Reducing bend-induced loss and crosstalk in a two-mode ridge waveguide by steplike thickness structuring

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Optical waveguides are crucial for integrated photonic circuits.
• Bending optical waveguides often introduces signal degradation like loss and inter-mode crosstalk.
• Minimizing these losses is essential for efficient optical signal transmission.

Purpose of the Study:

• To investigate a novel method for reducing bend-induced losses in optical waveguides.
• To develop an analytical model for optimizing waveguide structure in bent sections.
• To verify the effectiveness of the proposed technique through numerical simulations.

Main Methods:

• Two-step structuring of waveguide thickness in the bent section.
• Derivation of an analytical formula relating thickness change to waveguide geometry and bending radius.
• Numerical simulations using transformation optics formalism to assess loss and inter-mode crosstalk.

Main Results:

• Significant reduction in bend-related inter-mode crosstalk, excess loss, and pure bending loss.
• Validation of the analytical formula for predicting required thickness adjustments.
• Demonstrated improvement in performance parameters for TE00 and TE01 modes in a TiO2:SiO2 waveguide.

Conclusions:

• Two-step thickness structuring is an effective strategy for mitigating bend-induced losses in optical waveguides.
• The derived analytical formula provides a practical tool for designing optimized bent waveguides.
• This approach offers a significant advancement for integrated photonic device performance.