All-optical mode switching with a graphene-buried polymer waveguide directional coupler.

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nanotechnology

Background:

• All-optical switching is crucial for high-speed optical communication networks.
• Graphene's unique photothermal properties offer potential for novel optical devices.
• Waveguide-based devices are fundamental components in integrated photonics.

Purpose of the Study:

• To demonstrate all-optical mode switching in a graphene-buried polymer waveguide.
• To leverage the photothermal effect of graphene for efficient optical control.
• To investigate the performance of an asymmetric directional coupler for mode switching.

Main Methods:

• Fabrication of a graphene-buried polymer waveguide asymmetric directional coupler.
• Utilizing TE-polarized pump light and TM-polarized signal light to maximize pump absorption and minimize signal loss.
• Characterization of pump absorption, signal loss, extinction ratios, and switching times.

Main Results:

• Achieved a pump absorption of 3.4 dB at 980 nm and a low graphene-induced signal loss of 0.1 dB.
• Demonstrated spatial switching between fundamental and higher-order modes with extinction ratios exceeding 10 dB at 1580 nm.
• Observed switching times slightly less than 1 ms at a pump power of 36.6 mW.

Conclusions:

• Graphene-buried polymer waveguides enable efficient all-optical mode switching.
• The photothermal effect of graphene is a viable mechanism for low-power all-optical control.
• This technology opens new avenues for developing advanced integrated photonic devices.