Photo-Thermal Tuning of Graphene Oxide Coated Integrated Optical Waveguides

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Two-dimensional (2D) materials like graphene oxide (GO) offer unique properties for integrated photonics.
• Photo-thermal tuning (PTT) is a method to modify material properties using light and heat.

Purpose of the Study:

• To experimentally investigate the power-sensitive photo-thermal tuning (PTT) of 2D graphene oxide (GO) films on silicon nitride (SiN) optical waveguides.
• To determine the light power thresholds for reversible and permanent GO reduction.
• To understand the influence of GO layer number and laser type on PTT.

Main Methods:

• Fabrication of SiN optical waveguides with one and two layers of GO.
• Experimental measurement of light power thresholds for GO reduction using continuous-wave and pulsed lasers.
• Characterization of reduced GO using Raman spectroscopy.

Main Results:

• Identified power thresholds for reversible and permanent GO reduction: ~20/22 dBm (1 layer) and ~13/18 dBm (2 layers).
• Observed inhomogeneous GO reduction along the waveguide direction.
• Confirmed PTT dependence on average input power, not laser type (CW vs. pulsed).

Conclusions:

• Demonstrated power-sensitive PTT of 2D GO films on integrated optical waveguides.
• Established critical power thresholds for GO reduction, enabling control over its properties.
• Highlighted the potential of GO for hybrid integrated photonic devices.