Abstract
Graphene has been widely utilized in optoelectronic applications due to its high carrier mobility, and extremely fast optical response. Microcavity-integrated graphene waveguide structure is one basic module of integrated photonic devices which can greatly improve the light-matter interaction strength. The enhanced optical absorption in the undoped graphene layer results from the light trapping and the corresponding long light-graphene interaction length. Tuning the Fermi energy level of the graphene layer enables the electro-optical modulation. We report the realization of reconfigurable electro-optical attenuator and switch with unity-order modulation depth in light reflection and transmission at near-infrared frequency. The transformation from a lossy absorber to a quasi-perfect transparent condition of the monolayer graphene by tuning the Fermi level leads to the unity-order tunability of the electro-optical attenuator and switch. We investigate theoretically and numerically the absorption properties of the designed microcavity-integrated graphene with respect to different graphene Fermi levels. Electro-optical attenuator with attenuating coefficient from 10% to 98.29% is fulfilled. On-off electro-optical switching with a switching contrast larger than 21 dB is demonstrated. Our approach provides the possibilities of graphene photonics applied in communications, and sensing.
Highlights
The intriguing optoelectronic and photonic properties of graphene has led to an increasing research interest in utilizing graphene for electro-optical applications
We investigate the tunability of reflection\transmission properties of a microcavity-integrated graphene waveguide structure by comprehensively studying the interaction between the monolayer graphene and the microcavity under different graphene Fermi levels in the near-infrared region to achieve reconfigurable electro-optical attenuator and switch
The absorption coefficient of a monolayer graphene depends on its unique band structure and many other parameters including scattering rate, operating temperature, electron velocity, as well as electric and magnetic field bias[15,16,17,18,19,20,21,22]
Summary
The intriguing optoelectronic and photonic properties of graphene has led to an increasing research interest in utilizing graphene for electro-optical applications. We investigate the tunability of reflection\transmission properties of a microcavity-integrated graphene waveguide structure by comprehensively studying the interaction between the monolayer graphene and the microcavity under different graphene Fermi levels in the near-infrared region to achieve reconfigurable electro-optical attenuator and switch.
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