Numerical analysis of a grating embedded bidirectional integrated optical coupler pressure sensor

Area of Science:

• Photonics and Waveguide Optics
• Optical Sensing Technologies
• Numerical Modeling in Electromagnetics

Background:

• Bidirectional optical coupled waveguide structures are crucial for advanced photonic devices.
• Grating-based sensors offer high sensitivity but require precise analysis.
• Understanding strain effects is vital for robust sensor design.

Purpose of the Study:

• To numerically analyze a grating-embedded bidirectional optical coupled waveguide structure.
• To investigate the strain sensing characteristics of this novel structure.
• To determine the Bragg grating sensitivities for individual TE and TM modes.

Main Methods:

• A finite difference method (FDM) based scheme was developed to extract eigen modes.
• A three-point central finite difference scheme with specific boundary conditions was employed.
• Numerical simulations were performed using MATLAB with N=1000 mesh points.

Main Results:

• The study presents the first known numerical analysis of this specific waveguide structure.
• Higher-order TE and TM modes demonstrated improved strain sensitivity.
• The effective refractive index theory was utilized for analysis and implementation.

Conclusions:

• The proposed numerical method accurately estimates Bragg grating sensitivities for TE and TM modes.
• The findings highlight the potential of higher-order modes for enhanced sensing performance.
• This technique can be extended to analyze sensitivities to temperature, humidity, and vibration.