Coupling-Controlled Photonic Topological Ring Array

Area of Science:

• Photonics
• Condensed Matter Physics
• Optical Engineering

Background:

• Photonic topological insulators offer robust light propagation by utilizing boundary states, mitigating issues from structural imperfections.
• Coupled resonator optical waveguides (CROWs) are effective platforms for realizing photonic topological insulators due to their distinct topological phases and band structures.

Purpose of the Study:

• To design and experimentally validate a CROW array capable of dynamically altering its topological phase.
• To demonstrate control over light propagation by manipulating the boundary between topological and trivial regions within the CROW array.

Main Methods:

• Fabrication of a coupled resonator optical waveguide (CROW) array.
• Experimental validation of tunable topological phase transitions by adjusting inter-resonator coupling strength.
• Demonstration of light guiding along the engineered boundary between topological and trivial insulator regions.

Main Results:

• The CROW array successfully exhibited tunable topological phases.
• Light was guided along the boundary between the topological and trivial regions, demonstrating defect-immune propagation.
• Control over the optical path was achieved by altering the shape of the topological insulator region.

Conclusions:

• The developed CROW-based photonic topological insulator provides a robust method for controlling light propagation.
• This tunable system shows potential for practical applications in optical switches, dynamic light steering, sensing, and computing.