Multimode Ring Resonator Research Articles

Entangling Interactions Between Artificial Atoms Mediated by a Multimode Left-Handed Superconducting Ring Resonator

Superconducting metamaterial transmission lines implemented with lumped circuit elements can exhibit left-handed dispersion, where the group and phase velocity have opposite sign, in a frequency range relevant for superconducting artificial atoms. Forming such a metamaterial transmission line into a ring and coupling it to qubits at different points around the ring results in a multimode bus resonator with a compact footprint. Using flux-tunable qubits, we characterize and theoretically model the variation in the coupling strength between the two qubits and each of the ring-resonator modes. Although the qubits have negligible direct coupling between them, their interactions with the multimode ring resonator result in both a transverse exchange coupling and a higher-order ZZ interaction between the qubits. As we vary the detuning between the qubits and their frequency relative to the ring-resonator modes, we observe significant variations in both of these interqubit interactions, including zero crossings and changes of sign. The ability to modulate interaction terms such as the ZZ scale between zero and large values for small changes in qubit frequency provides a promising pathway for implementing entangling gates in a system capable of hosting many qubits. Published by the American Physical Society 2024

High-order exceptional points and novel light transmission spectra in [formula omitted] symmetric ring resonator array

In this paper we construct PT symmetric 1D multi-mode ring resonator arrays to study the high-order exceptional points and related light transmission spectra. We first focus on arrays with the underling symmetry given by SU(2) group possessing high-order exceptional points (EPs). The Gilmore-Perelomov coherent state approach has been well tested in SU(2) symmetric waveguide array, but how this approach is applied in resonator arrays, and how the divergent peaks change near high-order EPs is still remains to be seen. After the study on SU(2) symmetric arrays, we change the coupling coefficients to a uniformed value, and the high-order EP splits into several lower order EPs, thus the original clear boundary between the PT unbroken and broken regions is replaced by a transition region, wherein we observe some interesting results such as multi-number of non-divergent peaks and the coexistence of divergent and non-divergent peaks.

Compact and high Q-factor multimode racetrack ring resonator based on transformation optics.

The ring resonator is a versatile and functional component in the silicon-based integrated optical circuit. Most of the previously reported ring resonators work in the single-mode case. With the rapid development of mode division multiplexing technology, a multimode ring resonator (MMRR) has been proposed and the usage beyond the limit of a conventional single mode ring resonator has been explored. However, the reported MMRRs are either large in size or low in quality factor. In this paper, we designed a compact silicon MMRR with a small bending radius of 15µm, in which the three lowest TE modes all have high Q-factors. For suppressing the mode loss and inter-mode crosstalk in MMRR, a multimode waveguide bend (MWB) with mode adiabatic evolution was designed based on transformation optics and waveguide shape optimization. The independent excitation of each order mode of the MMRR is realized by using bending directional coupler and asymmetric directional coupler. We successfully fabricated the device on a silicon-on-insulator (SOI) platform using simple one-step lithography. The measured loaded Q-factors of the three lowest TE modes are 5.9 × 104, 4.5 × 104, and 4.7 × 104, respectively.

Silicon integrated multi-mode ring resonator

Abstract Ring resonator is an essential element in silicon integrated circuit, it is widely used as filter, wavelength multiplexer and switch in single-mode operation regime. As the rapid development of mode division multiplexing (MDM) technique, ring resonator that can process multi-mode signals simultaneously and uniformly is highly desired. However, the severe modal dispersion makes identical transmission for different modes very hard. In this paper, by breaking through the limitation of conventional multi-mode manipulation design with evanescent coupling or mode interference, we propose and demonstrate a multi-mode ring resonator (MMRR) inspired by the free space geometric optics. Arbitrary number of supporting modes can be achieved by simply widening the waveguide width. For proof-of-concept demonstration, an MMRR supporting four modes is fabricated with uniform transmittance. Furthermore, architecture of cascaded four MMRRs are also demonstrated experimentally.

Hundred megahertz microwave photonic filter based on a high Q silicon nitride multimode microring resonator

Narrowband microwave photonic filters based on a microring resonator are difficult to achieve because low cavity loss and low coupling loss should be satisfied simultaneously. Here, a high Q (∼2.6×106) multimode microring resonator is proposed to achieve an ultra-narrow band tunable microwave photonic filter. Combining the ultra-low loss of the silicon nitride waveguide and the ultra-low coupling coefficients of the multimode ring resonator, very narrow optical bandwidths between 72.5 MHz to 275 MHz were obtained for different order modes, which match the simulation results well. Furthermore, by introducing the two switchable modulation methods supported by the dual-drive Mach–Zehnder modulator, we achieved a narrowband passband/stopband switchable microwave photonic filter, whose 3 dB bandwidths are 180 MHz and 120 MHz, respectively. The filter frequency can be tuned from 2 ∼ 18 GHz by altering the laser wavelength, and a high out of band RF rejection ratio about 27 dB was obtained for the passband filter due to the high-quality factor. Besides, a high RF rejection ratio of about 51 dB was achieved for the stopband filter by using the RF cancellation technology.

