Common Path Waveguides for Stable OCT Imaging
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Solution Overview
Problem
Conventional OCT systems face issues with differential fiber stretching between reference and sample arm waveguides, leading to image offset and the need for frequent recalibration during ophthalmic and microsurgical procedures.
Innovation Solution
The use of a cladding to couple the sample and reference arm waveguides together in the OCT system, ensuring that both fibers move equally if stretched, thereby maintaining calibration and preventing image offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate fiber-based waveguides are used for reference and sample arms in OCT systems, then flexibility and ease of operation are improved, but differential fiber stretching causes image offset and calibration instability
Solution Approach 1:
The patent merges the reference arm waveguide and sample arm waveguide into a single integrated photonic chip platform. Both waveguides are fabricated on the same chip substrate with fixed geometric paths, eliminating the differential stretching issues that occur with separate flexible fiber-based waveguides while maintaining the functional separation needed for OCT operation
Solution Approach 2:
The patent replaces the mechanical fiber-based waveguide system with an integrated photonic circuit system where light is guided through etched waveguide paths on a chip. This substitution eliminates the mechanical flexibility and associated stretching problems of fibers while providing fixed, stable optical paths for both reference and sample arms
2Ease of operation
If fiber-based waveguides are used in OCT systems, then ease of operation is improved, but frequent recalibration is required due to fiber stretching
Solution Approach 1:
The patent combines both reference and sample arm waveguides on a single integrated photonic chip, ensuring that any physical movement or deformation affects both optical paths equally. This eliminates differential path length changes that would otherwise require recalibration, thereby reducing recalibration time while maintaining operational ease
3Measurement precision
If high precision calibration is required for depth resolution, then image quality is improved, but the system becomes more sensitive to fiber stretching and requires frequent maintenance
Solution Approach 1:
The patent replaces the mechanical fiber-based waveguide system with an integrated photonic circuit where waveguides are etched directly into the chip substrate. This provides fixed, rigid optical paths that are immune to the stretching and deformation issues affecting flexible fibers, thereby maintaining high depth resolution without increased sensitivity to mechanical disturbances
Solution Approach 2:
The patent integrates both reference and sample arm waveguides on the same photonic chip platform with fixed geometric paths. This ensures that both optical paths experience identical environmental conditions and physical deformations, eliminating differential path length changes that would otherwise compromise depth resolution accuracy
Data Source
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AI summary
An OCT imaging system may include an OCT light source operable to emit an OCT light beam, and a beam splitter operable to split the OCT light beam into a sample beam, transferred to a sample arm waveguide, and a reference beam, transferred to a reference arm waveguide. The sample arm waveguide and the reference arm waveguide may be coupled together within a cladding, wherein the cladding improves a calibration of a generated OCT image by fixing axial movement of the sample arm and reference arm waveguides relative to one another. By routing long reference and sample arm waveguide fibers together in the OCT system using a sheath/cladding, OCT image offset due to asymmetrical fiber stretching can be minimized or eliminated.