Cascaded-Mode Resonators Using Mode Coupling for Spectral Control

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Solution Overview

Problem

Existing optical resonators do not effectively utilize the superposition of transverse modes to achieve tailored resonant wavelengths, spectral ranges, and quality factors, limiting their applicability and efficiency in various technological applications.

Innovation Solution

The implementation of cascaded-mode resonators, which utilize mode converters to couple multiple orthogonal transverse modes into supermodes, altering the round-trip phase condition to achieve engineered spectral properties independent of material, frequency, and geometry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional optical resonators are used, then the structure is simple, but the resonant wavelengths, spectral ranges, and quality factors cannot be effectively tailored

Engineering Contradiction:

Improvetailoring of resonant wavelengths, spectral ranges, and quality factorsVSAvoidstructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The resonator is segmented into multiple functional sections: input/output waveguides, mode converters (with periodic modulation), and a resonant cavity. This segmentation allows independent optimization of each section to achieve tailored spectral properties while maintaining overall system manageability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mode converters introduce dynamic mode coupling between different transverse modes, enabling the system to adaptively control resonant wavelengths and quality factors through the interaction of multiple modes rather than relying on fixed geometric parameters

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If multiple transverse modes are coupled into supermodes, then the spectral properties can be engineered, but the device complexity increases

Engineering Contradiction:

Improveengineered spectral propertiesVSAvoidnumber of mode converters and waveguide sections

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The mode converters serve multiple functions: they couple different transverse modes, establish phase relationships between modes, and enable the formation of supermodes. This multi-functionality reduces the need for separate components and manages the complexity of achieving engineered spectral properties

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If mode converters are used to couple orthogonal modes, then the quality factor increases, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvequality factorVSAvoidprecision of mode converters

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The mode converters utilize periodic modulation of waveguide parameters (such as width or refractive index) to achieve mode coupling. By controlling the modulation depth and period, the coupling strength and resonant properties can be tuned, allowing high quality factors to be achieved while providing flexibility in manufacturing tolerances

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

Cascaded-mode resonators exhibit enhanced confinement of wavelengths, modified free spectral ranges, and increased quality factors, enabling efficient light-matter interactions and directional nonlinear effects, while allowing mode-independent behavior.

Implementation Method 1

mode converters coupling two transverse modes in one supermode

Methodology Applied

Scientific EffectMode coupling:

Implementation Method 2

The physics underlying the operation of these resonators can be determined by the constructive interference of electromagnetic waves at specific frequencies, giving rise to the resonance spectrum

Methodology Applied

Scientific EffectConstructive interference: Interference

Implementation Method 3

The mirror can reflect the wave with the second mode of the plurality of orthogonal modes towards the mode converter

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 4

Optical resonators can enable the generation, manipulation, and storage of electromagnetic waves

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS12481101B2Cascaded-mode resonators

Publication Date: 2025.11.25 PRESIDENT & FELLOWS OF HARVARD COLLEGE

AI summary

A device includes a first mode converter and a second mode converter that define a region between the first mode converter and the second mode converter. The region can contain a plurality of orthogonal modes of a wave. The wave, when sent from outside the region and when propagating from the first mode converter towards the second mode converter, can include a first mode of the plurality of orthogonal modes. The second mode converter can convert the wave from the first mode of the plurality of orthogonal modes, to a second mode of the plurality of orthogonal modes that is different from the first mode. The first mode converter can convert the wave to the first mode of the plurality of orthogonal modes.