Sensitivity enhancement in swept-source optical coherence tomography by parametric balanced detector and amplifier

Area of Science:

• Biomedical Optics
• Optical Engineering
• Signal Processing

Background:

• Swept-source optical coherence tomography (SS-OCT) is a crucial imaging technique.
• Enhancing sensitivity in SS-OCT is vital for deeper tissue penetration and improved image quality.
• Existing methods face limitations in achieving substantial sensitivity improvements.

Purpose of the Study:

• To propose and experimentally validate a novel sensitivity enhancement method for SS-OCT.
• To integrate an all-fiber optical parametric amplifier (FOPA) and a parametric balanced detector (BD) into an SS-OCT system.
• To quantify the sensitivity improvements achieved by the proposed method.

Main Methods:

• Implemented a sensitivity enhancement strategy using an all-fiber optical parametric amplifier (FOPA).
• Developed a parametric balanced detector (BD) by combining signal and phase-conjugated idler bands generated via FOPA.
• Superimposed the signal and idler bands at a photodetector for interference-based signal detection.
• Conducted experimental validation on SS-OCT systems and performed bio-sample imaging on loach eyes.

Main Results:

• Achieved over 9 dB sensitivity improvement in SS-OCT with FOPA.
• Demonstrated more than 12 dB sensitivity improvement in SS-OCT with the parametric BD.
• Observed significant sensitivity enhancements across a spectral bandwidth exceeding 76 nm.
• Bio-sample imaging confirmed the practical utility and effectiveness of the proposed method.

Conclusions:

• The integration of FOPA and parametric BD offers a significant sensitivity boost for SS-OCT systems.
• The proposed method effectively enhances interference-based signal detection in SS-OCT.
• This advancement holds potential for improved diagnostic capabilities in optical coherence tomography applications.