Electro-absorption Modulator Assembly for Compact Polarization Multiplexing

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Solution Overview

Problem

Optical communication systems using polarization multiplex methods are technically complex and require a large installation space due to the need for separate optical paths and polarization combiners.

Innovation Solution

A modulator assembly comprising two electro-absorption modulators that act on separate polarization components of light, with a light generating assembly and polarization converters to rotate the light's polarization, allowing for independent modulation of each component without the need for separate optical paths or a polarization combiner, resulting in a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If separate optical paths and polarization combiners are used for modulating different polarization components, then independent modulation of polarization components is achieved, but device complexity and installation space increase

Engineering Contradiction:

Improvemodulator assembly complexityVSAvoidindependent polarization modulation capability

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The patent combines multiple modulation functions into a single integrated modulator assembly. The first and second electro-absorption modulators are integrated with a polarization beam combiner in a compact configuration, allowing independent modulation of TE and TM polarization components without requiring separate optical paths. This merging of functions reduces device complexity while maintaining the capability for independent polarization modulation.

Inventive Principle:

Principle #5Merging (Combining)

2Area of stationary object

If separate optical paths are used for each polarization component, then independent modulation is enabled, but installation space increases

Engineering Contradiction:

Improvemodulator assembly spaceVSAvoidpolarization multiplexing capability

Core Design Contradiction:

Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent employs a nested configuration where the first and second electro-absorption modulators are integrated within a shared optical path structure. The modulators are positioned such that they sequentially modulate different polarization components of the same light beam, nesting the modulation functions within a compact spatial arrangement. This eliminates the need for separate optical paths while maintaining polarization multiplexing capability.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Device complexity

If polarization combiner is used to combine optical paths, then light waves are combined efficiently, but device complexity increases

Engineering Contradiction:

Improvepolarization combiner structureVSAvoidlight modulation efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent integrates the polarization beam combiner function directly into the modulator assembly structure. The combiner is positioned to receive modulated light from both electro-absorption modulators and combine them in a single optical output path. This merging of the combiner function with the modulation functions eliminates the need for separate combiner components and reduces overall device complexity while maintaining efficient light combination.

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 solution simplifies and compacts the modulator assembly, reducing the complexity and space requirements of optical communication systems by enabling independent modulation of light polarization components, thus facilitating more efficient data transmission.

Implementation Method 1

a first and a second electro-absorption modulator, which each at least substantially only act on one polarization component of incident light

Methodology Applied

Scientific EffectElectro-absorption: Absorption (EM radiation)

Implementation Method 2

a polarization converter (e.g. a polarization rotator) for changing the polarization direction of the light exiting from the first electro-absorption modulator

Methodology Applied

Scientific EffectPolarization rotation: Polarisation

Data Source

PatentUS11281016B2Modulator assembly and method for modulating light

Publication Date: 2022.03.22 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

A modulator assembly for modulating light comprising a first and a second electro-absorption modulator which each at least substantially only act on a polarization component of incident light; a light generating assembly for generating light which includes a first and a second polarization component; a first electro-absorption modulator for modulating the light generated by the light generating assembly, wherein the first electro-absorption modulator at least substantially only modulates the first polarization component of the light, so that the light exiting from the first electro-absorption modulator includes a modulated and an unmodulated polarization component; a polarization converter for changing the polarization direction of the light exiting from the first electro-absorption modulator. The light exiting from the polarization converter couples into the second electro-absorption modulator and is polarized such that by means of the second electro-absorption modulator a modulation at least substantially is effected only of the previously unmodulated polarization component.