Characterization of an imaging multimode optical fiber using a digital micro-mirror device based single-beam system

Area of Science:

• Optical Physics
• Image Processing
• Metrology

Background:

• Characterizing multimode fiber (MMF) imaging systems typically requires a reference beam, adding complexity and cost.
• High-speed spatial light modulation is crucial for efficient system characterization.
• Retrieving phase information from intensity-only measurements is a significant challenge in optical imaging.

Purpose of the Study:

• To develop and experimentally validate a reference-free method for characterizing single multimode fiber imaging systems.
• To enable high-speed spatial light modulation for improved system analysis.
• To retrieve the phase of the output optical field and the fiber's transmission matrix.

Main Methods:

• Utilizing a digital micro-mirror device (DMD) for high-speed binary amplitude modulation.
• Recording intensity-only images with a camera.
• Applying a Bayesian inference-based algorithm to reconstruct phase and transmission matrix.
• Employing singular value decomposition (SVD) for data analysis.

Main Results:

• Successfully retrieved the phase of the output optical field and the fiber transmission matrix without a reference beam.
• Validated the transmission matrix through prediction accuracy, transmission imaging, and focus generation.
• Demonstrated extraction of mode count and eigenchannel information from the transmission matrix via SVD.

Conclusions:

• The developed experimental approach offers a robust and efficient method for characterizing multimode fiber imaging systems.
• This reference-free technique simplifies system complexity and reduces cost.
• The findings pave the way for compact and affordable single multimode fiber imaging solutions for demanding applications.