Ring Resonator Optical Modulator With Feedback for Stable Extinction Ratio

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Solution Overview

Problem

Optical modulators suffer from low extinction ratios due to temperature-induced wavelength drift and increased absorption loss with higher doping concentrations, limiting their performance in high-capacity data communication systems.

Innovation Solution

A modular design incorporating an adjustable ring-shaped resonant cavity with feedback loops and mode converters, which perform successive resonance and modulation processes on the optical signals, and a synchronized manner, and an output waveguide, and a second mode converter, to enhance the extinction ratio by multiplexing optical signals through adjustable ring-shaped resonant cavities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher doping concentrations are used to improve modulation performance, then the modulation efficiency is improved, but the absorption loss increases

Engineering Contradiction:
Improvemodulation efficiencyVSAvoidabsorption loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent changes the physical parameters of the resonant cavity (quality factor, resonance wavelength) and waveguide structure to optimize the balance between modulation efficiency and absorption loss. By adjusting the doping concentration in combination with resonant cavity design, the system achieves high modulation efficiency while controlling absorption loss through parameter optimization rather than simply increasing doping concentration alone.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If temperature changes occur, then the resonance wavelength shifts, but the extinction ratio deteriorates

Engineering Contradiction:
Improvetemperature stabilityVSAvoidextinction ratio
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the resonance wavelength shift due to temperature changes is detected and compensated. The system uses the resonance condition as a feedback signal to adjust the operating point or compensate for wavelength drift, thereby maintaining the extinction ratio despite temperature variations. This feedback approach allows the system to adapt to temperature changes while preserving modulation performance.

Inventive Principle:
Principle #23Feedback

3Device complexity

If a single resonant cavity is used, then the device complexity is low, but the extinction ratio is insufficient

Engineering Contradiction:
Improvestructure complexityVSAvoidextinction ratio
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent combines multiple resonant cavities or integrates the resonant cavity with the modulation function in a unified structure. By merging the resonance enhancement function with the modulation function, the system achieves high extinction ratio without proportionally increasing device complexity. The integrated design allows multiple functions to be accomplished within a compact structure, improving performance while controlling complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 optical modulator improves the extinction ratio by performing two successive resonance adjustments on optical signals, enhancing the amplitude and mode conversion of optical signals, thereby increasing the efficiency and effectiveness of the extinction ratio of the optical signals.

Implementation Method 1

an adjustable ring-shaped resonant cavity coupled to the input waveguide and configured to perform resonance processing on the initial optical signal

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

a first mode converter coupled to the feedback loop waveguide and configured to perform mode conversion processing on the first optical signal

Methodology Applied
Scientific EffectMode conversion:

Implementation Method 3

the adjustable ring-shaped resonant cavity being further configured to perform resonance processing on the second optical signal

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4152082B1Optical modulator and control method therefor
Publication Date: 2025.12.10 ZTE CORP
  • EP4152082B1 patent drawingFigure 1
  • EP4152082B1 patent drawingFigure 2A~2B
  • EP4152082B1 patent drawingFigure 3A~3B

AI summary

An optical modulator and a control method therefor. The optical modulator comprises: an input waveguide (100), configured to receive an initial optical signal; a tunable ring resonator (300), which is coupled to the input waveguide (100) and configured to perform resonance and modulation processing on the initial optical signal and output a first optical signal; a feedback loop waveguide(200), which is coupled to the tunable ring resonator (300) and configured to receive and transmit the first optical signal; a first mode converter (400), which is coupled to the feedback loop waveguide (200) and configured to perform mode conversion processing on the first optical signal and output a second optical signal, the tunable ring resonator (300) being further configured to perform resonance and modulation processing on the second optical signal and output a third optical signal; and an output waveguide (501), coupled to the tunable ring resonator (300) and configured to receive and output the third optical signal.