Angled Optical Fiber Cleaving with Slanted Blade

Solution Overview

Problem

Existing methods for cleaving optical fibers to create angled ends for splicing often result in significant glass protrusion, leading to increased insertion loss and back-reflection, which are difficult to control and require precise orientation of the fiber ends.

Innovation Solution

A method involving a slanted blade that introduces internal stresses by bending and scratching the fiber at an angle between 18° to 45° relative to the fiber axis, reducing the glass protrusion and allowing for closer approach of fiber cores without the need for precise orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cleaving methods (twisting or perpendicular scratching) are used to create angled fiber ends, then the fiber ends can be joined for splicing, but significant glass protrusion occurs leading to increased insertion loss and back-reflection

Engineering Contradiction:

Improveoptical splice qualityVSAvoidinsertion loss and back-reflection

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention changes the blade orientation parameter from perpendicular (0°) to slanted (15°-45°) relative to the fiber axis. This parameter change fundamentally alters the stress distribution during cleaving, producing an angled end face with reduced glass protrusion. The slanted blade creates a controlled fracture pattern that eliminates the nose formation while maintaining the desired cleave angle for low back-reflection.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces asymmetry in the cleaving process by slanting the blade at an angle to the fiber axis rather than maintaining symmetry with perpendicular scratching. This asymmetric approach creates a controlled asymmetric fracture pattern that produces the desired angled end face geometry, reducing glass protrusion while maintaining structural integrity.

Inventive Principle:

Principle #4Asymmetry

2Object-affected harmful factors

If angled cleaves are created by twisting the fiber prior to cleaving, then the end face is angled for reduced back-reflection, but a large nose of glass projects beyond the core hindering close approach of fiber cores

Engineering Contradiction:

Improveback-reflectionVSAvoidglass protrusion or nose

Core Design Contradiction:

Object-affected harmful factorsVSShape

Solution Approach 1:

The invention changes the blade orientation parameter from perpendicular to slanted (15°-45°) relative to the fiber axis. This parameter change fundamentally alters the stress distribution during cleaving, producing an angled end face with reduced glass protrusion. The slanted blade creates a controlled fracture pattern that eliminates the nose formation while maintaining the desired cleave angle for low back-reflection.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The slanted blade technique effectively extracts or removes the harmful glass nose protrusion that normally forms with conventional perpendicular scratching. By changing the blade angle, the fracture propagates in a way that leaves a clean angled surface without the excessive glass projection, thereby taking out the problematic element that hinders fiber core approach.

Inventive Principle:

Principle #2Taking out (Extraction)

3Length of moving object

If perpendicularly terminated cleaved end faces are used, then the closest possible approach between fiber ends is achieved, but substantial back-reflection (up to 4% of incident light) is transmitted back down the fiber

Engineering Contradiction:

Improvegap between fiber endsVSAvoidback-reflection

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The invention introduces asymmetry in the cleaving process by slanting the blade at an angle to the fiber axis rather than maintaining symmetry with perpendicular scratching. This asymmetric approach creates a controlled asymmetric fracture pattern that produces the desired angled end face geometry, reducing glass protrusion while maintaining structural integrity.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The invention changes the blade orientation parameter from perpendicular (0°) to slanted (15°-45°) relative to the fiber axis. This parameter change fundamentally alters the stress distribution during cleaving, producing an angled end face with reduced glass protrusion. The slanted blade creates a controlled fracture pattern that eliminates the nose formation while maintaining the desired cleave angle for low back-reflection.

Inventive Principle:

Principle #35Parameter changes

4Object-affected harmful factors

If index matching gel is used to fill the gap between fiber ends, then reflections are suppressed over a limited temperature range, but the solution is only effective under specific conditions

Engineering Contradiction:

ImprovereflectionsVSAvoidtemperature range effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The angled cleaving method extracts or eliminates the need for index matching gel by addressing the root cause of reflections through geometric design. By creating an angled end face (8° typically), reflected light is directed away from the fiber core, making the system effective without temperature-sensitive materials.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the harmful effect of reflection into a beneficial directional characteristic. By angling the end face, the reflection is not eliminated but redirected away from the fiber core, transforming a harmful back-reflection into a useful forward-directed reflection that does not interfere with signal transmission.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach reduces the glass protrusion beyond the fiber core, minimizing insertion loss and back-reflection, enabling low-loss optical splices with uncontrolled fiber orientation, suitable for field termination and connector applications.

Implementation Method 1

A method is described of cleaving one or more optical fiber at an angle to the optic axis in which a sharp blade is used to scratch the fiber or fibers and so introduce internal stresses

Methodology Applied

Scientific EffectStress concentration:

Implementation Method 2

scratching the fiber or fibers with the sharp blade to create a non-perpendicular cleave having a controlled shape in the region of the scratch

Methodology Applied

Scientific EffectFracture mechanics: Fracture Mechanics

Data Source

PatentUS9933571B2Profiling of cleaved angled end faces of optical fiber(s)

Publication Date: 2018.04.03 OXFORD FIBER

AI summary

A method for cleaving one or more optical fiber(s) at an angle to the optic axis is provided and includes clamping the optical fiber(s) with its coating stripped to expose its distal end. An axial force and/or a bending force is applied to the optical fiber to create internal stresses in the fiber. A sharp blade is provided in an orientation such the blade edge is perpendicular to the optical fiber. The blade is further orientated such that a plane bisecting the blade angle formed between two polished surfaces of the blade is slanted relative to the longitudinal axis of the fiber. The at least one optical fiber is scratched with the sharp blade to create a non-perpendicular cleave having a controlled shape in the region of the scratch. A method of splicing the fibers and a tool for cleaving the fibers are also provided.