Loop-Mirror Optical Filter for Stable Tunable Laser Wavelengths

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The instability in the oscillation wavelength of wavelength tunable laser elements due to unmeasurable optical filter characteristics makes accurate control challenging.

Innovation Solution

The design incorporates a first and second loop mirror with optically coupled waveguides and multiplexers/demultiplexers, allowing for the excitation of resonance modes and the transfer of light to an output section where the characteristics of the optical filter can be measured, enabling precise control of the oscillation wavelength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a filter is formed with two ring resonators, then the laser element achieves wavelength tunability, but the oscillation wavelength becomes unstable due to unmeasurable filter characteristics

Engineering Contradiction:

Improvewavelength tunabilityVSAvoidoscillation wavelength stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a feedback mechanism by adding an output section that allows measurement of the optical filter's transmission characteristics. The measured characteristics are fed back to control the tuning wavelength, enabling stable wavelength selection. This resolves the contradiction by making the previously unmeasurable filter characteristics observable and controllable.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary measurement system consisting of the output section, third loop waveguide, and multiplexer/demultiplexer. This intermediary allows indirect measurement of the filter characteristics without disrupting the main laser oscillation path, enabling wavelength stability control while maintaining tunability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the optical filter characteristics are made measurable, then wavelength control precision improves, but the device structure becomes more complex

Engineering Contradiction:

Improvefilter characteristics measurementVSAvoidoptical path structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the measurement function with the existing optical filter structure by integrating the output section and third loop waveguide into the same chip substrate. The multiplexer/demultiplexer combines the measurement light path with the main oscillation path, reducing overall system complexity while enabling precise measurements.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The multiplexer/demultiplexer serves multiple functions: it directs light from the main oscillation path to the output section for measurement, and also directs measurement light back to the gain section. This multi-functionality reduces the need for separate measurement devices, simplifying the overall structure while enabling precise filter characteristic measurement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 allows for the direct measurement of the optical filter's characteristics, stabilizing the oscillation wavelength and improving control over the laser element's operation.

Implementation Method 1

When light is incident on the first access waveguide and the second access waveguide, resonance modes are excited in the first loop mirror and the second loop mirror

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

a first loop mirror, a second loop mirror... The first loop waveguide is optically coupled to the first multiplexer/demultiplexer. The second loop waveguide is optically coupled to the second multiplexer/demultiplexer

Methodology Applied

Scientific EffectOptical resonance: Resonance

Implementation Method 3

The first loop waveguide is optically coupled to the first multiplexer/demultiplexer. The second loop waveguide is optically coupled to the second multiplexer/demultiplexer. The first waveguide is optically coupled to the first multiplexer/demultiplexer and the second multiplexer/demultiplexer

Methodology Applied

Scientific EffectWavelength division multiplexing:

Data Source

PatentUS12197003B2Optical filter and wavelength tunable laser element

Publication Date: 2025.01.14 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

An optical filter includes a first loop mirror, a second loop mirror, a first waveguide optically coupled to the first loop mirror and the second loop mirror, a second waveguide optically coupled to the first loop mirror and the second loop mirror, a first access waveguide optically coupled to the first waveguide, a second access waveguide optically coupled to the second waveguide, and an output section, wherein the first loop mirror includes a first loop waveguide and a first multiplexer/demultiplexer, the second loop mirror includes a second loop waveguide and a second multiplexer/demultiplexer, the output section includes a third loop waveguide, a third multiplexer/demultiplexer, a third waveguide, and a fourth waveguide, the third loop waveguide optically coupled to the second loop waveguide and the third multiplexer/demultiplexer, the third waveguide and the fourth waveguide optically coupled to the third multiplexer/demultiplexer, and the output section.