Coupled-Core Optical Amplifier for Efficient Pump Light Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional amplification multi-core fibers (MCFs) face low utilization efficiency of pumping light due to inefficient coupling of pumping light to rare-earth-doped cores, leading to high costs and low reliability in optical amplifiers.
Innovation Solution
The optical amplifier employs a coupled-core multi-core fiber (CC-MCF) with a coupling MCF that optically connects pumping light sources to each core, enabling efficient power coupling and reducing the complexity of the device structure, utilizing silica glass cores and claddings with a high mode-coupling coefficient to enhance light overlap with rare-earth elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a pump core is used to couple pumping light to amplifier cores in conventional amplification MCF, then pumping light can be supplied to multiple cores, but the utilization efficiency of pumping light becomes low due to inefficient coupling
Solution Approach 1:
The patent merges the pump core and amplifier cores into a single multi-core fiber structure where multiple cores are closely spaced to enable direct mode coupling. This eliminates the need for separate pump cores and complex coupling systems, thereby improving pumping light utilization efficiency while reducing device complexity.
Solution Approach 2:
The patent introduces mode coupling as an intermediary mechanism to transfer pumping light between cores. By utilizing evanescent field coupling between closely spaced cores, the system achieves efficient light transfer without requiring complex optical components, thus improving energy utilization while maintaining simple device structure.
2Area of moving object
If the distance between adjacent cores is reduced to increase spatial density, then the spatial density of information transmission increases, but the differential mode delay (DMD) increases requiring more complex MIMO signal processing
Solution Approach 1:
The patent carefully optimizes the distance between adjacent cores to achieve a balance between spatial density and mode coupling strength. By controlling the inter-core distance within a specific range, the system maintains strong coupling for high spatial density while limiting DMD accumulation, thereby reducing the complexity of required MIMO signal processing.
Solution Approach 2:
The patent introduces dynamic elements such as twisting and bending of the fiber to randomly vary the coupling conditions along the propagation direction. This dynamic variation prevents coherent accumulation of DMD, effectively reducing the overall differential mode delay and simplifying signal processing requirements while maintaining high spatial density.
3Loss of time
If mode coupling between cores is increased to reduce differential mode delay, then DMD accumulation is reduced, but the complexity of coupling pumping light to each core increases
Solution Approach 1:
The patent combines multiple amplifier cores into a single closely-spaced array that shares a common pump source. The strong mode coupling between cores naturally distributes the pumping light to all cores simultaneously, eliminating the need for separate coupling systems for each core and reducing overall device complexity while maintaining low DMD.
Solution Approach 2:
The patent designs the multi-core fiber structure to serve multiple functions simultaneously: the same core arrangement that provides strong mode coupling for low DMD also enables efficient pumping light distribution to all cores. This universal design achieves both low differential mode delay and simple pumping light coupling without requiring separate optimization for each function.
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 configuration simplifies the structure, reduces costs, and increases the utilization efficiency of pumping light, resulting in a reliable and cost-effective optical amplifier with improved light amplification capabilities.
Implementation Method 1
The coupling MCF has a plurality of second cores 31b each extending along a second central axis and a second cladding 32b surrounding each of the plurality of second cores. Each of the plurality of second cores is comprised of silica glass and is optically connected to any one of the plurality of first cores. The second cladding is comprised of silica glass having a lower refractive index than that of the plurality of second cores. The coupling MCF has a mode-coupling coefficient of 1 [1/m] or more at a wavelength of 980 nm
Implementation Method 2
Each of the plurality of first cores is comprised of silica glass doped with a rare earth element. Each of the plurality of first cores is comprised of silica glass doped with a rare earth element. The pumping light source supplies pumping light with a wavelength of 980 nm to each of the plurality of first cores via the coupling MCF
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present embodiment relates to an optical amplifier and the like having a structure for enabling efficient use of pumping light while avoiding complication of a device structure. In such an optical amplifier, since pumping light from a pumping light source is supplied to each core of an amplification MCF, a coupling MCF in which adjacent cores form a coupled core is arranged between the amplification MCF and the pumping light source. The pumping light source is optically connected to a specific core of the coupling MCF, and pumping light is coupled from the specific core to remaining cores except the specific core in the coupling MCF before pumping light is supplied to each core of the amplification MCF. This enables coupling of pumping light between optically connected cores between the amplification MCF and the coupling MCF.