Multicore Waveguide Interferometer for Nanometer Optical Thickness

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Solution Overview

Problem

Conventional interferometers are inadequate for measuring the optical thickness and adsorption of thin layers, particularly in deformable or liquid substances, and are not suitable for in-situ changes in small layers, limiting their application in miniaturized studies and other physical parameter measurements.

Innovation Solution

A waveguide interferometer with a multicore waveguide structure, where at least one core is activated with a chemically active substance that changes optical thickness or absorption in response to environmental factors, utilizing a dielectric section and a fan-in/fan-out element to enhance sensitivity and allow measurement of optical thickness and other physical parameters like temperature and strain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional interferometers are used to measure optical thickness, then measurement capability is provided, but measurement precision for nanometer-scale changes in thin layers is insufficient

Engineering Contradiction:
Improveoptical thickness measurement precisionVSAvoidlayer thickness
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent divides the measurement system into multiple interferometric paths using a multicore waveguide structure, where each core can independently measure optical thickness. This segmentation allows for enhanced precision by comparing multiple measurement paths and isolating noise, enabling nanometer-scale measurement capability that overcomes the limitation of conventional single-path interferometers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from conventional two-dimensional interferometric measurement to a multi-dimensional approach by utilizing multiple waveguide cores propagating in different spatial configurations. This dimensional expansion provides additional measurement degrees of freedom, enabling precise detection of nanometer-scale optical thickness changes that are beyond the capability of traditional interferometers.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If micrometric sets are used to measure geometric thickness, then direct measurement is possible, but physical grasp of the layer is required which is difficult for deformable elements or liquids

Engineering Contradiction:
Improvemeasurement operation easeVSAvoidmeasurement applicability to deformable substances
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical micrometric set system with an optical interferometric system based on multicore waveguides. This substitution eliminates the need for physical contact and mechanical grasping of the sample, allowing non-invasive measurement of optical thickness in deformable elements, liquids, and biological substances that cannot be handled by mechanical instruments.

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

Solution Approach 2:

The patent introduces an optical field as an intermediary between the measurement system and the sample. Instead of direct mechanical contact, light propagates through the multicore waveguide and interacts with the sample's optical properties, serving as a mediator that enables measurement of substances that are inaccessible to mechanical probes, including liquids and deformable materials.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If volumetric interferometers are used for thickness measurement, then optical thickness can be measured, but in-situ changes in small layers cannot be detected

Engineering Contradiction:
Improveoptical thickness measurement capabilityVSAvoidin-situ measurement capability
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the measurement function across multiple waveguide cores, allowing distributed sensing along the waveguide length. This segmentation enables localized in-situ measurements at different positions, detecting optical thickness changes in small layers at their specific locations rather than requiring bulk measurement, thus overcoming the limitation of conventional volumetric interferometers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal measurement platform that can detect multiple parameters including optical thickness, temperature, and strain simultaneously using the same multicore waveguide structure. This multi-functional capability allows in-situ detection of various physical quantities in the same measurement system, providing versatility that volumetric interferometers lack.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If standard interferometer structures are used, then basic interference measurement is achieved, but sensitivity for detecting nanometer-scale changes is insufficient

Engineering Contradiction:
Improvedetection reliabilityVSAvoidnanometer-scale change detection
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent merges multiple interferometric paths into a single multicore waveguide structure, combining the measurement capabilities of several interferometers into one integrated system. This merging enhances reliability through redundancy while improving precision by enabling differential measurements that cancel common-mode noise, allowing detection of nanometer-scale changes with high confidence.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a composite waveguide structure combining multiple cores with different properties within a single substrate. This composite architecture allows optimization of each core for specific measurement functions while maintaining overall system integrity, enhancing both reliability and precision for nanometer-scale detection through the synergistic combination of multiple measurement paths.

Inventive Principle:
Principle #40Composite materials

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

Enables precise measurement of nanometer-scale changes in optical thickness and absorption, improving sensitivity and expanding the interferometer's application to various physical parameters, including temperature, strain, and gas concentration, through the detection of interference stripe shifts and contrast changes.

Implementation Method 1

The detector displays interference stripes in a spectral band (wavelength), the shift and/or contrast of which depends on the change of optical thickness and/or the absorption of the layer

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

at least one core is activated with a chemically active substance that changes optical thickness or absorption in response to environmental factors

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3551963B9Waveguide interferometer
Publication Date: 2022.06.15 INPHOTECH
  • EP3551963B9 patent drawingFigure 1~3
  • EP3551963B9 patent drawingFigure 4~6
  • EP3551963B9 patent drawingFigure 7~9

AI summary

A waveguide interferometer, particularly an optical-fiber interferometer, used to measure physical parameters, particularly changes in the optical thickness of layers in the reflective configuration, is characterized in that it contains a light source (1), a coupler (7) made on a waveguide, particularly on a fiber (6), either fibrous or planar, at least double-core, where the face of at least one core is activated, and least one waveguide core (6) is connected directly or indirectly to a signal detector (2) situated on the same side of the multicore fiber as the light source (1).