D-Shaped Double-Clad Fluoride Fiber for Low-Loss Pump Absorption
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Solution Overview
Problem
Current optical fibers with double-clad fluoride face high transmission loss and low pump absorption efficiency due to contamination, complex preparation methods, and instability issues, limiting their application in mid-infrared laser generation and transmission.
Innovation Solution
A gain optical fiber with a D-shaped inner cladding and outer cladding made of fluoride glass materials, coated with a fluorinated ethylene propylene copolymer, prepared using a suction injection method and core insertion casting, which reduces interface losses and enhances pump light absorption efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a double crucible method is used to prepare gain optical fiber with double-clad fluoride, then the glass stability is maintained during preparation, but the preparation process becomes complex and the outer coating material is prone to heating and deformation under high-power laser pumps
Solution Approach 1:
The patent extracts the coating application step from the fiber drawing process itself, applying coating material to the preform before drawing rather than after. This simplifies the overall process by combining steps and eliminates the need for separate post-drawing coating operations, directly addressing the complexity issue while maintaining glass stability through controlled application conditions.
Solution Approach 2:
The patent applies the coating material to the preform before the fiber drawing process begins. This preliminary action ensures the coating is already in place and properly positioned before the high-temperature drawing occurs, preventing heating and deformation issues that would occur if coating were applied afterward to already-drawn fiber.
2Adaptability or versatility
If the drilling method is used to prepare optical fiber with double-clad fluoride, then optical fibers with any core cladding ratio and cross-section shape can be produced, but interface contamination occurs due to mechanical cold processing
Solution Approach 1:
The patent replaces mechanical drilling and cold processing methods with a casting-based approach where the cladding structure is formed by pouring molten glass around a preformed core. This substitution eliminates mechanical contact at the core-cladding interface, preventing contamination while maintaining the ability to produce various core-cladding ratios and cross-section shapes through mold design.
3Adaptability or versatility
If the extrusion method is used to prepare optical fiber with double-clad fluoride, then optical fibers with any core cladding ratio and cross-section shape can be prepared, but the preparation cost increases due to disposable ceramic molds and secondary heating causes glass crystallization
Solution Approach 1:
The patent changes the temperature parameter profile during the casting process, maintaining temperatures below the crystallization point throughout preform fabrication. By controlling the thermal parameters to stay within the glass transition range without exceeding crystallization thresholds, the method eliminates the need for costly disposable ceramic molds and secondary heating steps, reducing preparation costs while maintaining geometric flexibility.
4Shape
If the rotating tube method is used to prepare optical fiber with double-clad fluoride, then the outer cladding can be formed by rotation, but air gaps remain between outer cladding and inner cladding causing high interface loss
Solution Approach 1:
The patent introduces a molten glass intermediary that fills the space between the rotating outer cladding tube and the inner cladding core. This liquid glass mediator flows into and eliminates air gaps, creating direct optical contact between layers. Once solidified, this eliminates interface losses while preserving the rotational forming capability for creating the outer cladding shape.
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 solution achieves low transmission loss, high pump absorption efficiency, and improved mechanical strength, making the optical fiber suitable for mid-infrared laser applications with a simpler and cost-effective preparation process.
Implementation Method 1
The fiber core and inner cladding structure are prepared by a suction injection method
Implementation Method 2
the outer cladding is prepared by a core insertion casting method to form an optical fiber preform
Implementation Method 3
coated with a fluorinated ethylene propylene copolymer
Data Source
AI summary
An optical fiber with a double-clad fluoride with low loss and high pump absorption efficiency, and its preparation method are provided. The gain optical fiber with the double-clad fluoride includes a fiber core, a D-shaped inner cladding, an outer cladding, and a polymer coating, wherein the fiber core, the inner cladding, and the outer cladding are all fluoride glass materials, and the polymer coating is a fluorinated ethylene propylene copolymer. The fiber core and inner cladding structure are prepared by a suction injection method, and the inner cladding is polished into a D-shaped structure, and the outer cladding is prepared by a core insertion casting method to form an optical fiber preform with D-shaped double-clad fluoride and draw an optical fiber.