Multi-Core Amplifying Fiber Layout for Efficient L-Band Cladding Pumping
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Solution Overview
Problem
Existing optical fiber amplifiers for the L band (1565 to 1610 nm) suffer from reduced amplification efficiency due to unclear structural conditions, despite efforts to increase the core-to-cladding ratio (Rcc) for improved efficiency, as seen in C band amplifiers.
Innovation Solution
An optical fiber amplifier with two or more cores in its cladding, a core density of 0.0008 μm² or more, and core radius between 1 μm and 3.5 μm, utilizing a cladding pumping type with a pump light combiner and multi-mode pump light source, and adjusting the fiber length for optimal L band amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the core-to-cladding ratio (Rcc) is increased to improve amplification efficiency, then the pump light absorption increases, but the overlap between pump light propagation region and core region decreases
Solution Approach 1:
The patent optimizes specific parameters including core radius (1-3.5 μm), core density (0.0008 μm² or more), and fiber length to achieve high amplification efficiency in the L band while maintaining effective pump light absorption through controlled core-to-cladding ratio
Solution Approach 2:
The patent employs multi-mode pump light propagation in the cladding region, allowing dynamic light distribution that enhances absorption in the doped core regions while maintaining reliability through mode coupling effects
2Reliability
If the fiber length is increased to improve L band amplification, then the amplification gain increases, but the pump light absorption becomes insufficient
Solution Approach 1:
The patent determines optimal fiber length parameters specifically for L band amplification that balance amplification gain and pump light absorption, differing from C band optimization
Solution Approach 2:
The patent uses multiple doped core regions distributed along the fiber length, creating segmented absorption zones that maintain efficient pump light utilization throughout the extended fiber length for high gain amplification
3Device complexity
If a cladding pumping type amplifier is used to simplify the structure and improve power efficiency, then temperature control requirements are reduced, but the pump light absorption in the core region decreases
Solution Approach 1:
The patent transitions from core-based pumping to cladding-based pumping, utilizing the radial dimension of light propagation to deliver pump light through the cladding region into multiple doped core regions, simplifying structure while maintaining absorption through geometric optimization
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 amplification efficiency of L band signals by optimizing structural parameters, achieving high power conversion efficiency (PCE) through specific core density and radius configurations.
Implementation Method 1
a pump light combiner for injecting a pump light into a cladding region of the optical fiber for amplification
Implementation Method 2
signal light and pump light (mainly light with 980 nm or 1480 nm as the condition of erbium-doped optical fiber (EDF) using erbium) for exciting a rare earth element are injected into an optical fiber for amplification
Implementation Method 3
a small pump light quantity absorbed in an optical fiber for amplification as compared with the core pumping system
Data Source
AI summary
An object of the present invention is to improve efficiency of an amplifying L band signal.The present disclosure is an optical fiber doped with a rare earth element for amplification, in which the optical fiber for amplification includes two or more cores in a cross section of a cladding, a core density C obtained by dividing number of cores by a cladding area is 0.0008 μm2 or more, and a core radius a is 1 μm or more and 3.5 μm or less.