Insights into complex Berenger modes: a view from the weighted optical path distance perspective

Area of Science:

• Computational electromagnetics
• Optical engineering
• Semiconductor device physics

Background:

• Accurate computation of higher-order modes is essential for designing advanced optical devices.
• Existing methods for Berenger mode computation can be complex and computationally intensive.
• Understanding mode behavior in substrate and cladding is critical for device performance.

Purpose of the Study:

• To develop a simple and efficient approach for higher-order Berenger mode computation.
• To establish the physical mapping between radiation modes and complex Berenger modes.
• To validate the proposed method's robustness, efficiency, and accuracy.

Main Methods:

• Establishing a physical mapping between radiation modes and complex Berenger modes.
• Theoretically proving mode convergence in substrate and cladding.
• Implementing the model by adjusting perfectly matched layer parameters.
• Utilizing a germanium (Ge) photodetector for evaluation.

Main Results:

• Demonstrated that higher-order substrate and cladding Berenger modes converge to complex modes with a shared phase angle.
• The model is explained by weighted optical path distance in cladding and substrate.
• The method shows robustness, efficiency, and accuracy in evaluating a germanium photodetector.

Conclusions:

• The proposed method offers a simplified and efficient way to compute higher-order Berenger modes.
• The findings provide a theoretical basis for understanding mode behavior in optical structures.
• The validated approach has practical implications for optical device design and simulation.