Optical Fiber Tensioning During Base Heating
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Solution Overview
Problem
Existing optical modules face reliability issues due to excessive bending of optical fibers, which can lead to cracks and breakage, and insufficient bending can cause tensile stress from thermal expansion of the base, potentially breaking the fiber.
Innovation Solution
A method of manufacturing optical modules where the optical fiber is fixed to two points with tension applied while the base is heated to its upper limit temperature, ensuring compressive stress is maintained within the guaranteed temperature range to prevent excessive bending and tensile stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the optical fiber is allowed to bend excessively in the housing, then the fiber can accommodate thermal expansion of the base, but the fiber may develop cracks and break due to excessive bending stress
Solution Approach 1:
The patent applies a predetermined tension force to the optical fiber during assembly, changing the mechanical parameter (tension) to counteract the effects of thermal expansion. By pre-applying tension F that satisfies F ≥ A×E×(k1−k2)×(tbase−tmax), the fiber remains under compressive stress during thermal cycles, preventing excessive bending while accommodating base expansion.
Solution Approach 2:
The patent applies preliminary anti-action by pre-tensioning the optical fiber before thermal expansion occurs. The tension is applied in advance during assembly to create a pre-compressive stress state that counteracts the tensile stress that would otherwise develop during thermal expansion, preventing fiber breakage before it can occur.
2Reliability
If the optical fiber is kept straight with minimal bending, then the fiber avoids bending-induced cracks, but thermal expansion of the base creates tensile stress that may break the fiber
Solution Approach 1:
The patent changes the stress parameter by applying a predetermined tension force during assembly. This creates an initial compressive stress state in the fiber that counteracts the tensile stress generated during thermal expansion. The tension magnitude is specifically calculated to ensure the fiber remains under compression or zero stress throughout the operating temperature range.
Solution Approach 2:
The patent explicitly accounts for thermal expansion by using the coefficient of thermal expansion difference (k1−k2) between the base and fiber in the tension calculation. The predetermined tension is designed to compensate for the length change of the base during thermal cycles, ensuring the fiber accommodates base expansion without developing excessive tensile stress.
3Ease of operation
If the central axis of the pipe part and upper surface of the fiber mount are not flush, then the optical fiber can be routed through the housing, but the fiber experiences unnecessary bending that reduces reliability
Solution Approach 1:
The patent applies a predetermined tension force to the optical fiber that compensates for the geometric misalignment between the pipe part and fiber mount. This tension keeps the fiber straight or minimally bent despite the non-flush configuration, preventing bending-induced stress concentrations while maintaining the practical routing advantage of the misaligned structure.
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 method enhances the reliability of optical modules by preventing excessive bending and tensile stress, thereby reducing the risk of fiber breakage and cracks, ensuring the optical fiber remains linear and within a safe bending range.
Implementation Method 1
a base connected to the respective fixing portions has been heated to an upper limit or higher of guaranteed temperature of the optical module
Data Source
AI summary
A method of manufacturing an optical module 1 in which an optical fiber 10 is fixed to two fixing portions (a fiber mount 30 and a pipe part 51) includes a first fixing step P3 of fixing apart of the optical fiber 10 to the fiber mount 30, and a second fixing step P4 of applying tension by pulling the optical fiber 10 while a base 20 connected to the respective fixing portions has been heated to an upper limit or higher of guaranteed temperature of the optical module 1 and fixing the other part of the optical fiber 10 to the pipe part 51.