Bidirectional switchable beam splitter/filter based graphene loaded Si ring resonators

Abstract

Using bus waveguides coupled to the graphene-loaded Si-ring resonators (GSRRs) all on a Si-‎on-insulator substrate, we propose a compact bidirectional switchable beam splitter/filter ‎controlled by graphene-based electro-absorptive (refractive) mode modulation. The proposed ‎device consists of a through waveguide coupled to two drop waveguides via two GSRRs. ‎Each GSRR consists of a stack of hBN/graphene/hBN nanolayers sandwiched between two ‎Si-ring resonators. Using a finite difference time domain method, we show that the resonant ‎wavelength of GSRRs can be tuned in the range of 1551.5 < λ <1552.1 nm, linearly with the ‎slope of ~2.46 nm/eV via appropriately changing the graphene chemical potential, ‎electrostatically. The numerical results show that when both GSRRs are in an electro-refractive ‎state and a transverse electric (TE) polarized light beam of an appropriate wavelength is ‎launched into one of the though-ports, ~ 84.5% of the input intensity equally splits between ‎the adjacent drop-ports. The transmission out of the second through-port is less than 0.8%. ‎The numerical results further show that when one GSRR is in an electro-refractive mode, and ‎the other one is in an electro-absorptive state, ~68.4% of the input intensity transmits out of ‎the drop-port adjacent to the former GSRR, and the other ports experience insignificant ‎outputs (<0.7%). The device's structural symmetry makes it a bidirectional tunable, suitable for ‎long-haul optical telecommunication applications.‎

Design of Photonic-Molecule-Based Multiway Beam Splitter/Coupler with Variable Division Ratio

“…Dielectric microresonators have long been actively used in disk lasers [1], high-resolution spectroscopy [2], laser frequency stabilization [3], add-drop filters for compact wavelength division (de)multiplexing [4,5], dispersion compensation of optical fiber transmission lines [6], implementation of all-optical switching for optical signals [7,8], optical nodes of quantum computers [9], as well as beam power dividers [10,11] and inertia-free optical couplers [12,13].…”

“…Recently, optical splitters based on planar disk or ring traveling/standing wave resonators realized as an integrated element inside photonic crystals [8,15] or directly on a silicon-on-insulator (SOI) platform [4,5,19] have become widespread. Typically, such splitters function in a narrow spectral range near the eigenmode resonances of a microcavity, when the incoming optical radiation is coupled to the resonant modes and redirected into signal collection channels (drop ports).…”

“…The most common structural design of resonant beam splitters (RBS) is usually composed of several high-quality (high-Q) resonant DOEs (ring, disk, microcylinder, microsphere) coupled to the commutation buses in the form of rectangular or cylindrical waveguides forming the through and drop-ports of the optical signal output. The resonators themselves are usually in close subwavelength contact with each other in a serial [4] or parallel structural topology [5,20]. In optical splitters based on multimode interaction, the interconnection of resonant elements and waveguide buses is realized by indirect coupling of evanescent electromagnetic fields of the eigenmodes.…”

“…Unlike similar metasurface-based beam dividers [33,34] in terms of the functionality, the proposed beam splitter is much simpler and cheaper in fabrication, suitable for the "System-on-a-chip" integration, and can dynamically change its power splitting ratio by spectrally tuning to a different resonant supermode of the constituting PM. Moreover, another advantage of the proposed RBS is its ultra-compact design with the dimensions typically not exceeding several optical wavelengths as compared to the optical splitter based on ring resonators [5].…”

Nonlocal Timoshenko shear beam model for multilayer curved graphene nano-switches

“…Because of its exceptional mechanical, electrical, chemical, and thermal capabilities, graphene sheets have a wide range of potential uses, including those in reinforced materials [1,2], gas sensors [3], mass sensors [4], oscillator [5], resonators [6,7], and nano-electromechanical switches [8][9][10]. Graphene is a single-atom-thick planar structure that may be monolayer or multilayer.…”