Intracavity Grating for Ring Resonator Efficiency

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Solution Overview

Problem

Microwave-to-optical transducers in optical ring resonators face inefficiency due to coupling with both blue-detuned and red-detuned resonances, limiting conversion efficiency to 50% to a single resonance order.

Innovation Solution

Incorporating an intracavity grating in the optical ring resonator to split or suppress the undesired resonance order, allowing for peak efficiency in microwave-to-optical signal conversion by modulating the evanescent feature and width along the core, thereby isolating the signal pathway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an optical ring resonator is used for microwave-to-optical transduction, then conversion between microwave and optical domains is enabled, but coupling to both blue-detuned and red-detuned resonances limits conversion efficiency to maximum 50%

Engineering Contradiction:

Improveconversion efficiencyVSAvoidresonance coupling

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent extracts or removes one of the two resonance orders (blue-detuned or red-detuned) from the system by introducing an intracavity grating that creates asymmetric coupling. This allows the system to operate exclusively at the desired resonance order, eliminating the 50% efficiency limitation caused by equal coupling to both resonances.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The intracavity grating introduces asymmetry into the optical ring resonator system. The grating creates different coupling conditions for clockwise and counter-clockwise propagating modes, thereby suppressing one resonance order while enhancing the other. This asymmetric coupling enables conversion efficiency to exceed 50% by directing all pump power to the desired signal resonance.

Inventive Principle:

Principle #4Asymmetry

2Power

If both blue-detuned and red-detuned resonances are coupled to, then the optical ring resonator can accept pump photons, but the signal is split between two resonance orders reducing peak efficiency

Engineering Contradiction:

Improvepeak efficiencyVSAvoidsignal distribution loss

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent converts the harmful effect of dual-resonance coupling (which causes signal splitting and efficiency loss) into a beneficial effect. By deliberately designing the intracavity grating with specific parameters, the system exploits the resonance splitting to create a situation where one resonance is enhanced while the other is suppressed, thereby converting the potential loss into a mechanism for achieving peak efficiency at the desired resonance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If an intracavity grating is added to suppress undesired resonance order, then conversion efficiency exceeds 50%, but device complexity increases

Engineering Contradiction:

Improveconversion efficiencyVSAvoidresonator structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The intracavity grating is nested within the existing optical ring resonator structure rather than adding a separate component. The grating is formed as a modulation of the waveguide geometry within the resonator itself, integrating the resonance suppression function directly into the resonator's core structure and minimizing additional complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent achieves resonance order suppression by changing geometric parameters of the intracavity grating (such as grating period, depth, and position) rather than adding complex active components. By carefully selecting these parameters, the system suppresses the undesired resonance through passive geometric design, avoiding the need for complex control mechanisms or additional devices.

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 intracavity grating effectively spoils the unused resonance order, enhancing conversion efficiency from the pump photon frequency to the output signal frequency, achieving higher than 50% efficiency.

Implementation Method 1

an evanescent feature adjacent to the core; a width modulation portion having a width that modulates continuously along a surface of the base portion facing the core to form intracavity grating

Methodology Applied

Scientific EffectEvanescent wave:

Data Source

PatentUS11294257B2Intracavity grating to suppress single order of ring resonator

Publication Date: 2022.04.05 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Microwave-to-optical transducers in an optical ring resonator having intracavity grating to split a single resonance order are provided. In one aspect, a microwave-to-optical transducer includes: an optical ring resonator with intracavity grating; and a microwave signal waveguide optically coupled to the optical ring resonator with the intracavity grating. Microwave-to-optical transducers having multiple pump photon optical ring resonators and multiple signal photon optical ring resonators optically coupled to the optical ring resonator with the intracavity grating are also provided, as is a method of forming a microwave-to-optical transducer, and a method for microwave-optical transduction.