Silicon Optical Bench for OCT Probe Alignment

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Solution Overview

Problem

Current optical probes for OCT imaging, particularly in medical applications, face challenges in efficiently coupling and aligning optical fibers with reflecting surfaces, leading to suboptimal optical performance and mechanical stability during scanning of biological tissues.

Innovation Solution

The optical probe design incorporates a silicon optical bench with a fiber groove system that securely holds the optical fiber termination, featuring a blind groove with a reflecting surface and an anamorphic lens structure, which provides precise alignment and strain relief, enhancing optical coupling and mechanical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional GRIN lens and fold mirror arrangements are used in optical probes, then the probe can transmit and receive optical signals, but the optical coupling between the fiber termination and reflecting surface is imprecise and mechanically unstable during scanning

Engineering Contradiction:
Improveoptical coupling precisionVSAvoidmechanical stability during scanning
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The optical bench is divided into functionally distinct regions: a fiber groove section for securing the optical fiber, a blind groove section for housing the reflecting surface, and a lens section for beam shaping. This segmentation allows each component to be optimized independently for its specific function while maintaining precise relative positioning through the rigid bench structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary optical bench structure that mediates between the optical fiber termination and the reflecting surface. This bench provides a rigid mounting platform with precision features (fiber grooves, blind grooves, and alignment markers) that ensure stable and precise optical coupling, eliminating the need for direct or loose coupling arrangements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the optical fiber is directly coupled to the reflecting surface without a bench structure, then the device complexity is reduced, but the alignment precision and strain relief are insufficient

Engineering Contradiction:
Improvealignment precisionVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated optical bench structure: fiber securing (via fiber grooves), reflecting surface mounting (via blind grooves), and optical path definition (via lens sections) are combined in one component. This integration achieves high alignment precision while minimizing the number of separate parts, thereby reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical bench serves multiple functions simultaneously: it acts as a mounting structure for the fiber and reflecting surface, provides precise alignment through grooves and markers, offers strain relief for the fiber, and defines the optical beam path. This multi-functionality eliminates the need for separate components for each function, reducing complexity while maintaining precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If a robust bench structure is used to hold the optical fiber and reflecting surface, then mechanical stability is improved, but the ease of manufacture decreases

Engineering Contradiction:
Improvemechanical stabilityVSAvoidfabrication ease
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent employs anisotropic etching of silicon wafers to create the optical bench structure. By controlling the etching parameters (direction, depth, and pattern), the process produces precise fiber grooves, blind grooves, and alignment features directly in the bench material. This parameter-controlled manufacturing approach achieves high mechanical stability while maintaining ease of fabrication through standardized semiconductor processing techniques.

Inventive Principle:
Principle #35Parameter changes

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 design improves the optical performance by ensuring precise alignment and strain relief, allowing for high-resolution imaging and stable operation during the scanning of biological tissues, such as in coronary arteries.

Implementation Method 1

a reflecting surface that optically couples an endface of the optical fiber termination to a lateral side of the optical bench

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

an anamorphic lens structure, which provides precise alignment and strain relief, enhancing optical coupling

Methodology Applied
Scientific EffectRefraction and Focusing: Lens

Data Source

PatentEP2528495B1Silicon optical bench oct probe for medical imaging
Publication Date: 2018.03.28 AXSUN TECHNOLOGIES INC
  • EP2528495B1 patent drawingFigure 1~2
  • EP2528495B1 patent drawingFigure 3~4
  • EP2528495B1 patent drawingFigure 5

AI summary

An optical probe for emitting and/or receiving light within a body comprises an optical fiber that transmits and/or receives an optical signal, a silicon optical bench including a fiber groove running longitudinally that holds an optical fiber termination of the optical fiber and a reflecting surface that optically couples an endface of the optical fiber termination to a lateral side of the optical bench. The fiber groove is fabricated using silicon anisotropic etching techniques. Some examples use a housing around the optical bench that is fabricated using LIGA or other electroforming technology. A method for forming lens structure is also described that comprises forming a refractive lens in a first layer of a composite wafer material, such as SOI (silicon on insulator) wafers and forming an optical port through a backside of the composite wafer material along an optical axis of the refractive lens.