Abstract
Graphene has emerged as an ultrafast photonic material for on-chip photodetection. However, its atomic thickness limits its interaction with guided optical modes, which in turn weakens the photoresponse of waveguide-integrated graphene photodetectors. Nonetheless, it is possible to enhance the interaction of guided light with graphene by nanophotonic means. Herein, we propose a practical design of a plasmon-enhanced photovoltaic double-graphene detector that is integrated into 5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m long titanium nitride slot waveguides. The use of double-graphene in this configuration yields a high responsivity of 2.18 A/W and more for a 0.5 V bias, across the telecom C-band and beyond. Moreover, the device operates at an ultra-high-speed beyond 100 GHz with an ultra-low noise equivalent power of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$<\!35\,$</tex-math></inline-formula> pW/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sqrt{\text{Hz}}$</tex-math></inline-formula> . The reported features are highly promising and are expected to serve the needs of next-generation optical interconnects.
Highlights
G RAPHENE is a two-dimensional (2D) material that consists of one layer of carbon atoms that are arranged in a honeycomb lattice [1]
Its 2D nature enables its facile with silicon photonics (SiPh) and microelectronics using complementary metal oxide semiconductor (CMOS) processes [3], [4]
We propose a plasmon-enhanced photovoltaic double-graphene detector that is integrated into titanium nitride (TiN) slot waveguides
Summary
G RAPHENE is a two-dimensional (2D) material that consists of one layer of carbon atoms that are arranged in a honeycomb lattice [1]. The ultrafast response of these photodetectors is highly desirable for next-generation telecom and datacom networks, where photonic devices with a bandwidth beyond 100 Gigabits per second (Gbps) are required [8]. Despite this outstanding performance, the atomic thickness of graphene limits its interaction with guided optical modes, resulting in a relatively low current responsivity in the range of several mA/W [9]. The atomic thickness of graphene limits its interaction with guided optical modes, resulting in a relatively low current responsivity in the range of several mA/W [9] To overcome this limitation, plasmon-enhanced graphene photodetectors have been proposed and demonstrated in [5], [7], [10]–[17], where a record-high
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