Single-layer graphene sheet and annular resonant cavity-based surface plasmon Mach-Zehnder interferometer

Abstract

The invention provides a single-layer graphene sheet and annular resonant cavity-based surface plasmon Mach-Zehnder interferometer. The single-layer graphene sheet and ring-shaped resonant cavity-based surface plasmon Mach-Zehnder interferometer includes an environmental medium (silica), a graphene input waveguide, a graphene output waveguide, a first annular resonant cavity, a second annular resonant cavity, an interferometer upper arm and an interferometer lower arm. The single-layer graphene sheet and annular resonant cavity-based surface plasmon Mach-Zehnder interferometer is characterized in that the graphene waveguides and the resonant cavities are fixed in the environmental medium (silica); and a voltage adjustable region of which the length is 200 nm is arranged in the interferometer upper arm. When the single-layer graphene sheet and annular resonant cavity-based surface plasmon Mach-Zehnder interferometer is used, optical signals are guided to the graphene input waveguide through a coupling silicon waveguide or a tapered optical fiber, and are coupled into the interferometer upper arm and the interferometer lower arm through the first annular resonant cavity; and externally-applied voltage of the voltage adjustable region of the interferometer upper arm is adjusted so as to vary from 0.1eV to 0.5eV, and therefore, the optical distance of the optical signals transmitted on the interferometer upper arm can be changed, and finally, the interference of the optical signals in the graphene output waveguide can be strengthened or weakened. The single-layer graphene sheet and annular resonant cavity-based surface plasmon Mach-Zehnder interferometer of the invention is simple in structure and small in size, and is active and adjustable; the single-layer graphene sheet and annular resonant cavity-based surface plasmon Mach-Zehnder interferometer can be applied to infrared bands, and has a bright application prospect in the aspects of optical communication, optical integration and optical information processing.

Description

technical field [0001] The invention relates to a micro-nano optical device, in particular to a surface plasmon Mach-Zehnder interferometer based on a single-layer graphene sheet and a ring resonant cavity. Background technique [0002] Surface plasmon waveguide devices have many advantages, such as simple and compact structure, small size, not limited by the diffraction limit, and provide the possibility of compatibility between electronic circuits and photonic devices. In many fields, especially optical integration, optical computing and optical information processing and other fields, has broad application prospects. [0003] In the THz band and infrared band, photons can be easily coupled into graphene to generate surface plasmon waves, which can be modulated by modulating voltage and doping. The energy consumption is also very low, and it can be modulated in different TM mode and TE mode are supported respectively, which makes graphene a popular choice for surface plas...

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Problems solved by technology

[0004] Surface plasmon Mach-Zehnder interferometer, as an important integrable photonic device, effectively solves the shortcomings of traditional M-Z interferometers, which are limited by the diffraction limit, resulting in bulky size and difficulty in integration.

Surface plasmon is a coherent resonance formed by an external electromagnetic field and free electrons on the metal surface. The incident light energy is mainly bound on the metal surface and propagates forward. It can effectively overcome the diffraction limit and provide a new way for the development of micro-nano photonic devices. approach, but the traditional Mach-Zehnder interferometer made of metal as surface plasmon waveguide material, on the one hand, has relatively large energy consumption, and on the other hand, because the metal dielectric constant is not adjustable, when its structure is fixed, it is difficult to realize Active tuning of Mach-Zehnder interferometers

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