, modeling, and manipulation of the Fano asymmetry

Abstract

We measure and analyze reflection spectra of directly coupled systems of waveguides and cavities. The observed Fano lines offer insight in the reflection and coupling processes. Very different from side-coupled systems, the observed Fano line shape is not caused by the termini of the waveguide, but the coupling process between the measurement device fiber and the waveguide. Our experimental results and analytical model show that the Fano parameter that describes the Fano line shape is very sensitive to the coupling condition. A movement of the fiber well below the Rayleigh range can lead to a drastic change of the Fano line shape.

Adaptive Control of Necklace States in a Photonic Crystal Waveguide

“…From the spectrum in Fig. 3(a) we see that the line shape of mode m 0 resembles a Fano profile, which arises from the interference of the discrete (localized) resonance with a transmission continuum [13][14][15][16][17][18] , see Supplementary Fig. ??.…”

“…From the fact that these modes are discrete (no overlap in frequency unless we tune) and that their mode profile is measured to be smaller than the system size spatially, we conclude they are localized through coherent random scattering, i.e, Anderson localized. From the spectrum in Figure 3 (a) we see that the line shape of mode m 0 resembles a Fano profile, which arises from the interference of the discrete (localized) resonance with a transmission continuum; 17 − 20 see Supplementary Figure S4 . Next, we position the pump beam at position 0, to spatially overlap with m 0 , and tune the refractive index locally.…”

“…The pump–tickle–probe method that we introduce here provide us the means to identify the coupling type, trace the anticrossing regime, and detect spatial mode profile changes of a collection of disordered high- Q localized modes and extended necklace states. Multiple-resonant systems 20 , 22 that we are able to control here are pronounced platforms to study fundamental physics 24 and explore all-optical devices that involve slow light. 25 In more complex geometries, controlling multiple localized modes in a necklace state via holographic patterns can enable routing light on chip in 2D optical networks by coherently coupling Anderson localized modes.…”

Tuning out disorder-induced localization in nanophotonic cavity arrays

“…These fringes results from interference in the system and are addressed in detail in Ref. 24. To extract resonance wavelengths and widths the reflection spectra were fitted with appropriate Fano line-shape of the resonances 25 , as it is shown in Fig.…”

Μη Γραμμικές Νανοφωτονικές Διατάξεις Συντονισμού Της Πλασμονικής Και Του Γραφενίου

“…Η ανάλυση που παρουσιάσαμε αφορά σε έναν συντονιστή στασίμου κύματος πλάγια συζευγμένο με έναν υποκείμενο κυματοδηγό, στον οποίο έχει εγγραφεί ο Fabry-Perot συντονιστής. Η σύνθεση αυτή είναι η πιο συνηθισμένη ολοκληρωμένη διάταξη συντονισμού με απόκριση τύπου Fano και χρησιμοποιείται ευρέως [235][236][237][238]. Στα Σχ.…”