Construction methods of double-core covered optical cables. In the FTTX project, covered optical cables are used on a large scale. Two splicing methods are mainly used: one is the optical cable cold splicing technology (physical splicing) based on cold splices; The first is hot melt technology using a welding machine as a tool.
a. Cold splicing technology Cold splicing technology: Optical fiber cold splicing is used when two pigtails are butted. Its main internal component is a precision V-shaped groove, which is used after the two pigtails are spliced. Cold connector is used to connect two pigtails.
It is simpler and faster to operate and saves time than using a fusion splicer.
On the surface, the cold splicing operation is simple and fast, and saves time compared to the hot fusion of the fusion splicer. However, the cold splicing technology is also mainly used in emergency applications after the optical cable communication is interrupted.
There are obvious shortcomings in cold connection technology: (1) Cold connection loss is large.
Due to the use of physical splicing, the two optical fibers are completely spliced by V-shaped grooves and matching liquid. This loss is obviously greater than the hot-melt connection point.
In the FTTX project, although the line loss requirements are not as strict as those for trunk lines, large loss points are potential fault points.
(2) Short service life and high maintenance costs.
In cold joining technology, the role of matching fluid is very important.
Quoting data from operator customer statistics, imported matching fluids generally have a lifespan of about 3 years, while domestic matching fluids have a lifespan of only 1.5 to 2 years.
In this way, the cost of maintenance is increased.
And the cost of a cold joint is generally around 30 to 50 yuan (it can be disassembled and reused, but the accuracy of reuse after disassembly is greatly reduced, so the cold joint is nominally repeatable, but in reality They are only used once during the construction process), and the actual use and maintenance costs are high.
b. Hot melt technology 1. Small welding loss.
The two optical fibers are spliced using hot-fusion technology and in accordance with trunk line standards, which greatly reduces splicing loss.
2. Long service life and low maintenance cost.
Since the hot melt standards comply with the requirements for trunk line construction, the life of the general welding point will be similar to that of ordinary optical cables, and there is no problem with the life of a single point.
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