Optical Connector Non-Orthogonal Incidence Plane

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Solution Overview

Problem

Optical connectors with GRIN lenses and waveguides suffer from deteriorated optical characteristics due to reflected return light at the incidence/emission planes, particularly when the optical axes are orthogonal, leading to connection issues and reduced performance.

Innovation Solution

The optical connector design includes a waveguide member with a first optical axis and a GRIN lens with a second optical axis offset relative to the waveguide member's axis, ensuring the incidence/emission plane is not orthogonal to the optical beam axes, combined with a manufacturing method that involves specific steps for assembling and fixing the GRIN lenses and waveguide members to prevent orthogonal alignment and reduce return loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the incidence/emission plane is made orthogonal to the optical axes of optical fibers and GRIN lenses, then the结构简单性 (structural simplicity) is improved, but the optical characteristics deteriorate due to reflected return light connecting to the optical fiber

Engineering Contradiction:
Improvestructural simplicityVSAvoidoptical characteristics
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies asymmetry by intentionally making the incidence/emission plane non-orthogonal to the optical axes of the optical fibers and GRIN lenses. This asymmetric configuration prevents reflected return light from connecting back to the optical fiber, thereby improving optical characteristics while maintaining acceptable structural complexity

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the angular parameter of the incidence/emission plane relative to the optical axes. By adjusting this angle from orthogonal (90 degrees) to a non-orthogonal angle, the patent achieves both beam magnification and suppression of reflected return light connection to the optical fiber

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the GRIN lens is positioned with its optical axis offset from the waveguide optical axis, then the reflected return light connection is suppressed, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvereturn loss suppressionVSAvoidoptical axis alignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-positioning the GRIN lens with its optical axis offset from the waveguide optical axis during the assembly process. This pre-established offset configuration ensures that reflected return light is suppressed before the connector is put into service, while allowing for controlled manufacturing precision through standardized offset distances

Inventive Principle:
Principle #10Preliminary action

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 effectively suppresses the deterioration of optical characteristics by preventing reflected return light from connecting to the waveguide, achieving improved return loss and maintaining good optical performance, especially in single-mode transmission applications.

Implementation Method 1

a Graded Index (GRIN) lens is disposed at each of end portions of optical fibers in each of holding holes for the optical fibers at a ferrule, and optical connection is performed via a beam magnified at the GRIN lens

Methodology Applied
Scientific EffectGraded Index (GRIN) lens magnification: Lens

Implementation Method 2

reflected return light reflected at the incidence/emission plane of the end surface on one side and at the incidence/emission plane of the end surface of the optical connector on the other side is connected to the optical fiber

Methodology Applied
Scientific EffectOptical reflection: Reflection

Data Source

PatentEP2998770B1Optical connector and manufacturing method for optical connector
Publication Date: 2019.10.23 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP2998770B1 patent drawingFigure 1
  • EP2998770B1 patent drawingFigure 2
  • EP2998770B1 patent drawingFigure 3

AI summary

An optical connector 1 according to an embodiment includes a plurality of light incidence/emission portions 10 and a ferrule 20, and performs optical connection to an optical connector on the other side. Each of the plurality of light incidence/emission portions 10 includes a waveguide member 11 having a first optical axis L1, and a GRIN lens 12 including a second optical axis L2, and has one end 12a connected to an end portion 11a of the waveguide member 11 and the other end 12b provided with an incidence/emission plane 10a. The second optical axis L2 is offset relative to the first optical axis L1 at the end portion 11a of the waveguide member 11. The incidence/emission plane 10a is orthogonal to neither an optical axis of an optical beam emitted from the incidence/emission plane 10a nor an optical axis of an optical beam entering the incidence/emission plane 10a. The ferrule 20 includes guide portions 25, 26 to perform optical connection to the optical connector on the other side.