2D optical confinement in an etchless stratified trench waveguide.

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Traditional ridge waveguides often suffer from scattering losses due to etched sidewall roughness.
• Achieving efficient two-dimensional (2D) optical confinement typically requires complex fabrication processes.

Purpose of the Study:

• To introduce novel trapezoidal and rectangular stratified trench optical waveguide designs.
• To demonstrate low-loss 2D confinement of guided optical modes in polymer thin films.
• To eliminate the need for etching the waveguide core, thereby reducing scattering losses.

Main Methods:

• Utilizing geometrical bends within a thin film core to achieve 2D light confinement.
• Forming continuous polymer thin film layers in a trench mold.
• Employing finite-difference eigenmode simulations to analyze waveguide performance.

Main Results:

• Demonstrated 2D confinement of optical modes without core thickness variation.
• Achieved low intrinsic leakage loss (<0.15 dB/cm) through optimized waveguide geometry.
• Successfully obviated the need for etching the waveguide core, preventing sidewall scattering loss.

Conclusions:

• Stratified trench waveguides offer a viable alternative to traditional designs, minimizing propagation loss.
• The proposed design enables efficient light confinement and reduces fabrication-induced scattering.
• Further investigation into design considerations and trade-offs for propagation loss and confinement is warranted.