Tether Cable Fiber Constraint for Splice Strain Protection
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Solution Overview
Problem
The variation in cable assembly structure due to different tether cable lengths leads to manufacturing inefficiencies and design challenges in determining the uniform excess optical fiber length for storage in network access point cavities, affecting the distribution and protection of optical fiber splices.
Innovation Solution
A fiber optic cable assembly design where the optical fiber of the tether cable is tightly constrained within its jacket, allowing a standardized cavity geometry and network access point structure, with a portion of the fiber extending into the cavity to be spliced with the distribution cable's fiber, thereby isolating the splice from strain and maintaining a consistent net length regardless of cable bending or stretching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of excess optical fiber length stored in the cavity is increased to compensate for stretching and bending of longer tether cables, then the splice is better protected from strain, but the cavity size and device complexity increase
Solution Approach 1:
The patent changes the physical state of the optical fiber from loose/coiled to tightly constrained, fundamentally altering how the fiber responds to cable movement. This parameter change allows the fiber to move with the cable rather than requiring excess length as cushioning, thereby protecting the splice without increasing cavity size.
Solution Approach 2:
Instead of allowing the fiber to move freely and using excess length to absorb movement, the patent inverts the approach by tightly constraining the fiber to move with the cable. This inversion eliminates the need for excess fiber length while maintaining splice protection.
2Reliability
If the cavity size is increased to accommodate more excess fiber length for longer tether cables, then fiber strain is reduced, but manufacturing efficiency decreases due to non-uniform assembly structure
Solution Approach 1:
The tightly constrained fiber configuration serves multiple functions simultaneously: it protects the splice from strain, eliminates the need for variable cavity sizes, and enables standardized manufacturing processes. This universal approach works for tether cables of any length without requiring design modifications.
Solution Approach 2:
By changing the constraint parameter of the fiber from loose to tight, the system achieves strain protection without requiring variable excess fiber length, thereby enabling uniform cavity dimensions and standardized manufacturing across all cable lengths.
3Reliability
If excess optical fiber length is stored in the cavity to accommodate tether cable stretching, then the splice is protected from strain, but the net length of fiber in the cavity varies with cable length
Solution Approach 1:
The patent changes the fiber constraint parameter from loose to tight, which fundamentally alters the fiber's response to cable movement. This ensures that the net length of fiber within the cavity remains stable and consistent regardless of tether cable length or movement, as the constrained fiber moves with the cable rather than requiring compensatory excess length.
Data Source
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Figure 4~5
AI summary
A cable assembly includes a distribution cable, a tether cable, and a network access point (NAP) assembly having a cavity defined therein. The distribution cable includes optical fibers and the tether cable includes an optical fiber. The optical fiber of the tether cable is tightly constrained within the tether cable and portion thereof extends from the tether cable into the cavity of the NAP assembly and is spliced to a portion of one of the optical fibers of the distribution cable extending into the cavity of the NAP assembly from a side of the distribution cable. The splice is positioned in the cavity. Tight constraint of the optical fiber of the tether cable within the tether cable limits transmission of fiber movement to the portion of the optical fiber of the tether cable extending into the cavity of the NAP assembly, thereby protecting the splice.