Multi-core fiber self-homodyne detection with pilot tone

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Solution Overview

Problem

Current optical communication systems face challenges in implementing efficient self-homodyne detection in space-division multiplexed systems, particularly in reducing transmission capacity loss and improving reception characteristics using inexpensive light sources.

Innovation Solution

A space-division multiplexing apparatus utilizing a multi-core fiber, where one core is dedicated for pilot-tone transmission to enable self-homodyne detection in the remaining cores, incorporating a pilot-tone guiding unit and a self-homodyne detection unit, with an optical frequency comb generator and optical path length adjustment to optimize signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If one core of multi-core fiber is used for pilot tone transmission to enable self-homodyne detection, then reception characteristics are improved, but transmission capacity is reduced due to capacity reduction ratio

Engineering Contradiction:
Improvereception characteristicsVSAvoidtransmission capacity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent divides the multi-core fiber into functionally distinct segments: one core is dedicated to pilot tone transmission for self-homodyne detection, while the remaining cores are allocated for data signal transmission. This segmentation allows the system to achieve improved reception characteristics through coherent detection while minimizing capacity loss by efficiently utilizing the available cores for data transmission.

Inventive Principle:
Principle #1Segmentation

2Reliability

If self-homodyne detection is implemented in space-division multiplexed systems, then system performance is enhanced, but device complexity increases

Engineering Contradiction:
Improvesystem performanceVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a universal detection architecture where the self-homodyne detection mechanism is applied across multiple cores simultaneously. The detection unit processes pilot tones from all cores using a unified approach, reducing the need for separate detection systems for each core and thereby limiting the increase in device complexity while still enhancing overall system performance.

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

3Object-generated harmful factors

If pilot tone is transmitted alongside data signals in the same fiber, then interference is minimized, but signal quality may be affected

Engineering Contradiction:
ImproveinterferenceVSAvoidsignal quality
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent physically segments the transmission medium by allocating different cores for different signal types. Pilot tones are transmitted in one core while data signals are transmitted in other cores, which minimizes interference between signals. The spatial separation through core isolation maintains signal quality by preventing cross-talk and nonlinear interactions that would occur if signals shared the same core.

Inventive Principle:
Principle #1Segmentation

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 enables coherent transmission with a simple configuration, reduces capacity reduction ratios, and improves reception characteristics by using a pilot tone transmitted alongside data signals, minimizing interference and enhancing system performance.

Implementation Method 1

a multi-core fiber 11 having multiple cores

Methodology Applied
Scientific EffectOptical fiber transmission: Optical Fibre

Implementation Method 2

self-homodyne detection of data signals in the remaining cores 16

Methodology Applied
Scientific EffectSelf-homodyne detection: Homodyne Detection

Data Source

PatentEP2892167B1Space division multiplexing apparatus including multi-core fiber and selfhomodyne detection method
Publication Date: 2018.10.17 NAT INST OF INFORMATION & COMM TECH
  • EP2892167B1 patent drawingFigure 1~3
  • EP2892167B1 patent drawingFigure 4
  • EP2892167B1 patent drawingFigure 5

AI summary

To provide a self-homodyne detection communication system capable of using a space-division multiplexing signal as a signal for communication. The present invention relates to a space-division multiplexing apparatus 12 including a multi-core fiber 11 having multiple cores. The space-division multiplexing apparatus 12 uses cores other than a core 13 for self-homodyne detection among the multiple cores included in the multi-core fiber 11 as cores 16 for communication. The space-division multiplexing apparatus is configured to include a pilot-tone guiding unit 14 and a self-homodyne detection unit 15.