Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Optics Letters

Tunable Fano and EIT-like resonances based on two cascaded micro-ring resonators

Xudong Zhou, Mingrui Yuan, Shijing Qin, Huifu Xiao, Yongheng Jiang, Jianhong Yang, Thach Giang Nguyen, Guanghui Ren, Arnan Mitchell, Yonghui Tian

Published Mar 24, 2025• 5 citations
Publisher

Abstract

Microring resonators (MRRs) are key building blocks in integrated photonics, but their performances usually suffer from limitations in extinction ratio and slope rate (SR), primarily due to their symmetrical Lorentzian resonance line shape. To overcome these limitations, special transmission spectra (STS), such as Fano resonance and electromagnetically induced transparency (EIT)-like resonance, offer asymmetric line shapes that exhibit a higher extinction ratio (ER) and a steeper SR, thereby enhancing the sensitivity and selectivity of optical switches, filters, and high-sensitivity sensors. However, the current reported works typically achieved only one type of STS and had limited tunability. In this Letter, we experimentally demonstrate a novel, to the best of our knowledge, device using two cascaded MRRs with different quality factors to generate Fano and EIT-like resonances at distinct ports. The ER can reach up to 31.2 dB with a sharp SR of 130.1 dB/ nm, for Fano resonance, and the EIT-like resonance is 12.4 dB. By adjusting the resonator wavelength of the MRRs and the phase shifter, the STS can be working at any desired wavelength. The device is demonstrated on a silicon-on-insulator platform, offering versatile application potential in optical sensors, slow and fast light generation, and microwave photonics.

DOI
10.1364/ol.549345

Related papers

Compact tunable electromagnetically induced transparency and Fano resonance on silicon platform

Shuang Zheng, Zhengsen Ruan, Shengqian Gao +8 more

We propose and demonstrate an on-chip coupling resonant system to generate electromagnetically induced transparency (EIT)-like effect and Fano resonance on silicon platform. It is composed of a microring resonator (MRR) and two cascaded Sagnac-loop mirrors (SLMs) assisted Fabry-Perot (FP) cavity on silicon-on-insulator. According to the coupling conditions of the MRR, two cases are studied theoretically. When the MRR is over coupling, EIT-like transmission can be observed. In contrast, Fano resonances can be generated by the condition of under coupling. In the experiment, the add-drop MRR is under coupling, leading to a sharp asymmetric line shape for Fano resonance. The resonance wavelength of the MRR can be dynamically tuned based on thermal-optic effects by tuning the micro-heater. The experiment results show Fano resonances with maximum extinction ratio (ER) of 23.22 dB and maximum slope rate (SR) of 252 dB/nm. Moreover, the wavelength of Fano resonance can be shifted widely with a tuning efficiency of 0.2335 nm/mW.

Optics Express•Oct 9, 2017•61 citations

The Fano and EIT-like resonance characteristic of asymmetric double micro-ring resonator

Chao Zhao

By breaking the symmetrical arrangement of double micro-ring resonator, the formation mechanism and performance of reflection and transmission spectrum and optical field distribution are investigated. The reflection spectrum is Fano shape. The Fano resonance has an asymmetric and sharp resonance peak can be independently tuned by changing the asymmetric coupling factor of the first micro-ring. The transmission spectrum is electromagnetically induced transparency(EIT)-like shape. The (EIT)-like resonance can be independently tuned by changing the absorption factor and the phase shift factor of the second micro-ring. The Fano and EIT-like resonance have low loss and high near-field localization characteristics, our research has promising applications in optical communication and opto-electronic modulators.

arXiv:2407.20282•Jul 26, 2024•0 citations

Conversion between EIT and Fano spectra in a microring-Bragg grating coupled-resonator system

Zecen Zhang, Geok Ing Ng, Ting Hu +6 more

A conversion between the electromagnetically induced transparency (EIT) transmission and Fano transmission is theoretically and experimentally demonstrated in an all-pass microring-Bragg grating (APMR-BG) coupled-resonator system. In this work, the coupling between the two resonators (the microring resonator and the Fabry-Perot resonator formed by two Bragg gratings) gives rise to the EIT and Fano transmissions. The resonant status strongly depends on the round-trip attenuation of the microring and the coupling strength. By tuning the coupling strength, the EIT and Fano transmissions can be controlled and converted. The device performance has been theoretically calculated and analyzed with a specially developed numerical model based on the transfer matrix method. The APMR-BG coupled-resonator systems with different gap widths were designed, fabricated, and characterized on a silicon-on-insulator (SOI) platform. The conversion of resonance was experimentally observed and verified. In addition, this on-chip system has the advantage of a small footprint, and the fabrication process is compatible with the planar waveguide fabrication process.

