Polarization-Maintaining Fiber OCT Interferometer Assembly
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Solution Overview
Problem
Existing optical coherence tomography (OCT) systems face challenges with unpredictable polarization changes due to bending of hose cable packages, leading to signal-to-noise ratio loss and degraded image quality.
Innovation Solution
The solution involves dividing the interferometer into two parts, with a flexible optical fiber connection using polarization-maintaining light-guiding fibers connected in a cross-configuration to maintain polarization stability and avoid ghost artefacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional single-mode fibers are used to connect system parts, then the hose cable package can be flexible and movable, but unpredictable polarization changes occur leading to signal-to-noise ratio loss
Solution Approach 1:
The patent changes the optical parameter of the fiber by using polarization-maintaining fibers instead of conventional single-mode fibers. This parameter change ensures that the polarization state of light is preserved despite bending or movement of the hose cable package, thereby maintaining signal-to-noise ratio stability while retaining flexibility.
Solution Approach 2:
The patent employs a composite fiber structure combining polarization-maintaining fiber properties with flexible hose cable construction. This composite approach allows the cable package to be both mechanically flexible and optically stable, resolving the contradiction between ease of operation and reliability.
2Reliability
If polarization-maintaining fibers are used, then polarization stability is maintained during bending, but ghost artefacts occur due to birefringence
Solution Approach 1:
The patent extracts or removes the harmful birefringence effect by using a specific fiber configuration where the birefringence-induced ghost artefacts are eliminated while retaining the polarization-maintaining property. This is achieved through careful design of the fiber connection and orientation.
Solution Approach 2:
The patent converts the potentially harmful birefringence effect into a beneficial polarization-maintaining property by properly configuring the fiber axes. The birefringence that could cause ghost artefacts is instead harnessed to maintain stable polarization states, turning a harmful factor into a useful feature.
3Volume of moving object
If the interferometer is divided into two separate system parts, then the camera head can be compact and portable, but frequent polarization alignment is required
Solution Approach 1:
The patent changes the polarization sensitivity parameter of the system by using polarization-maintaining fibers throughout the divided interferometer system. This parameter change makes the system insensitive to polarization changes during movement, eliminating the need for frequent realignment and reducing time loss.
4Reliability
If polarization alignment is performed frequently, then signal-to-noise ratio is optimized, but productivity decreases due to time-consuming procedures
Solution Approach 1:
The patent implements a self-aligning system where the polarization-maintaining fiber configuration automatically preserves the polarization state without requiring manual intervention. The system serves itself by maintaining optimal polarization alignment through its inherent fiber properties, eliminating time-consuming realignment procedures and improving productivity.
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 ensures that the OCT system remains insensitive to fiber manipulation, maintaining stable polarization and reducing hardware costs and data volume, while achieving high image quality without the need for frequent polarization alignment.
Implementation Method 1
At least a first flexible light guide (3) is designed as a polarization-maintaining light guide which consists of two polarization-maintaining light-guiding fibers (3a, 3b), which are connected to each other
Implementation Method 2
Conventional light-guiding single-mode fibers (SMFs for short) only guide components of light rays oriented transversely to the direction of propagation
Implementation Method 3
A third partial beam, namely light reflected from the organic tissue, interferes with the second partial beam in an interferometer. Signals from the interference allow depth-resolved examination of the tissue
Implementation Method 4
light with a large bandwidth and a temporally short coherence length is usually divided into two partial beams in a beam splitter
Data Source
AI summary
The invention relates to an assembly comprising a interferometer for carrying out an optical coherence tomography, wherein the interferometer is divided into two spatially spaced-apart interferometer parts (1, 2), wherein the two interferometer parts (1, 2) can be moved related to one another and are optically connected to one another via flexible light guides (3, 4, 5), which bridge the spatial distance, wherein according to the invention, an assembly having an interferometer is provided, which is as unsusceptible as possible to the effects brought about by bending a tube cable packet and allows for an optimum signal-to-noise ratio or an optimum image quality of an OCT image, characterised in that at least one first flexible light guide (3) is designed as a polarisation-maintaining light guide consisting of two connected polarisation-maintaining light-guiding fibres (3a, 3b).