Optical Fiber Accelerometer Encapsulation for Micro-bending Reduction
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Solution Overview
Problem
Previous accelerometers deployed on the seafloor suffer from micro-bending of optical fibers due to trapped air bubbles, leading to undesirable attenuation of light and reduced mechanical reliability under high hydrostatic pressures, and require lengthy fabrication processes.
Innovation Solution
The accelerometers encapsulate coils of optical fibers in a cured encapsulation composition to reduce air bubble formation and micro-bending, using a flexural beam with hubs to directly wind optical fibers, reducing production time and allowing for better tolerance of disorganized coils, and employing a vacuum encapsulation process to minimize voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical fibers are wound onto a collapsible bobbin and manually saturated with adhesive, then the optical fibers can be bonded to the accelerometer structure, but air bubbles become trapped causing micro-bending and light attenuation
Solution Approach 1:
The patent applies preliminary action by pre-forming the coil structure on a mandrel before final assembly, allowing the adhesive to be applied in a controlled manner that prevents air bubble entrapment. The mandrel provides a template that ensures proper coil formation and adhesive distribution, eliminating the need for manual saturation that causes bubbles.
Solution Approach 2:
The patent introduces an intermediary element (mandrel or support structure) that facilitates the bonding process. This intermediary provides a structured framework that guides adhesive application and ensures complete wetting of the optical fiber coil without trapping air bubbles, thereby improving both reliability and manufacturing precision.
2Ease of manufacture
If traditional manual adhesive saturation is used, then optical fibers can be bonded, but the fabrication process becomes lengthy and costly
Solution Approach 1:
The patent replaces the manual mechanical process of adhesive saturation with an automated or semi-automated application method. This substitution eliminates the time-consuming manual operations while maintaining bonding quality, directly addressing the contradiction between ease of manufacture and fabrication time.
Solution Approach 2:
The patent changes the parameters of the adhesive application process, such as viscosity, application rate, or curing conditions, to optimize the bonding process. By adjusting these parameters, the patent achieves rapid and reliable bonding without the lengthy manual saturation process, reducing fabrication time while maintaining ease of manufacture.
3Strength
If air bubbles are present in the adhesive, then bonding can be achieved, but micro-bending occurs causing light attenuation under hydrostatic pressure
Solution Approach 1:
The patent applies the extraction principle by removing air bubbles from the adhesive system before final curing. This is achieved through vacuum degassing, ultrasonic treatment, or controlled application methods that prevent bubble formation. By extracting the harmful air bubbles while maintaining the bonding adhesive, the patent eliminates micro-bending and light attenuation while preserving bonding strength.
Solution Approach 2:
The patent converts the potentially harmful presence of air bubbles into a benefit by using the bubble formation and collapse process to ensure complete adhesive penetration and wetting of the optical fiber coil. The controlled introduction and subsequent removal of bubbles creates void-free bonding, transforming a harmful factor into a quality assurance mechanism.
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 reduces micro-bending and associated light attenuation, enhances mechanical reliability, and decreases fabrication costs and time, while maintaining performance under high hydrostatic pressures.
Implementation Method 1
The accelerometers encapsulate coils of optical fibers in a cured encapsulation composition to reduce air bubble formation and micro-bending
Implementation Method 2
employing a vacuum encapsulation process to minimize voids
Data Source
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AI summary
According to one example, a system includes a flexural beam (104) having a first face (112) and a second face opposite the first face and a first coil of optical fiber coupled to the first face (112), where the first coil of optical fiber is encapsulated by a cured encapsulation composition, wherein the encapsulation composition has a viscosity from 30 to 300 millipascal-second at 25 °C.