Multicore Fiber Core Identification via E-Band Loss Signatures
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Solution Overview
Problem
Existing multicore fibers face challenges in identifying specific cores due to minimal variation in propagation loss of light at communication wavelength bands, making it difficult to differentiate between them.
Innovation Solution
The multicore fiber design incorporates a specific core with a higher content of hydroxyl groups or a marker positioned closer to the core, resulting in a distinct propagation loss for measurement light outside the communication wavelength band, facilitating easy identification using OTDR or visual inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the difference in propagation loss between cores is reduced, then transmission capacity increases, but core identification becomes difficult
Solution Approach 1:
The patent introduces measurement light with a wavelength other than the communication wavelength band as an intermediary to identify specific cores. This measurement light creates a distinguishable propagation loss difference that allows core identification without affecting the communication signal transmission capacity.
Solution Approach 2:
The patent changes the wavelength parameter of the light used for measurement to a band other than the communication wavelength band. This parameter change enables the detection of propagation loss differences that are not visible at communication wavelengths, thereby facilitating core identification while maintaining high transmission capacity.
2Measurement precision
If measurement light wavelength is in the E-band (1360-1460 nm), then propagation loss difference increases due to hydroxyl group absorption, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by introducing hydroxyl groups specifically into certain cores (specific cores) while keeping other cores free of hydroxyl groups or with lower content. This localized modification creates distinct propagation loss characteristics for identification purposes without requiring uniform precision across all cores.
Solution Approach 2:
The patent converts the typically harmful effect of hydroxyl group absorption (which causes loss) into a beneficial identification mechanism. By intentionally introducing hydroxyl groups into specific cores, the absorption effect becomes a signature that enables core differentiation and identification.
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 allows for easy identification of specific cores by enhancing the propagation loss difference, reducing inter-core crosstalk, and enabling accurate core recognition even with minimal variation in communication wavelength band loss.
Implementation Method 1
In a case where the wavelength of light propagating through the core is 1360 nm or more and less than 1460 nm, which is a so-called E-band, it is known that the loss of light due to the hydroxyl group contained in the core increases
Data Source
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AI summary
A transmission multicore fiber 10 includes a plurality of cores 11a to 11d and a cladding 12 surrounding each of the cores 11a to 11d, in which a propagation loss of measurement light having a wavelength other than a communication wavelength band is different between the core 11a and another core of the cores 11b to 11d.