Applied Physics Letters•Aug 21, 2017•38 citations

Tunable Fano and EIT-Like Resonances in a Nested Feedback Ring Resonator

Kai Ma, Yundong Zhang, Huaiyin Su +3 more

In this paper, we realize tunable Fano and electromagnetically induced transparency (EIT)-like resonances in the outputs of a nested feedback ring resonator. Compared with the traditional add-drop ring resonator, the feedback arm introduces interference between different resonance modes. Using coupled mode theory, we reveal that the output Fano resonances are the interference of discrete modes and continuum modes, whereas the EIT-like resonance only appears in the over-coupled state. We experimentally confirm the two effects using optical fiber ring resonators, finding that the Fano effect can be easily controlled with phase shifts in the feedback arm. Moreover, we achieve the double Fano resonance, which displays an ‘X’ type lineshape utilizing one ring resonator, predicting it to be a good candidate in wavelength monitor. The proposed simple configuration provides a platform to study Fano and EIT-like effect, which is useful in the optical filter, fast and slow light, optical switching, and optical sensing.

Journal of Lightwave Technology•Apr 2, 2021•15 citations

Electromagnetically induced transparency-like effect in microring-Bragg gratings based coupling resonant system

Zecen Zhang, Geok Ing Ng, Ting Hu +5 more

An all-pass microring-Bragg gratings (APMR-BG) based coupling resonant system is proposed and experimentally demonstrated to generate electromagnetically induced transparency (EIT)-like transmission for the first time. The coupling between two light path ways in the micro-ring resonator and the Fabry-Pérot (F-P) resonator formed by two sections of Bragg gratings gives rise to the EIT-like spectrum. This system has the advantage of a small footprint consisting of only one microring resonator and one bus waveguide with Bragg gratings. It also has a large fabrication tolerance as the overlap requirement between the resonance wavelengths of the microring and the F-P resonator is more relaxed. The two most important properties of the EIT-like transmission namely the insertion loss (IL) and the full-width-at-half-maximum (FWHM) have been analytically investigated by utilizing the specially developed model based on the transfer matrix method. The APMR-BG based coupling resonant system was fabricated on a silicon-on-insulator (SOI) platform. The EIT-like transmission with an extinction ratio (ER) of 12 dB, a FWHM of 0.077 nm and a quality factor (Q factor) of 20200 was achieved, which agree well with the simulated results based on our numerical model. A slow light with a group delay of 38 ps was also obtained.

Optics Express•Oct 26, 2016•26 citations

Tunable electromagnetically induced transparency in integrated silicon photonics circuit

Ang Li, Wim Bogaerts

We comprehensively simulate and experimentally demonstrate a novel approach to generate tunable electromagnetically induced transparency (EIT) in a fully integrated silicon photonics circuit. It can also generate tunable fast and slow light. The circuit is a single ring resonator with two integrated tunable reflectors inside, which form an embedded Fabry-Perot (FP) cavity inside the ring cavity. The mode of the FP cavity can be controlled by tuning the reflections using integrated thermo-optic tuners. Under correct tuning conditions, the interaction of the FP mode and the ring resonance mode will generate a Fano resonance and an EIT response. The extinction ratio and bandwidth of the EIT can be tuned by controlling the reflectors. Measured group delay proves that both fast light and slow light can be generated under different tuning conditions. A maximum group delay of 1100 ps is observed because of EIT. Pulse advance around 1200 ps is also demonstrated.

