Low-power all-optical switch based on a graphene-buried polymer waveguide Mach-Zehnder interferometer.

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nanotechnology

Background:

• All-optical switches are crucial for high-speed optical communication networks.
• Existing all-optical switching technologies often face challenges with power consumption, insertion loss, and integration.
• Graphene's unique optoelectronic properties offer potential for novel photonic devices.

Purpose of the Study:

• To propose and experimentally demonstrate a low-power all-optical switch.
• To utilize graphene's photothermal effect for all-optical switching within a balanced Mach-Zehnder interferometer (MZI).
• To optimize pump absorption and minimize signal loss using orthogonal polarizations.

Main Methods:

• Fabrication of a polymer waveguide device with embedded graphene.
• Utilizing a balanced Mach-Zehnder interferometer (MZI) structure.
• Employing orthogonal polarizations for pump and signal light to control graphene absorption and signal loss.

Main Results:

• Achieved a pump absorption of 10.6 dB and a graphene-induced signal loss of 1.1 dB.
• Demonstrated all-optical switching with a low pump power of 6.0 mW and an extinction ratio of 36 dB.
• Observed fast switching times (1.0 ms rise, 2.7 ms fall) with weak temperature sensitivity.

Conclusions:

• The proposed graphene-buried MZI all-optical switch offers efficient, low-power operation.
• The device exhibits excellent switching performance and robustness to temperature variations.
• Potential applications in fiber-based and on-chip all-optical signal processing are highlighted.