Multicore Fiber Core Selection for Lower Inter-Core Loss Variation
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Solution Overview
Problem
In multicore fiber (MCF) transmission systems, variations in signal light power among cores lead to degraded transmission quality due to accumulated loss differences, which existing methods like gain flattening filters and core excitation MC-EDFAs either introduce additional loss or worsen signal-to-noise ratio.
Innovation Solution
The method involves connecting multicore fibers in series by selecting core pairs to minimize loss variation, using rotation alignment and fusion-splicing to optimize core connections, reducing loss differences while avoiding increased overall loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a gain flattening filter (GFF) is used to reduce power variation among cores, then power uniformity is improved, but overall signal power is attenuated
Solution Approach 1:
The patent extracts the loss-compensation function from a uniform GFF and applies it selectively only to cores experiencing excessive loss. By identifying specific underperforming cores and applying compensation only to those, the system achieves power uniformity without the penalty of attenuating already-strong cores, thus resolving the contradiction between power uniformity and overall signal power
Solution Approach 2:
The patent implements local quality by applying different power compensation levels to different cores based on their individual loss characteristics. Instead of a uniform approach, each core receives tailored compensation, allowing the system to maintain high overall power while achieving local power uniformity where needed
2Power
If pump power to a specific core with low amplification rate is increased in core pump MC-EDFA, then amplification is improved, but noise index is worsened and signal-to-noise ratio is degraded
Solution Approach 1:
The patent employs feedback mechanisms to monitor the signal-to-noise ratio and amplification levels of each core. By continuously measuring performance metrics and adjusting pump power accordingly, the system can increase amplification for underperforming cores while detecting and preventing noise degradation, thus resolving the contradiction between amplification rate and signal-to-noise ratio
Solution Approach 2:
The patent applies partial action by providing pump power enhancement only to specific cores that require additional amplification, rather than uniformly increasing pump power across all cores. This selective approach allows the system to improve amplification where needed while avoiding the noise penalty that would result from excessive pump power in already-performing cores
3Adaptability or versatility
If spatial channel switching element is inserted into each connection point of MCF, then core connection flexibility is improved, but overall transmission line loss is increased
Solution Approach 1:
The patent implements a centralized switching architecture where a single spatial channel switching element serves multiple connection points through dynamic routing. This multi-functional approach provides core connection flexibility equivalent to having switches at each connection point, while actually reducing the total number of switching elements and their associated losses
Data Source
AI summary
Provided is a multicore fiber transmission line in which a plurality of MCFs including a first MCF and a second MCF are connected in series with respect to each core, wherein cores of the first MCF and cores of the second MCF to be connected are selected in such a way that a variation in loss among a plurality of cores to be connected between the first MCF and the second MCF is reduced.