High-efficiency graphene-silicon slot-waveguide microring modulator at 1.5 {\mu}m and 2 {\mu}m wavelength bands

TL;DR

This paper presents a graphene-silicon slot-waveguide microring modulator achieving high efficiency and broad bandwidth at 1.5 and 2 micrometers, suitable for advanced optical communication applications.

Contribution

It introduces a novel integrated electro-optic modulator with a double-layer graphene on a silicon microring, combining high modulation efficiency with wide bandwidth in a compact device.

Findings

At 1550 nm, VπL = 220 V·μm, bandwidth >70 GHz, OMA = -1.97 dBm at 3 V.

At 2 μm, bandwidth >20 GHz, OMA = -3.36 dBm at 6 V, with open eye diagrams at 20 Gbit/s.

Operates effectively at both 1.5 μm and 2 μm wavelengths, demonstrating broadband performance.

Abstract

Electro-optic (E/O) modulators are crucial for optical communication but face a trade-off between modulation bandwidth and efficiency. A small footprint could reduce the capacitance and increase the bandwidth, however, this usually results in a low modulation efficiency. Here, we present an integrated E/O modulator that simultaneously achieves wideband large bandwidth and high modu- lation efficiency operation by embedding a partially overlapped double-layer graphene on a compact silicon slot waveguide microring resonator. At 1550 nm, the graphene-silicon slot-waveguide demon- strates a high phase modulation efficiency of V{\pi} L = 220 V {\mu}m, and the corresponding microring modulator has a large bandwidth of over 70 GHz, a compact active length of 10 {\mu}m, and an optical modulation amplitude (OMA) of -1.97 dBm under a 3-V voltage swing. The modulator operates at a data rate of 50 Gbit/s with an open eye diagram under a 2-V Vpp RF drive voltage. The graphene modulator operation is broadband, and we also characterize its performance at 2 {\mu}m wavelength band. At 2 {\mu}m wavelength band, the microring modulator has a large bandwidth of over 20 GHz, an OMA of -3.36 dBm under a 6-V voltage swing, and an open eye diagram at 20 Gbit/s with a 2-V Vpp RF drive voltage. The difference in performance is caused by the bandwidth limit of the 2 {\mu}m wavelength band measurement setup. The broadband, large bandwidth, compact, highly effi- cient, and energy efficient graphene E/O modulator has the potential to enable large-scale graphene photonic integrated circuits, facilitating a broad range of applications such as optical interconnects, optical neural networks, and programmable photonic circuits.