Optics Express•Dec 5, 2017•43 citations
Microring resonators (MRRs) are key building blocks in integrated photonics, but their performances usually suffer from limitations in extinction ratio and slope rate (SR), primarily due to their symmetrical Lorentzian resonance line shape. To overcome these limitations, special transmission spectra (STS), such as Fano resonance and electromagnetically induced transparency (EIT)-like resonance, offer asymmetric line shapes that exhibit a higher extinction ratio (ER) and a steeper SR, thereby enhancing the sensitivity and selectivity of optical switches, filters, and high-sensitivity sensors. However, the current reported works typically achieved only one type of STS and had limited tunability. In this Letter, we experimentally demonstrate a novel, to the best of our knowledge, device using two cascaded MRRs with different quality factors to generate Fano and EIT-like resonances at distinct ports. The ER can reach up to 31.2 dB with a sharp SR of 130.1 dB/ nm, for Fano resonance, and the EIT-like resonance is 12.4 dB. By adjusting the resonator wavelength of the MRRs and the phase shifter, the STS can be working at any desired wavelength. The device is demonstrated on a silicon-on-insulator platform, offering versatile application potential in optical sensors, slow and fast light generation, and microwave photonics.
We propose and demonstrate an on-chip coupling resonant system to generate electromagnetically induced transparency (EIT)-like effect and Fano resonance on silicon platform. It is composed of a microring resonator (MRR) and two cascaded Sagnac-loop mirrors (SLMs) assisted Fabry-Perot (FP) cavity on silicon-on-insulator. According to the coupling conditions of the MRR, two cases are studied theoretically. When the MRR is over coupling, EIT-like transmission can be observed. In contrast, Fano resonances can be generated by the condition of under coupling. In the experiment, the add-drop MRR is under coupling, leading to a sharp asymmetric line shape for Fano resonance. The resonance wavelength of the MRR can be dynamically tuned based on thermal-optic effects by tuning the micro-heater. The experiment results show Fano resonances with maximum extinction ratio (ER) of 23.22 dB and maximum slope rate (SR) of 252 dB/nm. Moreover, the wavelength of Fano resonance can be shifted widely with a tuning efficiency of 0.2335 nm/mW.
By breaking the symmetrical arrangement of double micro-ring resonator, the formation mechanism and performance of reflection and transmission spectrum and optical field distribution are investigated. The reflection spectrum is Fano shape. The Fano resonance has an asymmetric and sharp resonance peak can be independently tuned by changing the asymmetric coupling factor of the first micro-ring. The transmission spectrum is electromagnetically induced transparency(EIT)-like shape. The (EIT)-like resonance can be independently tuned by changing the absorption factor and the phase shift factor of the second micro-ring. The Fano and EIT-like resonance have low loss and high near-field localization characteristics, our research has promising applications in optical communication and opto-electronic modulators.
A conversion between the electromagnetically induced transparency (EIT) transmission and Fano transmission is theoretically and experimentally demonstrated in an all-pass microring-Bragg grating (APMR-BG) coupled-resonator system. In this work, the coupling between the two resonators (the microring resonator and the Fabry-Perot resonator formed by two Bragg gratings) gives rise to the EIT and Fano transmissions. The resonant status strongly depends on the round-trip attenuation of the microring and the coupling strength. By tuning the coupling strength, the EIT and Fano transmissions can be controlled and converted. The device performance has been theoretically calculated and analyzed with a specially developed numerical model based on the transfer matrix method. The APMR-BG coupled-resonator systems with different gap widths were designed, fabricated, and characterized on a silicon-on-insulator (SOI) platform. The conversion of resonance was experimentally observed and verified. In addition, this on-chip system has the advantage of a small footprint, and the fabrication process is compatible with the planar waveguide fabrication process.
In this paper, we realize tunable Fano and electromagnetically induced transparency (EIT)-like resonances in the outputs of a nested feedback ring resonator. Compared with the traditional add-drop ring resonator, the feedback arm introduces interference between different resonance modes. Using coupled mode theory, we reveal that the output Fano resonances are the interference of discrete modes and continuum modes, whereas the EIT-like resonance only appears in the over-coupled state. We experimentally confirm the two effects using optical fiber ring resonators, finding that the Fano effect can be easily controlled with phase shifts in the feedback arm. Moreover, we achieve the double Fano resonance, which displays an ‘X’ type lineshape utilizing one ring resonator, predicting it to be a good candidate in wavelength monitor. The proposed simple configuration provides a platform to study Fano and EIT-like effect, which is useful in the optical filter, fast and slow light, optical switching, and optical sensing.
An all-pass microring-Bragg gratings (APMR-BG) based coupling resonant system is proposed and experimentally demonstrated to generate electromagnetically induced transparency (EIT)-like transmission for the first time. The coupling between two light path ways in the micro-ring resonator and the Fabry-Pérot (F-P) resonator formed by two sections of Bragg gratings gives rise to the EIT-like spectrum. This system has the advantage of a small footprint consisting of only one microring resonator and one bus waveguide with Bragg gratings. It also has a large fabrication tolerance as the overlap requirement between the resonance wavelengths of the microring and the F-P resonator is more relaxed. The two most important properties of the EIT-like transmission namely the insertion loss (IL) and the full-width-at-half-maximum (FWHM) have been analytically investigated by utilizing the specially developed model based on the transfer matrix method. The APMR-BG based coupling resonant system was fabricated on a silicon-on-insulator (SOI) platform. The EIT-like transmission with an extinction ratio (ER) of 12 dB, a FWHM of 0.077 nm and a quality factor (Q factor) of 20200 was achieved, which agree well with the simulated results based on our numerical model. A slow light with a group delay of 38 ps was also obtained.
We comprehensively simulate and experimentally demonstrate a novel approach to generate tunable electromagnetically induced transparency (EIT) in a fully integrated silicon photonics circuit. It can also generate tunable fast and slow light. The circuit is a single ring resonator with two integrated tunable reflectors inside, which form an embedded Fabry-Perot (FP) cavity inside the ring cavity. The mode of the FP cavity can be controlled by tuning the reflections using integrated thermo-optic tuners. Under correct tuning conditions, the interaction of the FP mode and the ring resonance mode will generate a Fano resonance and an EIT response. The extinction ratio and bandwidth of the EIT can be tuned by controlling the reflectors. Measured group delay proves that both fast light and slow light can be generated under different tuning conditions. A maximum group delay of 1100 ps is observed because of EIT. Pulse advance around 1200 ps is also demonstrated.