Mode-Dependent Loss Measurement for Coupled Multi-Core Fibers
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Solution Overview
Problem
Existing mode-dependent loss measurement devices for coupled multi-core optical fibers face high costs and errors due to the need to measure transmittance for each spatial mode, leading to increased measurement times proportional to the square of the number of spatial modes, making it difficult to manage mode-dependent loss effectively.
Innovation Solution
A mode-dependent loss measurement device that includes a light source, a light receiver, and a mode coupled state change mechanism, such as a disturbance application unit, wavelength change unit, or phase modulation means, to analyze variations in optical powers and calculate mode-dependent loss by changing the mode coupled state of an excitation optical fiber, allowing for low-cost measurement with reduced errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmittance is measured for each spatial mode using existing measurement devices, then measurement accuracy is improved, but measurement time increases proportionally to the square of the number of spatial modes and device complexity increases
Solution Approach 1:
The patent combines multiple spatial mode measurements into a single integrated measurement process. By using mode coupled state change means to dynamically switch between spatial modes and a single light receiver to detect all modes sequentially, the system merges what would otherwise require multiple separate measurement setups, reducing measurement time while maintaining accuracy
Solution Approach 2:
The patent employs dynamic mode coupled state change means that can rapidly switch between different spatial modes during measurement. This dynamic switching capability allows the system to measure multiple modes in succession without requiring static reconfiguration for each mode, significantly reducing the measurement time proportional to the square of the number of spatial modes
2Measurement precision
If transmittance is measured for each spatial mode using existing measurement devices, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent designs a universal measurement device where a single light receiver can detect multiple spatial modes by receiving light corresponding to different spatial modes at different measurement timings. This multi-functional approach eliminates the need for multiple specialized receivers or complex switching mechanisms, simplifying the overall device structure while maintaining the capability to measure all spatial modes
Solution Approach 2:
The patent introduces mode coupled state change means as an intermediary component that mediates between the light source and the light receiver. This intermediary dynamically controls the spatial mode of the light beam, allowing a single receiver to capture information from multiple modes sequentially, thereby reducing device complexity
3Productivity
If mode-dependent loss is not properly managed, then signal restoration efficiency deteriorates, but measurement and management become difficult
Solution Approach 1:
The patent implements a feedback mechanism where the measured mode-dependent loss information is used to optimize signal restoration processes. By continuously measuring MDL characteristics and using this data to adjust MIMO processing parameters, the system maintains high signal restoration efficiency even in the presence of mode coupling effects
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
Enables accurate and cost-effective measurement of mode-dependent loss in coupled multi-core optical fibers by suppressing errors caused by mode branching, thereby improving the efficiency of signal restoration in communication paths.
Implementation Method 1
The light source is optically coupled with an input end of an excitation optical fiber, and inputs light to the input end of the excitation optical fiber
Implementation Method 2
The light receiver detects a sum of powers of outputted light beams from a plurality of core end faces positioned on the output end of the measurement target optical fiber
Implementation Method 3
a coupled multi-core optical fiber (CMCF) in which waveguide modes are coupled between a plurality of cores
Implementation Method 4
The analysis unit analyzes variations in optical powers detected by the light receiver during a period in which the mode coupled state of the excitation optical fiber is changing
Data Source
AI summary
A mode-dependent loss measurement device measures a mode-dependent loss of a measurement target optical fiber including a coupled MCF. The device includes a light source, a light receiver, a mode coupled state changer, and an analysis unit. The light source inputs light to an input end of an excitation optical fiber including another coupled MCF. The light receiver detects a sum of powers of outputted light beams from a plurality of core end faces positioned on an output end of the measurement target optical fiber. The mode coupled state changer changes a mode coupled state of the excitation optical fiber. The analysis unit obtains a mode-dependent loss of the measurement target optical fiber from variations in optical powers detected by the light receiver.