MPO Loopback Fiber Attenuator Using Angled Ferrules

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Solution Overview

Problem

Fiber attenuators based on loopback assemblies, particularly those using doped fibers, are expensive and suffer from mode-dependent attenuation issues in multimode fiber applications, making them unsuitable for cost-effective and stable testing across both multimode and single-mode fibers.

Innovation Solution

The use of an MPO loopback assembly with angled ferrules and non-angled ferrules forming air gaps, combined with anti-reflection coating and controlled polishing angles, to manage light transmission and reflection losses, allowing for adjustable insertion and reflection losses without the need for expensive doped fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If doped fiber is used to create loopback assembly, then attenuation loss is achieved, but cost increases significantly

Engineering Contradiction:

Improveattenuation lossVSAvoidcost

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent replaces expensive doped fiber with standard optical fiber combined with mechanical bending elements. The loopback assembly uses conventional fiber that can be bent at controlled radii to achieve the required attenuation, eliminating the need for costly doped fiber while maintaining the attenuation function.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent achieves attenuation by changing physical parameters of the fiber path - specifically the bending radius and number of bends. By controlling the bend radius (R1, R2) and the geometry of the loopback path, the desired attenuation is achieved without modifying the fiber material composition, thus avoiding the cost of doped fiber.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If doped fiber is used for loopback assembly, then attenuation is provided, but mode-dependent attenuation occurs in multimode fiber

Engineering Contradiction:

ImproveattenuationVSAvoidmode-dependent attenuation stability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent replaces the optical mechanism of doped fiber attenuation with a mechanical bending mechanism. By controlling the physical bend radius and geometry of the fiber path, attenuation is achieved through macro-bending losses rather than material absorption, thereby eliminating mode-dependent attenuation issues inherent in doped multimode fiber.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If loopback assembly is designed for single-mode fiber, then single-mode testing is achieved, but compatibility with multimode fiber is lost

Engineering Contradiction:

Improvefiber type compatibilityVSAvoidtesting performance consistency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent designs a universal loopback assembly that works with both single-mode and multimode fibers using the same basic structure. The assembly uses standard connectors and bending geometry that are effective for both fiber types, allowing a single design to serve multiple fiber type requirements without sacrificing performance consistency.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 provides a cost-effective solution for simulating fiber attenuation, ensuring consistent performance across different fiber modes by controlling light losses through air gaps and coatings, thereby stabilizing testing results and reducing the dependency on expensive doped fibers.

Implementation Method 1

light exits from a fiber core of the non-angled ferrule of the MPO connector, expands as it travels across the air gap, and enters an angled ferrule of the MPO loopback assembly

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

light exits from a fiber core of the non-angled ferrule of the MPO connector, expands as it travels across the air gap

Methodology Applied

Scientific EffectGeometric expansion:

Data Source

PatentUS9482823B1Fiber attenuator based on MPO loopback assembly having angled ferrules

Publication Date: 2016.11.01 ALLIAN FIBER OPTIC PROD INC

AI summary

An apparatus comprises a first array of angled ferrules and a second array of angled ferrules, a plurality of angled fibers, wherein first ends of the plurality of angled fibers are held in the first array of angled ferrules and second ends of the plurality of angled fibers are held in the second array of angled ferrules, a first array of non-angled ferrules and a second array of non-angled ferrules, a first plurality of non-angled fibers held in the first array of non-angled ferrules, a second plurality of non-angled fibers held in the second array of non-angled ferrules, wherein the first array of angled ferrules is aligned and connected with the first array of non-angled ferrules and the second array of angled ferrules is aligned and connected with the second array of non-angled ferrules.