Design and analysis of 2D one-way splitter waveguide based on topological photonics

Area of Science:

• Photonics
• Condensed Matter Physics
• Electromagnetism

Background:

• Photonic topological insulators offer robust wave propagation due to protected edge states.
• Waveguide splitters are crucial components in photonic integrated circuits.
• Backscattering in conventional waveguides limits transmission efficiency.

Purpose of the Study:

• To design a high-efficiency waveguide splitter utilizing photonic topological insulator properties.
• To investigate the creation and characteristics of resonating modes within the designed structure.
• To achieve near-perfect transmission in waveguide outputs.

Main Methods:

• Utilized photonic topological insulators to create a 2D waveguide system.
• Introduced defects by eliminating rows and columns of magneto-optical rods to engineer edge modes.
• Calculated transmission at outputs to identify resonating modes and their properties.
• Employed the transmission line resonator model for semi-analytical validation.

Main Results:

• Achieved nearly 100% transmission in waveguide outputs due to robust edge states and suppressed backscattering.
• Identified specific defect configurations that create localized resonating modes.
• Discovered a promising resonating mode with a high quality factor (Q = 1.02 × 10^6) at 8.23 GHz when two rods and two columns were removed.
• Observed near-zero transmission at the resonating frequency to the outputs, indicating strong mode localization.

Conclusions:

• The proposed photonic topological insulator waveguide splitter design demonstrates exceptional efficiency.
• Defect engineering provides a method to control and utilize resonating modes within topological photonic structures.
• The findings are validated by a semi-analytical transmission line resonator model, confirming the design's potential for practical applications.