Tapered Microstructured Optical Fiber for Supercontinuum Generation
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Solution Overview
Problem
Existing optical fiber tapering methods are limited in controllability and length, particularly for supercontinuum generation, as they are either post-processed and short or produced during drawing with uniform diameter control, making it difficult to achieve long, controllable tapers for efficient supercontinuum generation.
Innovation Solution
A tapered microstructured optical fiber is produced using a drawing tower with a capstan and heating device, allowing for controlled acceleration and deceleration to create long, controllable tapers with varying cross-sectional dimensions, enabling efficient supercontinuum generation by optimizing the taper profile and microstructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If optical fiber tapering is performed on a tapering station after drawing, then the fiber can be tapered and recoated, but the maximum length is limited to about 0.5 meters and the process is complex
Solution Approach 1:
The taper is created during the fiber drawing process itself, before the fiber is fully formed and coated. By incorporating the tapering action into the drawing process, the fiber is tapered while it is still being formed from the preform, eliminating the need for subsequent tapering stations and recoating operations.
Solution Approach 2:
The patent combines the tapering function with the fiber drawing process. The drawing tower, which normally produces uniform fibers, is modified to include mechanisms for creating tapers during drawing, merging two previously separate operations (drawing and tapering) into one integrated process.
2Length of stationary object
If optical fiber tapering is performed during the drawing process, then long tapers can be produced, but the capstan controls drawing speed to provide uniform fiber diameter, making short-distance taper control difficult
Solution Approach 1:
The patent introduces dynamic control mechanisms that allow the drawing speed and/or preform feeding speed to vary during the drawing process. This enables the creation of tapered sections with controlled profiles by dynamically adjusting the speeds, rather than maintaining constant speeds for uniform diameter.
Solution Approach 2:
The patent changes the drawing parameters (speeds, temperatures, or positional relationships) during the fiber drawing process to create tapers. By varying these parameters along the length of the fiber being drawn, controlled taper profiles can be achieved while maintaining long taper lengths.
3Stability of the object's composition
If the capstan provides uniform drawing speed, then fiber diameter is uniform, but taper controllability over short distances is poor
Solution Approach 1:
The patent segments the fiber drawing process into different zones: uniform diameter sections where the capstan maintains constant speed for stability, and tapered sections where speed variations are introduced for taper creation. This segmentation allows both uniformity where needed and taper control where required.
Solution Approach 2:
The patent applies different drawing conditions to different parts of the fiber. Uniform drawing conditions are applied in sections requiring consistent diameter, while varied drawing conditions are applied in sections requiring tapers. This local differentiation of drawing quality enables both uniformity and taper precision.
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
The approach allows for the generation of supercontinuum with enhanced power at the blue edge, improved spectral width, and efficient light propagation, overcoming the limitations of previous methods by enabling longer, more controllable tapers with optimized taper profiles and microstructures.
Implementation Method 1
heating device capable of heating at least a part of said fiber preform
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The invention relates to a tapered optical fiber and a method and drawing tower for producing such an optical fiber. The tapered optical fiber comprising a core region that is capable of guiding light along a longitudinal axis of said optical fiber and a cladding region surrounding said core region. The optical fiber comprises a tapered section arranged between a first longitudinal position and a second longitudinal position, said tapered section comprising a first taper section having a first length, L1, over which the optical fiber is tapered down to a taper waist, and a second taper section having a second length, L2, over which said optical fiber is tapered up.