Polarization Maintaining Fiber Reference Arm OCT System
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Solution Overview
Problem
Conventional polarization sensitive optical coherence tomography (OCT) systems require bulky and costly polarization controllers to maintain equalized optical field intensities in orthogonal detection channels, due to the uncontrolled polarization state of single mode fibers, and polarization maintaining fibers introduce additional issues like high cost, tight angular tolerances, and crosstalk.
Innovation Solution
The integration of both polarization maintaining and single mode optical fibers in the OCT system, where polarization maintaining fibers are used in the reference arm to ensure equalized intensities without the need for external controllers, while single mode fibers are used where polarization state is not critical, reducing costs and improving connector tolerances and minimizing crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarization maintaining fiber is used in the reference arm to maintain equalized optical field intensities, then polarization state control is improved, but system cost increases and angular tolerances on splices/connectors become tighter
Solution Approach 1:
The patent applies local quality by using polarization maintaining fiber only in the reference arm where polarization state control is critical, while using standard single mode fiber in the sample arm and detection pathways where polarization control is not critical. This localized application of polarization maintaining fiber achieves the necessary polarization stability without incurring the full cost and manufacturing complexity penalties of using it throughout the entire system.
2Manufacturing precision
If polarization controller is used to adjust polarization state for equalized intensities, then detection channel balance is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the polarization controller component from the system by using polarization maintaining fiber in the reference arm. The polarization maintaining fiber inherently maintains the polarization state without requiring external control devices, thereby removing the complexity and cost associated with polarization controllers while still achieving equalized intensities in the detection channels.
Solution Approach 2:
The polarization maintaining fiber serves itself by inherently maintaining the polarization state of light propagating through it. This self-service property eliminates the need for external polarization control mechanisms, as the fiber automatically maintains the required polarization state without additional components or active control systems.
3Reliability
If polarization maintaining fiber is used throughout the system, then polarization state is maintained, but crosstalk between polarization modes occurs and cost increases
Solution Approach 1:
The patent applies local quality by restricting polarization maintaining fiber to only those portions of the system where polarization state maintenance is critical (the reference arm), while using standard single mode fiber in other portions where polarization control is not critical. This approach maintains polarization state where needed while avoiding the crosstalk and cost penalties of using polarization maintaining fiber throughout the entire system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration eliminates the need for polarization controllers, reduces system costs, increases angular tolerances, and minimizes crosstalk between polarization modes, providing stable and cost-effective polarization sensitive OCT imaging.
Implementation Method 1
Polarization maintaining optical fiber is an option that maintains the polarization state of light as it propagates in the fiber
Implementation Method 2
The light reflects from both the sample and the reference arms and is recombined to make in situ tomographic images
Data Source
AI summary
The invention generally relates to a polarization sensitive optical coherence tomography (OCT) system that includes both polarization maintaining and single mode optical fiber and methods of use thereof. Generally, OCT systems of the invention have a light source and a differential path interferometer that includes a sample arm and a reference arm. A splitter is used to split light from the light source to the sample arm and the reference arm. Reflected light from the sample arm and the reference arm is recombined at a detector. The polarization maintaining fiber is used in the reference arm to ensure that optical field intensity is equalized between two orthogonal detection channels of the OCT system.