Enhanced self-phase modulation in silicon nitride waveguides integrated with 2D graphene oxide films

TL;DR

This paper demonstrates that integrating 2D graphene oxide films onto silicon nitride waveguides significantly enhances self-phase modulation, leading to greater spectral broadening and improved nonlinear optical performance.

Contribution

The study introduces a solution-based transfer-free method to integrate graphene oxide films onto Si3N4 waveguides, significantly boosting their nonlinear optical properties.

Findings

Spectral broadening factor of up to 3.4 with 2 layers of GO

Nonlinear parameter improved by up to 18.4 times

GO Kerr coefficient is about 5 orders of magnitude higher than Si3N4

Abstract

We experimentally demonstrate enhanced self-phase modulation (SPM) in silicon nitride (Si3N4) waveguides integrated with 2D graphene oxide (GO) films. GO films are integrated onto Si3N4 waveguides using a solution-based, transfer-free coating method that enables precise control of the film thickness. Detailed SPM measurements are carried out using both picosecond and femtosecond optical pulses. Owing to the high Kerr nonlinearity of GO, the hybrid waveguides show significantly improved spectral broadening compared to the uncoated waveguide, achieving a broadening factor of up to ~3.4 for a device with 2 layers of GO. By fitting the experimental results with theory, we obtain an improvement in the waveguide nonlinear parameter by a factor of up to 18.4 and a Kerr coefficient (n2) of GO that is about 5 orders of magnitude higher than Si3N4. Finally, we provide a theoretical analysis for the influence of GO film length, coating position, and its saturable absorption on the SPM performance. These results verify the effectiveness of on-chip integrating 2D GO films to enhance the nonlinear optical performance of Si3N4 devices.