Ring Laser Gyroscope Polarizer for Signal Clarity

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Solution Overview

Problem

Ring laser gyroscopes often experience noisy or low laser power due to multiple polarization modes existing in the resonant cavity, which affects their operational effectiveness.

Innovation Solution

Implementing polarizers outside the resonant cavity to allow only substantially one polarization mode of laser light to pass to optical sensors, improving signal clarity and strength by using polarizers in various configurations, such as on photo detector devices or laser blocks, to filter and direct laser beams with a single polarization mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple polarization modes are allowed in the resonant cavity, then the laser power may be higher, but the noise increases and operational effectiveness decreases

Engineering Contradiction:
Improvelaser powerVSAvoidoperational effectiveness
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent extracts and eliminates unwanted polarization modes from the resonant cavity by introducing a polarizer. The polarizer selectively transmits only the desired polarization mode while blocking other polarization modes, thereby removing the source of noise and improving operational effectiveness while maintaining sufficient laser power through the optimized single-mode configuration

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the polarization state parameter by introducing a polarizer that enforces a specific polarization mode. This parameter change transforms the multi-mode polarization state into a single-mode polarization state, reducing noise and improving signal quality while maintaining operational effectiveness

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If polarizers are added to filter polarization modes, then signal clarity and noise reduction improve, but device complexity increases

Engineering Contradiction:
Improvesignal clarityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The polarizer serves multiple functions simultaneously: it filters unwanted polarization modes to reduce noise, defines the polarization state for optimal laser power extraction, and provides a stable reference for interference measurements. By consolidating these functions into a single component, the patent achieves improved signal clarity without proportionally increasing device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The polarizer acts as an intermediary element between the multi-mode laser output and the single-mode detection requirement. It mediates the polarization states by selectively transmitting the desired mode while blocking others, thereby improving signal clarity and reducing noise without requiring complex post-processing or additional active control mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reduces noise, enhances signal clarity, and optimizes performance by minimizing Angle Random Walk (ARW) quantum limit, thereby improving the ring laser gyroscope's operational efficiency and accuracy.

Implementation Method 1

A polarizer is in optical communication with the optical sensor. The polarizer is configured to pass laser light having substantially one polarization mode to the optical sensor

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

Electrical potentials applied to the lasing gas generate counter-propagating laser beams in the resonant cavity

Methodology Applied
Scientific EffectElectrical discharge in gas: Townsend Discharge

Implementation Method 3

Reflective surfaces are positioned at the intersection of each of the passages

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2894434B1Ring laser gyroscope with integrated polarization
Publication Date: 2019.08.21 HONEYWELL INTERNATIONAL INC
  • EP2894434B1 patent drawingFigure 1A
  • EP2894434B1 patent drawingFigure 1B
  • EP2894434B1 patent drawingFigure 2A~2B

AI summary

A ring laser gyroscope (100) comprises a laser block (112) that defines an optical closed loop pathway configured to contain a lasing gas. A plurality of mirror structures (120, 122, 124) are respectively mounted on the laser block, with each of the mirror structures having a respective reflective surface (130, 132, 134) that is in optical communication with the optical closed loop pathway. A plurality of electrodes(140, 142, 144) are coupled to the laser block, with the electrodes configured to generate a pair of counter-propagating laser beams (160) from the lasing gas in the optical closed loop pathway. At least one optical sensor (208) is coupled to one of the mirror structures, with the optical sensor in optical communication with the closed loop pathway. A polarizer (210) is in optical communication with the optical sensor. The polarizer (210) is configured to pass laser light having substantially one polarization mode to the optical sensor.