Open-source toolbox for photographic characterization of optical propagation

Area of Science:

• Optics and Photonics
• Materials Science
• Integrated Photonics

Background:

• Characterizing optical propagation in waveguides is crucial for integrated photonic devices.
• Traditional methods like cut-back measurements can be destructive and time-consuming.
• Developing non-destructive, accurate, and reproducible loss measurement techniques is essential.

Purpose of the Study:

• To present and validate an alternative method for optical propagation characterization in waveguides using scattered light imaging.
• To demonstrate the technique's applicability across a broad spectral range (450-980 nm).
• To assess the method's reproducibility and compare it with established techniques.

Main Methods:

• Utilizing scattered light imaging to analyze light propagation within waveguide structures.
• Employing a tunable laser for measurements on AlGaAs-on-insulator waveguides.
• Comparing results with traditional cut-back measurements for validation.
• Introducing an open-source toolbox for data processing and loss estimation.

Main Results:

• Achieved low propagation losses as low as 1.40 dB/cm in alumina spiral waveguides.
• Demonstrated high reproducibility on AlGaAs waveguides with a one-sigma uncertainty of 1.40 dB/cm (TE) and 2.23 dB/cm (TM).
• Validated the scattered light imaging technique against cut-back measurements.

Conclusions:

• Scattered light imaging offers a reliable and reproducible alternative for characterizing optical propagation losses in waveguides.
• The developed open-source toolbox facilitates accurate loss estimation, benefiting the integrated photonics community.
• This technique provides valuable insights for optimizing waveguide design and performance.