Multicore Fiber Grating for Selective Wavelength Add-Drop
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Solution Overview
Problem
Conventional multicore optical fibers lack the ability to effectively drop or add specific wavelength channels due to optical coupling among cores at all wavelengths, making it difficult to implement add-drop filters with low stability and high fabrication complexity.
Innovation Solution
A multicore optical fiber with an inner core and peripheral cores having different diameters and/or refractive indices, combined with an optical fiber grating that couples optical signals between cores at a resonance wavelength, allowing for selective mode coupling and wavelength management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional multicore optical fiber with identical cores is used, then optical coupling occurs at all wavelengths, but it becomes difficult to drop or add specific wavelength channels
Solution Approach 1:
The patent applies local quality by creating peripheral cores with different effective refractive indices compared to the inner core. This is achieved by varying the core diameters or refractive indices of specific cores at specific locations, enabling selective optical coupling only at desired wavelength channels while maintaining isolation at other wavelengths
Solution Approach 2:
The patent changes the physical parameters of the optical fiber cores, specifically the effective refractive indices of the peripheral cores relative to the inner core. By controlling the diameter and refractive index parameters, the patent enables wavelength-selective coupling through the optical fiber grating structure
2Adaptability or versatility
If add-drop filter based on Mach-Zehnder interferometer is used, then wavelength channel can be dropped or added, but stability is low and fabrication is difficult
Solution Approach 1:
The patent extracts the complex Mach-Zehnder interferometer structure and replaces it with a simpler integrated structure combining multicore optical fiber and optical fiber grating. This extraction eliminates the need for complex external components while maintaining the wavelength selection function, thereby improving stability and simplifying fabrication
Solution Approach 2:
The patent merges the wavelength selection function and the add-drop filter function into a single integrated structure using multicore optical fiber with optical fiber grating. This consolidation eliminates multiple separate components and their associated alignment requirements, leading to improved stability and easier fabrication
3Productivity
If cores sufficiently approach each other in conventional multicore optical fiber, then optical coupling occurs at all wavelengths, but selective wavelength channel management becomes difficult
Solution Approach 1:
The patent applies local quality by creating peripheral cores with different effective refractive indices compared to the inner core. This is achieved by varying the core diameters or refractive indices of specific cores at specific locations, enabling selective optical coupling only at desired wavelength channels while maintaining isolation at other wavelengths
Solution Approach 2:
The patent utilizes optical resonance (analogous to vibration in optical domain) through the optical fiber grating structure to achieve wavelength-selective coupling. The grating period and effective refractive index difference determine the resonance condition, enabling selective coupling at specific wavelength channels while maintaining efficient transmission at other wavelengths
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 efficient dropping or adding of specific wavelength channels with improved stability and simplified fabrication, suitable for optical communication networks and sensors, by controlling mode coupling through refractive index and diameter differences and optical fiber grating periods.
Implementation Method 1
an optical fiber grating formed at the multicore optical fiber to cause an optical signal to be coupled between different cores among the inner core and the at least one peripheral core
Implementation Method 2
optical coupling between propagation modes may occur among the cores at substantially all wavelengths
Implementation Method 3
an optical fiber grating formed at the multicore optical fiber to cause an optical signal to be coupled between different cores among the inner core and the at least one peripheral core
Data Source
AI summary
An optical element includes a multicore optical fiber, the multicore optical fiber including an inner core and at least one peripheral core arranged around the inner core and having an effective refractive index different from that of the inner core, and an optical fiber grating formed at the multicore optical fiber to cause an optical signal to be coupled between different cores among the inner core and the at least one peripheral core. The optical element allows a signal of a specific wavelength to be dropped added from an optical signal. Since the optical element may be fabricated easily, designed in a small size and mass-produced reproducibly at low costs, the optical element may be advantageously utilized for an optical communication network such as a wavelength division multiplexing network, an ultra-high speed optical communication system, an optical sensor system or the like.