Miniaturized Ring Resonator Wideband Bandpass Filter with Wide Stop Band

In this paper miniaturized quarter wavelength rectangular shaped multimode ring resonator bandpass filter with extended diagonal corners and internally located high impedance perturbation stubs, is proposed. Input/output open stubs are tightly coupled to the extended diagonal corners running parallel to the two sides of the ring resonator, implemented to generate wide passband and wide stop-band. Cut-off frequencies can be shifted to the higher side by increasing the length of the sides of resonator. By inserting the perturbation stubs, rectangular ring resonator produces three degenerate modes out of which first two form a wide passband. Small square patch is attached to the opposite interior corners of the ring resonator and T-shaped stub attached to the opposite longer side of the resonator are tightly coupled with feeder line to improve the return loss, insertion loss and skirt-characteristics. Shorter sides of the rectangular ring resonator are bent in U-shaped to increase the effective length of the resonator eventually the bandwidth is widened. Filter is designed and simulated for the center frequency of 3.2 GHz, bandwidth from 2.0 GHz to 4.0 GHz, on dielectric constant 3.38 and thickness 0.508 mm. Electromagnetic simulator Ansoft HFSS is used to optimize the filter dimensions.

Miniaturized Ring Resonator Wideband Bandpass Filter with Wide Stop Band

In this paper miniaturized quarter wavelength rectangular shaped multimode ring resonator bandpass filter with extended diagonal corners and internally located high impedance perturbation stubs, is proposed. Input/output open stubs are tightly coupled to the extended diagonal corners running parallel to the two sides of the ring resonator, implemented to generate wide passband and wide stop-band. Cut-off frequencies can be shifted to the higher side by increasing the length of the sides of resonator. By inserting the perturbation stubs, rectangular ring resonator produces three degenerate modes out of which first two form a wide passband. Small square patch is attached to the opposite interior corners of the ring resonator and T-shaped stub attached to the opposite longer side of the resonator are tightly coupled with feeder line to improve the return loss, insertion loss and skirt-characteristics. Shorter sides of the rectangular ring resonator are bent in U-shaped to increase the effective length of the resonator eventually the bandwidth is widened. Filter is designed and simulated for the center frequency of 3.2 GHz, bandwidth from 2.0 GHz to 4.0 GHz, on dielectric constant 3.38 and thickness 0.508 mm. Electromagnetic simulator Ansoft HFSS is used to optimize the filter dimensions.

High-Temperature Superconducting Multimode Ring Resonator Ultrawideband Bandpass Filter

This letter presents a new multimode ring resonator ultrawideband (UWB) bandpass filter by loading a microstrip line on the vertical symmetrical plane of a ring resonator and a pair of stepped-impedance open stubs at the center of this microstrip line. Five modes are allocated within UWB band, and a pair of transmission zeros are introduced to improve the passband selectivity. By adopting the parallel-coupled lines, not only suitable external coupling is achieved, but also the performance of upper stopband is improved. This quintuple-mode high-temperature superconducting UWB filter is designed on a 0.5-mm-thick MgO substrate with double-sided YBCO films. The measured results show that 3-dB bandwidth covers 1.57–6.51 GHz, the return loss is better than 10.70 dB, the out-of-band rejection is greater than 24.75 dB in the lower stopband, and the upper stopband with 20-dB attenuation level is extended to about 9 GHz.

Synthetic Landau levels for photons.

Synthetic photonic materials are an emerging platform for exploring the interface between microscopic quantum dynamics and macroscopic material properties. Photons experiencing a Lorentz force develop handedness, providing opportunities to study quantum Hall physics and topological quantum science. Here we present an experimental realization of a magnetic field for continuum photons. We trap optical photons in a multimode ring resonator to make a two-dimensional gas of massive bosons, and then employ a non-planar geometry to induce an image rotation on each round-trip. This results in photonic Coriolis/Lorentz and centrifugal forces and so realizes the Fock–Darwin Hamiltonian for photons in a magnetic field and harmonic trap. Using spatial- and energy-resolved spectroscopy, we track the resulting photonic eigenstates as radial trapping is reduced, finally observing a photonic Landau level at degeneracy. To circumvent the challenge of trap instability at the centrifugal limit, we constrain the photons to move on a cone. Spectroscopic probes demonstrate flat space (zero curvature) away from the cone tip. At the cone tip, we observe that spatial curvature increases the local density of states, and we measure fractional state number excess consistent with the Wen–Zee theory, providing an experimental test of this theory of electrons in both a magnetic field and curved space. This work opens the door to exploration of the interplay of geometry and topology, and in conjunction with Rydberg electromagnetically induced transparency, enables studies of photonic fractional quantum Hall fluids and direct detection of anyons.