Optical Fiber Cable Spectral Efficiency via Parameter Optimization

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Solution Overview

Problem

Current optical fiber cables face limitations in spectral efficiency per unit sectional area, with existing technologies unable to effectively increase transmission capacity while maintaining a smaller sectional area, and existing multi-core fibers are not suitable for single-core configurations.

Innovation Solution

The optical fiber cable design includes a ribbon slotted-core structure with specific optical fiber characteristics such as a mode field diameter, effective area, and wavelength dispersion, optimized to satisfy a particular equation that ensures increased spectral efficiency per unit sectional area, using a single core fiber with a core and cladding configuration that minimizes transmission loss and bending losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the sectional area of the optical fiber cable is reduced to increase spatial spectral efficiency, then the transmission capacity per unit area increases, but the transmission loss and bending losses increase

Engineering Contradiction:
Improvespatial spectral efficiencyVSAvoidtransmission loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by precisely controlling the mode field diameter (MFD) to be 10.0 μm or more and the effective area (Aeff) to be 100 μm² or more. These parameter adjustments optimize the balance between spatial spectral efficiency and transmission loss, allowing high-density cable packing while maintaining low transmission characteristics through optimized optical field distribution.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the mode field diameter is increased to reduce transmission loss, then the transmission loss decreases, but the spectral efficiency per unit area decreases

Engineering Contradiction:
Improvetransmission lossVSAvoidspectral efficiency per unit area
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The patent implements parameter changes by establishing specific ranges for mode field diameter (10.0 μm or more) and effective area (100 μm² or more). These controlled parameter changes optimize the trade-off between transmission loss reduction and spectral efficiency maintenance, achieving both low loss and high efficiency through precise optical fiber design.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material principles through the refractive index profile structure, combining different material compositions in the core and cladding layers. This composite structure enables simultaneous optimization of mode field diameter and effective area, achieving the dual goal of reduced transmission loss and maintained spectral efficiency.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the effective area is increased to reduce nonlinear effects, then the transmission quality improves, but the cable sectional area increases

Engineering Contradiction:
Improvetransmission qualityVSAvoidcable sectional area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies parameter changes by setting the effective area (Aeff) to be 100 μm² or more while controlling the mode field diameter to 10.0 μm or more. These parameter optimizations reduce nonlinear optical effects and improve transmission quality while maintaining compact cable dimensions through efficient spatial utilization.

Inventive Principle:
Principle #35Parameter changes

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 design achieves a 30% to 75% increase in spectral efficiency per unit sectional area compared to traditional ribbon slotted-core optical fiber cables, while maintaining low transmission loss and suppressing splice and bending losses, thereby enhancing the overall transmission capacity of the optical fiber cable.

Implementation Method 1

an optical fiber cable having a sectional area of Ac [μm2] and satisfying Expression (1) below, where, N represents a number of the optical fibers, and Aeff represents an effective area [μm2] of each optical fiber

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a relative refractive index difference Δ1 of the core with respect to the cladding may be in a range from 0.30% to 0.35%

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3088930B1Optical fiber cable
Publication Date: 2019.09.18 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP3088930B1 patent drawingFigure 1
  • EP3088930B1 patent drawingFigure 2
  • EP3088930B1 patent drawingFigure 3

AI summary

An optical fiber cable (10) has a sectional area of Ac [µm2] and houses a number N of optical fibers (20). A transmission loss αdB [dB/km], a mode field diameter W [µm], an effective area Aeff [µm2], an effective length Leff [km], and a wavelength dispersion D [ps/nm/km] of each of the optical fibers at a wavelength of 1550 nm satisfy a predetermined equation.