Optical Fiber Termination Using Scattered Light Imaging

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Solution Overview

Problem

Mechanical splicing of optical fibers often results in significant signal loss and light leakage due to poor alignment and mismatched optical properties, leading to insertion loss values that exceed specified limits, which can compromise data rate and bit error rate performance.

Innovation Solution

An optical fiber termination system that includes a reference fiber, a light source, a digital camera sensor, and a processor to capture and analyze scattered light patterns, allowing for real-time estimation of insertion loss and ensuring proper alignment and optical matching between the field fiber and the stub fiber before mechanical splicing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mechanical splicing is used to join optical fibers, then the operation is simple and quick, but significant signal loss and light leakage occur due to poor alignment

Engineering Contradiction:
Improveease of mechanical splicingVSAvoidsignal loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by capturing a reference image of the scattered light pattern from the optical fiber end face before splicing. This reference image is stored and later used to compare against the post-splicing image, enabling detection of alignment quality and estimation of insertion loss before the fiber is permanently spliced.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by comparing the scattered light pattern in the post-splicing image with the reference image using image processing algorithms. This comparison provides feedback on the quality of the splice, including alignment accuracy and estimated insertion loss, allowing operators to assess splice quality in real-time.

Inventive Principle:
Principle #23Feedback

2Productivity

If mechanical splicing is used without alignment verification, then the process is fast, but insertion loss exceeds specified limits compromising data rate

Engineering Contradiction:
Improvesplicing speedVSAvoidalignment precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies self-service by using the optical fiber itself as the light source. The fiber transmits light from a remote source, and the scattered light pattern captured from the fiber end face provides self-diagnostic information about the fiber's optical properties and alignment quality without requiring external testing equipment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical alignment verification methods with an optical-based imaging system. Instead of using mechanical gauges or visual inspection, the system uses a digital camera to capture scattered light patterns and processes these images to determine alignment quality and estimate insertion loss.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of energy

If fusion splicing apparatus is used to create high performance joints, then signal loss is minimized, but the apparatus is bulky, expensive and fragile

Engineering Contradiction:
Improvesignal lossVSAvoidapparatus complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent uses copying by creating a digital reference copy of the scattered light pattern from the optical fiber. This reference image serves as a template for comparing post-splicing images, eliminating the need for physical reference standards or complex measurement apparatus while maintaining measurement accuracy.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent changes the parameter being measured from direct optical power measurement to analysis of scattered light spatial distribution. By capturing and analyzing the spatial pattern of scattered light rather than measuring power directly, the system can estimate insertion loss and alignment quality using simple imaging equipment instead of expensive power meters and alignment tools.

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

The system effectively reduces light leakage and reflection, ensuring that the insertion loss remains within acceptable limits, thereby enhancing channel performance and reducing costs associated with poor-quality splice joints.

Implementation Method 1

capture and analyze scattered light patterns

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP3704462B1Optical fiber termination method using a reference source
Publication Date: 2022.04.06 PANDUIT CORP
  • EP3704462B1 patent drawingFigure 1
  • EP3704462B1 patent drawingFigure 2
  • EP3704462B1 patent drawingFigure 3

AI summary

Examples disclosed herein illustrate systems and methods to determine and evaluate the quality of mechanical splices of optical fibers using insertion loss estimation. In at least some of the disclosed systems and methods, an optical fiber termination system (100) may include a reference fiber (301) coupling a light source (201) and a stub fiber (101) of a fiber optic connector (109), a digital camera sensor (205) and lens (204) to capture images of scattered light emanating from a portion of the fiber optic connector (109) and a portion of the reference fiber (301) both in a field of view (FOV) of the digital camera sensor (205), and a processor (206). The processor (206) may analyze digital images of scatter light emitted from at least a portion of the fiber optic connector (109) and the reference fiber (301) to estimate insertion loss at the fiber optic connector (109).