Electro-Optic Modulator Mounting to Suppress Crystal Birefringence

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Solution Overview

Problem

Existing electro-optic modulators face issues with pressure-induced birefringence in crystalline materials, which affects the efficiency of modulation, and soft formable materials used to reduce pressure can absorb energy and further reduce efficiency.

Innovation Solution

An electro-optic modulator design featuring elastically deformable portions on the walls of the cavity that contact the modulator element, allowing for secure holding without excessive pressure, using a resilient material like copper that minimizes energy absorption and supports brittle crystals like Potassium Dideuterium Phosphate, with a pressing element to adjust frictional force for optimal positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the modulator element is clamped between two opposing walls to hold it firmly in place, then the modulator element is securely positioned, but pressure or stress is exerted onto the modulator element causing undesirable birefringence

Engineering Contradiction:
Improvepositioning stabilityVSAvoidbirefringence
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces rigid clamping walls with an elastically deformable membrane that conformally contacts the modulator element. This membrane provides gentle holding force without the high localized pressure that causes birefringence, while still maintaining secure positioning through elastic deformation and friction.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the mechanical properties of the contacting surface from rigid to elastically deformable. This parameter change allows the membrane to adapt its hardness and compliance to match the modulator element, providing secure holding without excessive pressure that would induce birefringence.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a layer of soft formable material is provided between the modulator element and the walls to reduce pressure, then pressure-induced birefringence is reduced, but the paste-like material absorbs energy of the standing wave reducing modulation efficiency

Engineering Contradiction:
ImprovebirefringenceVSAvoidenergy absorption
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent uses an elastically deformable membrane made of non-absorbing material that provides the necessary compliance to reduce pressure on the modulator element while maintaining low energy absorption characteristics. The membrane's elastic properties allow it to deform under pressure without dissipating significant energy, unlike paste-like materials.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs composite construction combining an elastically deformable membrane with a rigid support structure. This composite approach allows the membrane to provide gentle conformal contact that reduces birefringence while the rigid support ensures structural integrity and minimizes energy absorption, creating a material system with both compliance and low loss.

Inventive Principle:
Principle #40Composite materials

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 solution effectively suppresses birefringence and maintains high modulation efficiency by reducing pressure on the modulator element, enabling the use of sensitive crystals and minimizing energy absorption, thus enhancing the performance of the electro-optic modulator.

Implementation Method 1

an elastically deformable portion that is adapted to deform upon application of a force and to return to its original shape and position when the force is removed

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The resonant cavity is configured to accommodate a standing wave of a modulating energy, for example microwave energy, that causes a change in the refractive index of the crystalline material

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 3

The elastically deformable portion contacts the modulator element... The modulator element is held between the first wall and the second wall of the cavity, further preferably by friction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3809192B1Electro-optic modulator
Publication Date: 2023.12.06 QUBIG GMBH
  • EP3809192B1 patent drawingFigure 1
  • EP3809192B1 patent drawingFigure 2

AI summary

An electro-optic modulator (1) for modulating a beam of electro-magnetic radiation comprise a cavity (3) having a first wall (5-10) and a second wall (5-10) opposed to each other and a modulator element (4) arranged within the cavity (3). The first wall (5-10) and the second wall (5-10) are adapted to receive the modulator element (4) in an interspace formed between them and at least the first wall (5-10) comprises an elastically deformable portion (17, 18) that contacts the modulator element (4).