Stabilized SBS Laser with Ultra-Low Phase Noise

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Solution Overview

Problem

Existing stimulated Brillouin scattering lasers face challenges in achieving ultra-low phase noise, which is crucial for high-performance resonator fiber optic gyroscopes, due to difficulties in optimizing the pump laser stabilization process and SBS laser operation.

Innovation Solution

A system and method for stabilized stimulated Brillouin scattering lasers are introduced, utilizing a tunable laser source with a first optical loop path for the pump beam and a separate second optical loop path with phase modulated light for stabilizing the laser, employing a Pound-Drever-Hall servo loop to lock the frequency to a ring cavity resonance, thereby generating a Stimulated Brillouin Scattering beam with ultra-low phase noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single ring cavity is used for both pump laser and SBS laser, then device complexity is reduced, but it becomes difficult to independently optimize pump laser stabilization and SBS laser operation

Engineering Contradiction:
Improveoptical path configurationVSAvoidindependent optimization capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent divides the single ring cavity into two separate optical loop paths: a first optical loop path for the pump laser and a second optical loop path for the SBS laser. This segmentation allows independent optimization of each laser path while maintaining the benefits of a unified cavity structure, resolving the contradiction between device simplicity and optimization flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a modulated light beam as an intermediary that couples into the ring cavity to enable Pound-Drever-Hall frequency stabilization of the pump laser without directly interfering with the SBS laser operation. This intermediary mechanism allows independent control and optimization of both laser paths within the shared cavity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If pump laser frequency is rapidly tuned in an auto-tracking feedback loop, then ultra-narrow linewidth radiation is achieved, but the system complexity increases

Engineering Contradiction:
Improvelinewidth precisionVSAvoidfeedback loop configuration
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a Pound-Drever-Hall frequency stabilization feedback loop that uses a modulated light beam coupled into the ring cavity. The feedback mechanism monitors the pump laser frequency and rapidly tunes it to maintain resonance with cavity modes, achieving ultra-narrow linewidth radiation while providing a systematic approach to managing the feedback complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The modulated light beam serves as an intermediary carrier for the feedback signal, enabling frequency stabilization without directly modulating the pump laser. This intermediary approach simplifies the feedback loop configuration by separating the stabilization function from the main laser path.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If separate optimization of pump laser stabilization and SBS laser operation is attempted, then each can be optimized independently, but device complexity increases

Engineering Contradiction:
Improvelaser stabilization performanceVSAvoidoptical path structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the optical system into distinct first and second optical loop paths for pump laser and SBS laser respectively, allowing separate optimization of each path while maintaining overall system reliability. The segmentation enables independent parameter optimization without compromising the other laser's performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges the pump laser and SBS laser operations into a single shared ring cavity, reducing overall device complexity while maintaining separate optical paths for independent optimization. This combining approach allows both lasers to benefit from the same cavity resonance while avoiding the complexity of completely separate cavity systems.

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

This approach effectively reduces phase noise and relative intensity noise in the SBS laser, enabling improved performance for resonator fiber optic gyroscopes by separating the pump and modulated light beams into different paths within a single ring cavity, allowing for independent optimization of pump power and modulation.

Implementation Method 1

creating a phase modulated light beam by applying a phase modulation to the first light beam

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Implementation Method 2

locking a frequency of the laser light to a resonance frequency of a ring cavity using the phase modulated light beam and a Pound-Drever-Hall servo loop

Methodology Applied
Scientific EffectPound-Drever-Hall frequency locking: Resonance

Implementation Method 3

generating a Stimulated Brillouin Scattering light beam in the ring cavity from the second light beam

Methodology Applied
Scientific EffectStimulated Brillouin scattering: Brillouin Scattering

Data Source

PatentEP2927636B1Systems and methods for stabilized stimulated brillouin scattering lasers with ultra-low phase noise
Publication Date: 2019.05.08 HONEYWELL INTERNATIONAL INC
  • EP2927636B1 patent drawingFigure 1
  • EP2927636B1 patent drawingFigure 2
  • EP2927636B1 patent drawingFigure 3

AI summary

Systems and methods for stabilized stimulated Brillouin scattering lasers with ultra-low phase noise are provided. In one embodiment, a method for producing a Stimulated Brillouin Scattering (SBS) beam comprises: generating laser light from a tunable laser source; splitting the laser light into a first light beam and a second light beam; creating a phase modulated light beam by applying a phase modulation to the first light beam; locking a frequency of the laser light to a frequency of a ring cavity using the phase modulated light beam and a Pound-Drever-Hall servo loop coupled to the tunable laser source; coupling the second light beam into the ring cavity in a direction of travel opposite to that of the phase modulated light beam; generating a Stimulated Brillouin Scattering light beam in the ring cavity from the second light beam; and outputting the Stimulated Brillouin Scattering light beam.