Graphene electro-optical modulator based on high-Q-value annular resonant cavity

Abstract

The invention provides a graphene electro-optical modulator based on a high-Q-value annular resonant cavity. The graphene electro-optical modulator based on the high-Q-value annular resonant cavity comprises a high-Q-value annular resonant system. A part of the perimeter of an annular waveguide of the high-Q-value annular resonant system is adopted for covering and manufacturing a double-layer graphene thin film modulation system. The double-layer graphene thin film modulation system comprises a bottom layer dielectric layer, bottom layer graphene, a middle dielectric layer and top layer graphene. A voltage V(t) is added between the top layer graphene and the bottom layer graphene. According to the modulator, material advantages such as high broadband absorption and carrier mobility of graphene and the structure advantage of optical path amplification of the high-Q-value annular optical resonant cavity are integrated, the modulation depth is increased, the maximum modulation frequency is increased in the mode that RC delay is reduced through reduction of the area of the graphene, and therefore the problem that the modulation depth and the modulation bandwidth in an existing straight waveguide graphene modulator are decreased and increased alternately is solved. The 3dB bandwidth can reach the modulation frequency of over 100 GHz expectantly.

Description

technical field [0001] The invention relates to the technical field of optical instruments, in particular to a graphene electro-optic modulator based on a high-Q ring resonant cavity. Background technique [0002] Graphene is a two-dimensional crystal composed of carbon atoms. The light absorption ratio of single-layer graphene atoms is 2.3%. Because graphene has a zero-gap valence band structure, its meter energy level position can be controlled by voltage to modulate It absorbs light. It has been reported (see Ming Liu et.al, "A graphene –based broadband optical modulation" Nature No.474, pp 64-67, 2011) that the photoelectric modulator made of single-layer graphene and straight waveguide structure, It can completely absorb light waves with a wavelength range of 1.3-1.6 microns. Since the straight waveguide does not have frequency-selective characteristics, it is actually a kind of "blind absorption" and does not have frequency-selective characteristics. [0003] The res...

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Problems solved by technology

[0003] The research results of Steven J. et al. (Steven J. Koester, Mo Li, "High-speed waveguide-coupled graphene-on-graphene optical modulators" Appl. Optical Modulator Phys. Lett. 100 (171107), 2012), graphite The 3dB bandwidth of ene can theoretically reach 120GHz, and the latest structure proposed by Liu Ming et al. (Ming Liu, et.al, “Double-Layer Graphene Optical Modulator” Nano Lett.12(3), pp 1482–1485, 2012) The proposed graphene / straight waveguide optical modulator structure has a modulation frequency of 1 GHz, and there is still a huge gap between their experimental results and theory

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