Multi-Fiber Optic Delay Lines for Interferometer Dispersion Control

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Solution Overview

Problem

Existing fiber optic interferometers using optical fiber stretchers face challenges with temperature-dependent differential dispersion effects, leading to measurement errors and high costs due to the need for precise calibration and reproducibility in physical parameter measurements.

Innovation Solution

The use of one or two optical fiber stretchers that simultaneously vary the length of multiple optical fibers wound together around their surface by the same amount, minimizing temperature-dependent dispersion effects and reducing the need for expensive optical components by ensuring consistent optical path length differences when light of the same wavelength is transmitted through them.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separate optical fiber stretchers are used for each interferometer arm, then independent optical path length control is achieved, but temperature-dependent differential dispersion errors occur and measurement precision deteriorates

Engineering Contradiction:

Improveindependent optical path length controlVSAvoidmeasurement precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent merges the optical path length control function into a single shared optical fiber stretcher that simultaneously controls multiple interferometer arms. By winding multiple optical fibers around the same stretcher device, the system ensures that all arms experience identical temperature-dependent dispersion effects, thereby eliminating differential dispersion errors while maintaining the ability to independently vary optical path lengths through differential winding configurations.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple separate optical fiber stretchers are used, then individual arm adjustment is possible, but device complexity and cost increase

Engineering Contradiction:

Improveindividual arm adjustmentVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal optical fiber stretcher that serves multiple interferometer arms simultaneously. This single multi-functional device can adjust the optical path length of multiple arms through different winding configurations, eliminating the need for multiple separate stretchers and reducing overall device complexity while maintaining individual arm adjustability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If separate optical fiber stretchers are used for each arm, then independent control is achieved, but the cost of optical components increases

Engineering Contradiction:

Improveindependent controlVSAvoidcost of optical components

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The patent combines multiple optical path control functions into a single optical fiber stretcher device, significantly reducing the number of expensive optical components required. By using one shared stretcher with multiple winding configurations instead of multiple separate stretchers, the system achieves independent control capability at a lower component cost.

Inventive Principle:

Principle #5Merging (Combining)

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 more precise and cost-effective method for measuring physical parameters by eliminating temperature-dependent dispersion errors and improving measurement reproducibility, while maintaining consistent optical path lengths across multiple fibers.

Implementation Method 1

a cylindrical piezo-electric (PZT) actuator... when an electrical voltage is applied to the cylindrical PZT actuator to cause the diameter of the cylindrical PZT actuator to change

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

minimizing temperature-dependent dispersion effects... ensuring consistent optical path length differences when light of the same wavelength is transmitted through them

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10006754B2Associated interferometers using multi-fiber optic delay lines

Publication Date: 2018.06.26 LUMETRICS

AI summary

An interferometer apparatus which include two or more coupled fiber optic Michelson interferometers using fiber optic stretches which stretch two or more optical fibers wound around the perimeter of the optical fiber stretchers by the same amount is disclosed. Preferably a pair of reference and sample fiber optic stretches are utilized which run in a push-pull mode of operation. When one of the interferometers is a coherent light interferometer it can be used as a reference distance scale for all of the remaining low coherence light interferometer. A method for measuring a physical property of a device under test is also disclosed using the apparatus of the present invention.