Dual Reflective Ferrule Assembly for Expanded Beam Optical Coupling

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Solution Overview

Problem

Existing optical fiber connectors face challenges with high insertion and return losses, high manufacturing costs, and environmental sensitivity, particularly in dirty and high-vibration environments.

Innovation Solution

The development of an optical fiber ferrule assembly with integrated reflective surfaces that expand the light beam, allowing for low insertion and return losses, ease of use, high reliability, and low environmental sensitivity, while being fabricated at low cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional polished fiber end faces are used for connection, then manufacturing precision can be achieved, but insertion loss and return loss remain high due to reflection and misalignment

Engineering Contradiction:
Improveinsertion lossVSAvoidfiber alignment tolerance
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent transitions from direct end-face-to-end-face coupling in the longitudinal dimension to expanded beam coupling where the beam expands in the transverse dimension. By expanding the optical beam diameter beyond the fiber core diameter, the system tolerates larger misalignments in the longitudinal and transverse dimensions while maintaining low insertion loss and return loss.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the optical parameters by expanding the beam diameter and altering the propagation characteristics. The expanded beam has a larger diameter and different divergence angle compared to the original fiber mode, which allows for relaxed alignment tolerances and reduced sensitivity to manufacturing variations.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If lenses are added to expand the beam in existing connectors, then environmental sensitivity is reduced, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveenvironmental sensitivityVSAvoidconnector structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the beam expansion function directly into the ferrule structure itself. The ferrule is formed with an expanded beam output end that directly expands the optical beam without requiring separate lenses or additional optical components. This integration reduces device complexity while maintaining the environmental robustness of expanded beam coupling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the beam expansion function from separate optical components (lenses) and incorporates it directly into the ferrule geometry. By removing the need for discrete lenses and their associated mounting and alignment mechanisms, the overall device complexity is reduced while achieving the same environmental sensitivity benefits.

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of energy

If sub-micron precision assembly is implemented, then optical loss is reduced, but manufacturing cost and production time increase

Engineering Contradiction:
Improveoptical lossVSAvoidassembly speed
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The patent changes the critical parameters by expanding the beam diameter, which transforms the system from requiring sub-micron precision to tolerating larger misalignments. The expanded beam geometry inherently provides a larger coupling aperture, allowing for faster, less precise assembly processes while maintaining low optical loss.

Inventive Principle:
Principle #35Parameter changes

4Loss of energy

If fiber end faces are polished for precise alignment, then coupling efficiency is improved, but manufacturing cost and process complexity increase

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidferrule fabrication
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The patent merges the beam expansion function directly into the ferrule structure itself. The ferrule is formed with an expanded beam output end that directly expands the optical beam without requiring separate lenses or additional optical components. This integration reduces device complexity while maintaining the environmental robustness of expanded beam coupling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the beam expansion function from separate optical components (lenses) and incorporates it directly into the ferrule geometry. By removing the need for discrete lenses and their associated mounting and alignment mechanisms, the overall device complexity is reduced while achieving the same environmental sensitivity benefits.

Inventive Principle:
Principle #2Taking out (Extraction)

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

The ferrule assembly achieves low insertion and return losses, enhances reliability and ease of use, reduces environmental sensitivity, and lowers manufacturing costs, making it suitable for high-throughput production.

Implementation Method 1

an first reflective surface, located beyond the end face of the optical fiber, configured to bend light output from the optical fiber

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3500882B1Optical fiber connector ferrule assembly having dual reflective surfaces for beam expansion and expanded beam connector incorporating same
Publication Date: 2025.02.12 SENKO ADVANCED COMPONENTS INC
  • EP3500882B1 patent drawingFigure 1A~1B
  • EP3500882B1 patent drawingFigure 1C~2A
  • EP3500882B1 patent drawingFigure 2B~2C

AI summary

An expanded beam ferrule includes a first ferrule halve having first reflective surfaces and a second ferrule halve having second reflective surfaces, which together retain optical fibers. The pair of reflective surfaces output collimated light parallel to the mid-plane of the ferrule. An external sleeve aligns the external surface of two similar ferrules, with corresponding second reflective surfaces of the ferrules facing each other. Output light from an optical fiber held in one ferrule is bent twice by the pair of reflective surfaces, with beam divergence after the first bent, and collimation after the second bent. The collimated light is transmitted to the facing second reflective surface in a facing second ferrule aligned by the sleeve, which is subject to optical reshaping in reverse to that undertaken in the first ferrule, so as to converge and focus light to input to the optical fiber held in the other ferrule.