All-Dielectric Graphene-induced T-Slot Waveguide Electro-Optic Modulator With Polarization-Independent Operation

Abstract

Developing efficient techniques to realize polarization-independent modulators nowadays is still important for on-chip photonic circuits. Here, we propose and theoretically demonstrate a graphene-based T-slot waveguide modulator, which simultaneously supports the TE and TM polarized modes, offering a greater possibility to achieve the polarization-independent modulation. The modulation performance is comprehensively studied in terms of attenuation loss, insertion loss, modulation depth, normalized mode area, bandwidth and power consumption. Optimizations of key characteristic parameters illustrate that the modulator not only offers a mode confinement beyond the diffraction limit (<; λ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /12 and <; λ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /8 for TM and TE modes, respectively), but also exhibits an outstanding performance with a modulation depth (MD) of >0.35 dB/μm, a insertion loss (IL) of <; 0.1 dB/μm and a MD discrepancy of <; 0.012 dB/μm for both polarized modes covering the whole S, C and L bands. Particularly, the modulator possesses a compact footprint of 11.6 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , a 3-dB modulation bandwidth of 50 GHz and a power consumption per bit of 2.07 pJ/bit based on theoretical predictions. The polarization-independent operation is also quite robust against the possible fabrication perturbations. Our work may inspire new potential for developing the integrated modulators and opto-electronic interconnects in the advanced polarization-diversity circuits.