Optical Fiber Amplifier Multi-Core Connection Loss Reduction
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Solution Overview
Problem
Existing optical fiber amplifiers face challenges in reducing connection loss when applied to multi-core fibers (MCFs), as the core diameter expansion process used in single core fibers is difficult to apply uniformly to MCFs with multiple cores.
Innovation Solution
The optical fiber amplifier design includes a spatial optical system with lenses and wavelength division multiplexing filters to connect multiple cores, ensuring that the mode field diameters and core pitches of the first and second optical fibers are within specific ratios, allowing for effective optical connection and amplification across differing fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If core diameter expansion through dopant diffusion is applied to single core fibers, then connection loss is reduced, but the method cannot be uniformly applied to multi-core fibers
Solution Approach 1:
The patent applies segmentation by treating each core in the multi-core fiber system independently. The spatial optical system establishes separate optical paths for signal light and excitation light, with each path having its own coupling conditions. This allows the connection loss reduction technique to be applied to each core individually while maintaining the overall multi-core fiber structure and functionality.
2Loss of energy
If spatial optical system with lenses is introduced to match mode field diameters, then optical connection efficiency is enhanced, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a spatial optical system that simultaneously handles both signal light coupling and excitation light coupling functions. The system uses the same lens arrangement and coupling principles for both optical paths, allowing a single structural design to achieve multiple functions and reducing overall system complexity despite the presence of multiple components.
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 mitigates connection loss and enhances optical connection efficiency between fibers with different mode field diameters, enabling efficient signal amplification in multi-core fiber systems while simplifying the structure and operation.
Implementation Method 1
The first optical member is configured to cause the optical signal output from the first optical fiber to enter the second optical fiber through transmission or reflection
Implementation Method 2
The first optical member is configured to cause the optical signal output from the first optical fiber to enter the second optical fiber through transmission or reflection
Implementation Method 3
The second optical member is configured to cause the excitation light output from the third optical fiber to enter the second optical fiber through reflection or transmission
Implementation Method 4
The second optical member is configured to cause the excitation light output from the third optical fiber to enter the second optical fiber through reflection or transmission
Implementation Method 5
The first lens is arranged to face an outputting surface of the first optical fiber... The second lens has a focal distance f2S at the wavelength of the optical signal
Implementation Method 6
A rare-earth element is doped to the second optical fiber. The second optical fiber is configured to amplify the optical signal propagating therein by excitation light
Data Source
AI summary
An optical fiber amplifier comprising first, second and third optical fibers, and first, second and third lenses, is disclosed. First cores of the first optical fiber and second cores of the second optical fiber have homothetic arrangement each other in the arrangement of outer cores. The first core has a mode field diameter MFD1S when transmitting an optical signal and a core pitch P1, and the first lens has a focal distance f1S at the wavelength of the optical signal. The second core has a mode field diameter MFD2S when transmitting the optical signal and a core pitch P2, and the second lens has a focal distance f2S at the wavelength. The MFD1S of each first core is within ±25% of MFD2S×(P1/P2) of the corresponding second core, and the MFD1S of each first core is within ±25% of MFD2S×(f1S/f2S) of the corresponding second core.