Multi-core optical fiber leakage reduction portion
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Solution Overview
Problem
Current multi-core optical fibers face challenges in reducing crosstalk between core regions, particularly in long-haul transmission systems where the existing target values for crosstalk may be inadequate, and increasing the relative refractive index difference can lead to increased transmission losses and nonlinearity.
Innovation Solution
A multi-core optical fiber design featuring a leakage reduction portion between adjacent core regions, which can be formed as a ring-shaped region within the cladding with a reduced refractive index, using a refractive index reducer or hollow holes to confine and absorb leakage light, thereby reducing crosstalk without increasing transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the relative refractive index difference between core region and cladding region is increased to reduce crosstalk, then crosstalk between core regions is reduced, but transmission losses and nonlinearity increase
Solution Approach 1:
A leakage reduction portion is introduced as an intermediary structure between adjacent core regions. This portion has a refractive index lower than both the core region and cladding region, creating a barrier that intercepts and redirects leakage light before it can enter adjacent cores. The mediator structure reduces crosstalk without requiring increased refractive index difference in the core-cladding interface, thereby avoiding increased transmission losses
Solution Approach 2:
The refractive index distribution is made non-uniform by introducing the leakage reduction portion with specifically lowered refractive index at strategic locations between cores. This local modification creates asymmetric refractive index profiles that selectively affect leakage light paths while preserving the overall waveguide properties of each core region, reducing crosstalk without globally increasing transmission losses
2Object-affected harmful factors
If the relative refractive index difference is increased to reduce crosstalk, then crosstalk between core regions is reduced, but nonlinearity increases
Solution Approach 1:
The leakage reduction portion acts as a mediator that provides passive optical isolation between cores through refractive index contrast alone, without requiring high nonlinearity materials or structures. The linear refractive index distribution in the leakage reduction portion effectively manages leakage light while maintaining stable, predictable optical properties throughout the fiber structure
Solution Approach 2:
The invention changes the refractive index parameter locally in the leakage reduction portion rather than globally increasing the core-cladding index difference. This parameter modification is precisely controlled and localized, achieving crosstalk reduction through geometric and refractive index optimization while maintaining stable, low-nonlinear material composition throughout the fiber
3Productivity
If multi-core optical fiber is used for long-haul transmission, then transmission capacity is increased, but crosstalk degrades over long distances
Solution Approach 1:
The leakage reduction portion provides continuous passive isolation between cores along the entire fiber length. This mediator structure ensures that leakage light is consistently managed over long propagation distances, preventing cumulative crosstalk degradation and maintaining high transmission capacity for long-haul applications
Solution Approach 2:
The leakage reduction portion is pre-configured into the fiber structure during manufacturing, establishing leakage light management barriers before transmission begins. This preliminary structural arrangement ensures that crosstalk is proactively prevented rather than corrected, maintaining signal integrity over extended transmission distances
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
The design effectively reduces crosstalk between core regions, maintaining high transmission quality even over long distances without degrading propagation performance, by confining and absorbing leakage light, thus ensuring lower crosstalk levels and improved optical SN ratio.
Implementation Method 1
a leakage reduction portion to reduce leakage light in the multi-core optical fiber from each of the core regions, and at least a portion of the leakage reduction portion exists on a straight line connecting core regions together in adjacent core fiber regions
Implementation Method 2
each comprising a core region extending along the optical axis and a cladding region provided on the outer periphery of the core region
Data Source
AI summary
The present invention relates to a multi-core optical fiber having a structure to effectively reduce crosstalk between adjacent core regions among a plurality of core regions. The multi-core optical fiber (1) has a leakage reduction portion (50), at least a portion of which is arranged at a position on a straight line connecting adjacent core regions together among a plurality of core regions (10). The leakage reduction portion (50) reduces leakage light in the multi-core optical fiber (1) from each of the core regions (10), thereby effectively reducing crosstalk between adjacent core regions.