3x3 Mach-Zehnder interferometer with unbalanced differential detection for full-range swept-source optical coherence...

Area of Science:

• Optical Engineering
• Biomedical Imaging
• Interferometry

Background:

• Swept-source optical coherence tomography (SS-OCT) is limited by imaging depth.
• Complex conjugate artifacts degrade SS-OCT image quality.
• Existing detection methods have limitations in artifact suppression and signal-to-noise ratio.

Purpose of the Study:

• To develop and validate a novel unbalanced differential detection method for 3x3 fiber coupler-based quadrature interferometry.
• To enhance the effective imaging depth in SS-OCT by suppressing complex conjugate artifacts.
• To improve the signal-to-noise ratio (SNR) compared to conventional detection techniques.

Main Methods:

• Theoretical and experimental investigation of a 3x3 Mach-Zehnder interferometer.
• Implementation of a new unbalanced differential optical detection scheme.
• Characterization of complex conjugate artifact suppression and SNR using SS-OCT.

Main Results:

• Demonstrated simultaneous access to complementary phase components of the interferometric signal without trigonometric calculations.
• Achieved 27 dB complex conjugate artifact suppression in SS-OCT.
• Showed an SNR improvement of at least 4 dB compared to balanced detection due to better optical power utilization.

Conclusions:

• The proposed unbalanced differential detection method effectively suppresses complex conjugate artifacts in SS-OCT.
• This technique enhances imaging depth and improves SNR, offering a significant advancement over balanced detection.
• The method provides a more efficient way to extract phase information for improved OCT imaging.