Redundant Ring Resonators for Wavelength Tuning

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Solution Overview

Problem

Ring resonators in optical networks face challenges due to fabrication inaccuracies and environmental changes, which affect their resonance wavelength, requiring effective tuning methods to maintain precise wavelength matching and reduce power consumption.

Innovation Solution

The implementation of redundant ring resonators with heating elements for thermal tuning and p-i-n junctions for electronic tuning, allowing for precise control of resonance wavelengths by adjusting the effective refractive index and optical path length, enabling efficient power management and wavelength alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the resonator size is reduced to increase the number of resonators in a given space, then the device density increases, but the resonance wavelength becomes more sensitive to fabrication variations

Engineering Contradiction:

Improvenumber of resonatorsVSAvoidresonance wavelength accuracy

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameters of the resonators by introducing redundant resonators with different sizes (radii). Each resonator is designed with a specific radius that compensates for fabrication variations, allowing the system to maintain accurate wavelength matching despite manufacturing tolerances. The resonator radius is selected from a set of predetermined values that provide robustness against fabrication errors.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If thermal tuning is applied to compensate for resonance wavelength deviations, then the wavelength accuracy improves, but the power consumption increases

Engineering Contradiction:

Improveresonance wavelength accuracyVSAvoidpower consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-designing redundant resonators with different sizes that are specifically tailored to compensate for expected fabrication variations and environmental changes. This preliminary design approach allows the system to achieve wavelength accuracy without requiring continuous thermal tuning, thereby reducing power consumption while maintaining robust performance.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If the resonator radius is increased to reduce sensitivity to fabrication variations, then the resonance wavelength accuracy improves, but the device area increases

Engineering Contradiction:

Improveresonance wavelength accuracyVSAvoidresonator area

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The patent segments the resonator design into multiple redundant resonators with different sizes rather than using a single large resonator. This segmentation allows the system to achieve the same wavelength accuracy as a large resonator while using smaller individual resonator elements, thereby reducing the overall device area while maintaining robustness against fabrication variations.

Inventive Principle:

Principle #1Segmentation

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 reduces power consumption by allowing for dynamic resonance wavelength adjustment, maintaining accurate wavelength matching across varying environmental conditions and fabrication inaccuracies, leading to improved performance and efficiency in optical transmitters and receivers.

Implementation Method 1

a temperature change in the resonator shifts the effective refractive index of the resonator resulting in deviations from a desired resonance wavelength

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

A heating element is also included to distribute heat evenly to the resonators during thermal tuning

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 3

When the resonator is positioned adjacent to a waveguide within the evanescent field of light propagating along the waveguide, the resonator evanescently couples the particular wavelength of light from the waveguide and traps the light for a period of time

Methodology Applied

Scientific EffectEvanescent coupling:

Implementation Method 4

p-i-n junctions for electronic tuning, allowing for precise control of resonance wavelengths by adjusting the effective refractive index

Methodology Applied

Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentUS8660390B2Redundant ring resonators of varying dimensions to reduce ring resonator tuning requirements

Publication Date: 2014.02.25 HEWLETT PACKARD ENTERPRISE DEV LP

AI summary

Various embodiments of the present invention relate to systems for reducing the amount of power consumed in temperature tuning resonator-based transmitters and receivers. In one aspect, a system comprises an array of resonators (801-806) disposed adjacent to a waveguide (646) and a heating element (808). The heating element is operated to thermally tune the array of resonators so that each resonator in a subset of the array of resonators is in resonance with a wavelength of light traveling in the waveguide.