Multicore Optical Amplifier Core Segmentation for Crosstalk Reduction

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Solution Overview

Problem

Optical amplification devices using multicore optical fibers face challenges in efficiently amplifying signal light due to limitations in increasing the number of cores, which reduces power utilization efficiency and amplification capacity.

Innovation Solution

The design includes an optical fiber amplification unit with a larger number of amplification cores than transmission cores, utilizing a multicore optical fiber with a double-clad structure and rare-earth ion doping, and a fan-in/fan-out connection system to efficiently propagate signal light through multiple amplification core groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the number of cores of a multicore optical fiber amplifier is increased to improve power efficiency of excitation light, then power efficiency is improved, but the inter-core distance increases causing crosstalk and the cladding diameter becomes larger than that of single-mode optical fiber

Engineering Contradiction:

Improvepower efficiency of excitation lightVSAvoidcrosstalk

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The amplification function is segmented between two distinct components: a multicore optical fiber amplifier with fewer cores (optimized for power efficiency) and a separate fan-in/fan-out unit. This segmentation allows each component to be optimized independently - the amplifier for power efficiency and the fan-in/fan-out for core mapping - resolving the contradiction between power efficiency and crosstalk suppression.

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If the number of cores of a multicore optical fiber amplifier is increased to improve power efficiency, then power efficiency is improved, but the cladding diameter becomes larger than that of single-mode optical fiber

Engineering Contradiction:

Improvepower efficiency of excitation lightVSAvoidcladding diameter

Core Design Contradiction:

Use of energy by moving objectVSArea of stationary object

Solution Approach 1:

The system is segmented into a compact multicore amplifier with fewer cores (small cladding diameter) and an external fan-in/fan-out unit. This allows the amplifier to maintain a small cladding diameter suitable for integration while the fan-in/fan-out handles the core multiplication, resolving the contradiction between power efficiency and compact size.

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If the number of cores of a multicore optical fiber amplifier is decreased to match transmission fiber cores, then crosstalk is suppressed, but power efficiency of excitation light is reduced

Engineering Contradiction:

ImprovecrosstalkVSAvoidpower efficiency of excitation light

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The fan-in/fan-out unit acts as an intermediary between the transmission fiber and the amplifier. It maps multiple transmission cores to a smaller number of amplification cores, allowing the amplifier to operate with fewer cores (high power efficiency) while maintaining compatibility with multi-core transmission fibers (low crosstalk).

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The fan-in/fan-out unit performs a dimensional transformation by mapping N-dimensional input signals from N transmission cores to M-dimensional output signals for M amplification cores (where N > M). This dimensional reduction allows the system to achieve both low crosstalk (through proper core mapping) and high power efficiency (through reduced amplifier core count).

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 configuration improves power efficiency of excitation light per core, enabling efficient amplification of signal light and increasing communication capacity while reducing crosstalk and space requirements.

Implementation Method 1

an optical fiber amplification unit including a plurality of amplification cores

Methodology Applied

Scientific EffectStimulated emission:

Implementation Method 2

utilizing a multicore optical fiber with a double-clad structure and rare-earth ion doping

Methodology Applied

Scientific EffectRare-earth ion doping:

Data Source

PatentUS20240235684A1Optical amplification device and optical amplification method

Publication Date: 2024.07.11 NEC CORP

AI summary

In an optical amplification device using a multicore optical fiber, it is difficult to efficiently amplify signal light. In order to solve this problem, an optical amplification device according to the present disclosure includes an optical fiber amplification unit including a plurality of amplification cores, a first connection unit being connected to one end of the optical fiber amplification unit, and a second connection unit being connected to another end of the optical fiber amplification unit, wherein the first connection unit is configured in such a way as to connect a transmission fiber including a plurality of transmission cores to the optical fiber amplification unit, and the number of the plurality of amplification cores is larger than the number of the plurality of transmission cores.