Resonant Optical Modulators with Variable Resonance Frequency

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing optical modulators face challenges in achieving high-speed and high-sensitivity modulation while maintaining energy efficiency, particularly in wavelength-division-multiplexed systems, due to limitations in resonance frequency variability and absorption properties, leading to inefficiencies in cascading and wavelength selectivity.

Innovation Solution

The design of resonator-based optical modulators with variable resonance frequency and absorption coefficients, utilizing optically active resonators and coupling structures to optimize transfer functions between input and output ports, allowing for continuous modulation and improved energy efficiency through strategic placement of transmission zeros and phase shifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If resonance frequency is varied to achieve high-speed modulation, then modulation speed is improved, but sensitivity deteriorates due to broad bandwidth requiring strong actuation signals

Engineering Contradiction:

Improvemodulation speedVSAvoidmodulation sensitivity

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent changes the resonance frequency parameter of the optical resonator to achieve high-speed modulation. By tuning the resonance frequency dynamically, the modulator can respond quickly to modulation signals while maintaining sharp spectral features for high sensitivity through proper design of the resonator's quality factor and coupling parameters.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If sharp amplitude changes are implemented for high sensitivity, then modulation sensitivity is improved, but bandwidth increases requiring strong actuation signals

Engineering Contradiction:

Improvemodulation sensitivityVSAvoidmodulation bandwidth

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The patent implements dynamic control of the optical resonator's resonance frequency through external actuation (such as thermal, electro-optic, or mechanical tuning). This dynamic adjustment allows the system to achieve sharp amplitude changes for high sensitivity while controlling the bandwidth through proper design of the resonator's quality factor and coupling parameters.

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If Lorentzian response is used for resonance, then energy efficiency is improved, but extinction ratio deteriorates because transmission does not roll off to zero off resonance

Engineering Contradiction:

Improveenergy efficiencyVSAvoidextinction ratio

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent employs a composite structure combining an optical resonator with wavelength-selective filtering elements. This composite approach maintains the energy efficiency of resonant structures while achieving sharp roll-off characteristics for high extinction ratio through the combined effect of the resonator's Lorentzian response and the wavelength-selective filter's sharp transmission edges.

Inventive Principle:

Principle #40Composite materials

4Reliability

If resonance is shifted by more than one bandwidth to achieve low transmission, then extinction ratio is improved, but energy consumption increases

Engineering Contradiction:

Improveextinction ratioVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the resonance frequency tuning range to achieve the required extinction ratio with minimal frequency shift. By carefully designing the resonator's quality factor and coupling parameters, the system achieves high extinction ratio with frequency shifts less than one bandwidth, reducing the energy required for modulation while maintaining reliable signal extinction.

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

This approach enhances modulation speed, sensitivity, and energy efficiency, enabling efficient cascading of modulators and improved wavelength selectivity, thereby overcoming the limitations of existing technologies.

Implementation Method 1

Energy-efficient modulators may be optically resonant structures, such as silicon microring resonators coupled to a waveguide

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

two coupling structures between the two waveguides. One of the coupling structures is an 'optically active resonator'

Methodology Applied

Scientific EffectOptical coupling:

Implementation Method 3

This is the case, for example, when modulation is achieved with carrier injection in silicon, i.e., using the carrier-plasma effect

Methodology Applied

Scientific EffectCarrier-plasma effect:

Data Source

PatentUS8340478B2Resonant optical modulators

Publication Date: 2012.12.25 MASSACHUSETTS INST OF TECH

AI summary

Disclosed are optical modulators that have two coupling paths or structures between an input port to an output port, at least one of which includes an optical resonator.