Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides

Area of Science:

• Optoelectronics
• Materials Science
• Waveguide Optics

Background:

• Interferometers are crucial optical devices.
• Polymer waveguides offer unique properties for optical sensing.
• Understanding waveguide parameters is key for device performance.

Purpose of the Study:

• To model and determine waveguide parameters for a broadband, polymer-based slab waveguide difference interferometer.
• To investigate the influence of waveguide properties on the output signal.
• To compare polymer waveguides with traditional materials like Si3N4.

Main Methods:

• Development of a theoretical model for the interferometer.
• Determination of waveguide parameters based on material dispersion.
• Analysis of the impact of waveguide layer thickness, propagation path length, and refractive index changes.
• Derivation of a relationship for signal shift based on refractive index changes.

Main Results:

• Waveguide layer thickness dictates the direction of maximum signal shifting.
• A derived relationship simplifies the description of the interferometer using a propagation constant.
• Polymer waveguides, despite low refractive index contrast, yield significant signal shifts.
• Signal shifts in polymer waveguides are comparable or superior to Si3N4 waveguides for certain thicknesses.

Conclusions:

• Polymer-based slab waveguide difference interferometers are viable for broadband applications.
• The presented model accurately describes the interferometer's behavior and parameter influence.
• Polymer waveguides present a promising alternative to Si3N4 for enhanced optical sensing performance.