Optical Amplifier Reusing Residual Pump Light in Multi-Core Fiber

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Solution Overview

Problem

Optical amplifiers using multi-core optical fibers face low light intensity amplification efficiency due to low absorption efficiency of excitation light in the optical amplification medium when employing the cladding excitation method.

Innovation Solution

An optical amplification apparatus and method that reintroduces residual excitation light into the optical amplification medium, using multiplexing and demultiplexing means to increase absorption efficiency through a spatial optical system, specifically utilizing a dichroic mirror or spatial light modulator to separate and reuse excitation light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the cladding excitation method is used to amplify optical signals in multi-core optical fiber, then the optical amplifier configuration can be based on conventional single-core excitation method, but the absorption efficiency of excitation light becomes low and light intensity amplification efficiency becomes extremely low

Engineering Contradiction:

Improvecompatibility with multi-core optical fiberVSAvoidabsorption efficiency of excitation light

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent introduces residual excitation light from the output end back to the input end of the optical amplification medium, creating a continuous circulation of excitation light. This allows the excitation light to interact with the optical amplification medium multiple times, significantly improving absorption efficiency and light intensity amplification efficiency while maintaining cladding excitation compatibility

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

Instead of discarding the residual excitation light that exits the optical amplification medium, the patent recovers this light by introducing it back into the input end of the optical amplification medium. This recovery process maximizes the utilization of excitation light energy, converting what would be wasted energy into useful amplification power

Inventive Principle:

Principle #34Discarding and recovering

2Loss of energy

If residual excitation light is reintroduced into the optical amplification medium, then absorption efficiency and light intensity amplification efficiency are improved, but the device complexity increases due to additional multiplexing and demultiplexing means

Engineering Contradiction:

Improvelight intensity amplification efficiencyVSAvoidconfiguration complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent separates the signal light and residual excitation light using wavelength division multiplexing/demultiplexing techniques. By segmenting the light paths based on wavelength, the system can independently manage excitation light circulation while maintaining signal light transmission, reducing interference and simplifying the overall system design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses multiplexing and demultiplexing means as intermediary devices to manage the interaction between signal light and residual excitation light. These intermediaries enable the efficient combination and separation of different light wavelengths, facilitating the residual excitation light introduction while maintaining system organization and reducing direct complexity

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

Enhances absorption efficiency of excitation light in the optical amplification medium, improving light intensity amplification efficiency and reducing electric power consumption.

Implementation Method 1

enhances absorption efficiency of excitation light in the optical amplification medium

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

space propagation type wavelength demultiplexing means for wavelength-demultiplexing the signal light and the residual excitation light by means of a spatial optical system

Methodology Applied

Scientific EffectWavelength demultiplexing:

Data Source

PatentUS12374851B2Optical amplification apparatus and optical amplification method

Publication Date: 2025.07.29 NEC CORP

AI summary

An optical amplification apparatus includes an optical amplification medium, having a gain in a wavelength band of signal light, configured to receive the signal light; excitation light introduction means for introducing, into the optical amplification medium, excitation light to excite the optical amplification medium; and residual excitation light introduction means for introducing, into the optical amplification medium, residual excitation light output from the optical amplification medium, the residual excitation light having a wavelength component of the excitation light, wherein the residual excitation light introduction means includes, on a side of one end of the optical amplification medium, residual excitation light multiplexing means for multiplexing the signal light and the residual excitation light, and on a side of another end of the optical amplification medium, space propagation type wavelength demultiplexing means for wavelength-demultiplexing the signal light and the residual excitation light by means of a spatial optical system.