Dual Ring Resonator Optical Filter for Mode Hop Prevention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing wavelength variable optical filters with ring resonators face challenges in preventing mode hops due to temperature differences between ring resonators, leading to undesirable shifts in the wavelength of external outgoing light, which can be difficult to detect and control without additional elements.

Innovation Solution

Incorporating a configuration with two ring resonators having different perimeters and a control ring to detect and adjust the resonant wavelength of internal outgoing light, preventing mode hops without the need for additional elements by ensuring the highest and second highest peaks in the transmission spectrum are separated, allowing for easier detection of peak interchanges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two ring resonators are used with different perimeters to achieve wavelength variability, then wavelength tuning capability is improved, but mode hops occur due to temperature differences between the ring resonators

Engineering Contradiction:

Improvewavelength tuning capabilityVSAvoidmode hop stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs feedback by detecting the transmission spectrum through the two ring resonators and using this information to control the temperature of each ring resonator independently. This closed-loop control prevents mode hops by maintaining the desired wavelength relationship between the resonators despite temperature variations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the temperature parameter of each ring resonator independently to compensate for thermal effects and maintain stable wavelength operation. By adjusting temperatures as a control parameter, the system prevents mode hops while maintaining wavelength tuning capability

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If additional elements are added to detect and control wavelength shifts, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvewavelength shift detection precisionVSAvoidnumber of additional elements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the existing two ring resonators serve multiple functions: they both filter wavelengths and act as the detection mechanism for wavelength shifts. The transmission spectrum detected through these resonators provides the feedback information needed for control, eliminating the need for separate detection elements

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses itself for detection by measuring the transmission spectrum through the ring resonators that are already part of the wavelength filtering path. This self-detection approach avoids adding external sensing elements while maintaining precise wavelength shift detection

Inventive Principle:

Principle #25Self-service

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 configuration effectively prevents mode hops by ensuring the highest and second highest peaks in the transmission spectrum are distinct, allowing for reliable detection and control of wavelength shifts, thereby maintaining stable laser oscillation at the desired wavelength without requiring additional elements on the semiconductor substrate.

Implementation Method 1

a first ring resonator and a second ring resonator having different perimeters... A free spectral range of a transmission spectrum of the first ring resonator and a free spectral range of a transmission spectrum of the second ring resonator are shifted to each other

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

temperature differences between ring resonators, leading to undesirable shifts in the wavelength of external outgoing light

Methodology Applied

Scientific EffectThermo-optic effect:

Data Source

PatentUS11495935B2Optical filter, and laser light source and optical transceiver using the same

Publication Date: 2022.11.08 DENSO CORP

AI summary

An optical filter includes a first ring resonator a second ring resonator having different perimeters, and a waveguide optically coupled to the first ring resonator and transmit light to the first ring resonator. Light incident on the waveguide is transmitted to the second ring resonator through the first ring resonator. A free spectral range of a transmission spectrum of the first ring resonator and a free spectral range of a transmission spectrum of the second ring resonator are staggered to each other, and are set so that a transmission spectrum of a double ring corresponding to a synthetic spectrum of the transmission spectrum of the first ring resonator and the transmission spectrum of the second ring resonator has a highest first peak at an arbitrary wavelength.