Journal of Lightwave Technology

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

Kai Ma, Yundong Zhang, Huaiyin Su, Guo Yi, Changqiu Yu, Yongfeng Wu

Published Apr 2, 2021• 15 citations

Abstract

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.

DOI: 10.1109/jlt.2021.3070748

Related papers

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

Xudong Zhou, Mingrui Yuan, Shijing Qin +7 more

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.

Optics LettersMar 24, 20255 citations

Fano-Like Resonance in an All-in-Fiber Structure

Biqiang Jiang, Xuetao Gan, Linpeng Gu +6 more

We achieve Fano-like resonances in an all-in-fiber structure embedded with an in-line Mach-Zehnder interferometer (MZI). A fiber Bragg grating is inserted into MZI's one arm to form a resonance, which functions as the discrete state of the Fano-like resonance to couple with the continuum propagating mode of MZI in the fiber core. A theoretical model predicts the controllable resonance lineshape by changing the phase difference between the MZI's two interference pathways. Fano-like resonances with an extinction ratio over 20 dB are experimentally observed, which are reliably tuned into Lorentzian and electromagnetically induced transparency-like resonances by versatile methods. The realization of Fano-like resonances with broad tunability in this all-in-fiber structure holds potentials in fiber-based applications of sensing, signal processing and nonlinear optics.

IEEE photonics journalAug 22, 201936 citations

Stable controlling of electromagnetically induced transparency-like in a single quasi-cylindrical microresonator

Xueying Jin, Yongchao Dong, Keyi Wang

We experimentally and theoretically demonstrate electromagnetically induced transparency (EIT)-like and Fano resonance in a single quasi-cylindrical microresonator (QCMR). Stable controlling of the EIT and Fano resonance lineshapes can be achieved by vertically moving the resonator along its axis while in touch with the tapered fiber. Moreover, by horizontally scanning the coupling point along the tapered fiber, asymmetric Fano resonances of the transmission spectra are observed and can be engineered to vary periodically. Interestingly, the two different kinds of mechanisms that induce the Fano or EIT resonances can work on the same mode simultaneously. Our device offers a stable platform for controlling the EIT and Fano resonances and holds unique potential in all-optical switching, quantum information processing and sensitivity-enhanced sensing applications.

Optics ExpressDec 14, 201621 citations

Tunable Fano resonances in a robust quasicylindrical microresonator photonic system

Xueying Jin, Mengyu Wang, Yongchao Dong +3 more

The control of Fano resonances is of critical importance to opto-electronic and all-optical switching devices, light delay and storage, high sensitivity sensors, and quantum information processors. In this paper, we experimentally and theoretically demonstrate that controllable electromagnetically induced transparency (EIT)-like and Fano resonances can be achieved in a single quasi-cylindrical microresonator (QCMR). Robust and selective excitation of localized axial modes in a high quality QCMR is firstly demonstrated. Based on this stable platform, EIT-like lineshapes can be tuned and converted into Fano resonances by vertically moving the resonator. Moreover, by horizontally scanning the resonator, the transmission spectrum exhibits periodically changed Fano-like lineshapes. It is reported for the first time that the above two kinds of Fano resonances originated from different mechanisms can work on the same mode simultaneously. Our approach, demonstrated in this work, provides a robust photonic platform for accessing, controlling, and engineering the Fano resonances.

MATEC Web of ConferencesJan 1, 20180 citations

Electromagnetically induced-transparency-like spectrum in an add/drop interferometer

Kaiyang Wang, Changqiu Yu, Xuenan Zhang +3 more

We propose a single-ring-resonator-based add/drop interferometer and theoretically investigate the transmission characteristics. Due to coherent interference of two resonant pathways, an electromagnetically induced-transparency (EIT)-like spectrum is produced and the line shapes of the transmission spectra are tunable by controlling the coupling coefficients between the waveguide and ring resonator. We observe the EIT-like behavior in a fiber system which agrees well with the theoretical analysis. The proposed configuration has potential applications in tunable delay lines.

Applied OpticsFeb 10, 20158 citations

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 ExpressOct 9, 201761 citations