Select an appropriate optical fiber connection method to save FTTP costs

Today, the competition in the access network market is fierce. When deploying fiber-to-Building (FTTP) networks, it is usually difficult but necessary to make a budget early. This is because business providers should not only consider the initial installation fee, but also the unexpected business operation and maintenance costs. A large number of cost budget models prove that in the design and construction stages, the correct method for connecting FTTP networks in different segments is more accurate, the use of enhanced connectors during the entire life of the network can bring more significant economic benefits than on-site welding.

Although the FTTP architecture varies during design, they have basic similarities. The cost model shows that reducing the number of weld points, welding technicians, and welding operators will significantly reduce network costs. In addition, the new architecture introduces a multi-Optical Fiber service terminal (MST) and a set of fused points, further reducing the initial construction cost (see figure ). Finally, when a technician is responsible for maintenance, repair, failure, and service activation, the two basic areas of the FTTP network-the interface between the feeder segment and the distribution equipment, the interface between the distribution device and the home cable of the outdoor device-using connectors will make access easy and reduce costs.

Early FTTP network setup personnel need to weld each joint point from the Central Bureau to the user network. The reason is that the lack of confidence in the cost and reliability of the connector in the outdoor environment. For example, when the outdoor temperature is close to-40 °F, the plastic used in the connector shrinks more than the optical fiber, which leads to microbending of the optical fiber and causes insertion loss.

In recent years, the reliability of connectors and Cable Accessories has been greatly improved. Research shows that new optical cables and accessories can be used in most harsh environments. The component is made of Low-shrinkage plastic and the rest space is filled with adhesive. Today, components are designed at the plant to compensate for temperature changes to meet the requirements of Telcordia GR-326Issue 3 standards.

The latest connectors and Cable Accessories specially designed for outdoor devices have been prepared, and network setup personnel can now use connectors that can be placed at any connection point in the network, instead of splicing.

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The figure shows that using multi-Optical Fiber service terminals in key locations of a typical FTTX network can reduce the number of weld points, which will reduce the working hours and costs of the fusion worker.

Weld and connector

In the network, where is the most meaningful use of connectors? In order to simplify troubleshooting, facilitate reconfiguration, and enable services, the use of connectors in the Central Bureau is already a standard practice. This is still available in today's FTTP networks-using connectors at critical intersections of outdoor devices gives the network better flexibility. It also saves more costs than using the fusion method.

The typical network elements of the FTTP Optical Distribution Network include the feeder optical cables and optical splitters of the optical fiber distribution terminal (FDT ).
It is also located in FDT. The allocated optical fiber cables are connected from the FDT to the multi-Optical Fiber service terminal, and the home optical fiber cables are also connected here. Next, the optical fiber cables are connected from the MST to the optical network terminal (ONT) in each user building ).

In this part of the network, optical fiber cables need to be connected in many locations. In many optical connection points, such as feeders and distribution optical cables, the optical fiber can be simply fused. However, the use of optical connectors for key joint points in FDT, MST, and ONT gives better flexibility.

It is better to use connectors at any joint point in the network. To test, activate, and reconfigure services, technicians need to access the network frequently. Using connectors in these locations can reduce operation costs and save time compared to splicing. To test the connection, you must first consider using connectors instead of splices.

Failure isolation of FTTP networks poses two major challenges to technicians. First, once the OTDR tracking signal encounters a splitter in the fdt, it is difficult to transmit the signal from CO. Therefore, the technician must access the network at the FDT. If all FDT connection points have been fused, the weld line needs to be opened by the welder. After tracking, the splitter must be refused to the allocated optical fiber. This process is time-consuming and costly, and there are also risks of more problems in the process of operating the optical fiber.

The connector is used in the optical splitter output port to facilitate the testing of all distributed optical cables. We only need to find out the allocation optical fiber that may be faulty, disconnect the output pigtails on the splitter, and then plug in the OTDR transmit optical fiber. Once the test is completed, the OTDR transmitting optical cable is disconnected from the allocated Optical Fiber port and re-connected to the output pigtails of the splitter. In this way, the optical fiber does not need to be damaged, and fusion is not required. In addition, because all optical fiber output from the splitter is connected to the plug-in board, the optical fiber will not be damaged due to the addition of a coat.
In addition, FDT is a point in the network that has a great impact on the Rapid Isolation of faults. Testing from the user's ONT point is not easy to implement due to user location or schedule. However, if the splitter is regarded as a distribution box, the optical fiber cables of many users can be tested. Also, using connectors in place of splitters can simplify the testing process and reduce costs.

Further reduce welding costs

Using connectors in the MST can also significantly reduce costs and reduce the number of weld technicians. This is a relatively new architecture: the pre-apex MST has 12 optical fibers, each extending from a centralized fusion point to each MST. This architecture avoids the use of heavy optical fiber cables and the access to these optical cables from many locations.

Although the number of weld points is roughly the same, all the weld points are carried out in one place, which further reduces the total cost of welding in the FTTP network. Most of the costs of fusion are generated during the setup period. Centralized fusion in one place allows the technician to complete the setup at a time and weld up to 12 optical fibers.

In addition, there is no need to splice in the MST, so that the connection box and The binning box for storing the optical fiber terminal can be very small. From the perspective of materials and installation, this is also a major advantage. Most municipal bureaus want to use small, lightweight cable boxes and small Connection boxes. Therefore, it makes sense to use MST for network planning.

A cost model with 192 users shows that, compared with traditional architectures, FTTP networks using MST and connectors can reduce cable costs by 85%, as shown in the table ). This is mainly because the cost of optical cables is now included in the terminal cost. At the same time, the cost of fiber pulling is reduced by about 25%, and the cost of fusion is reduced by about 70%. In fact, although MST increases the cost of the business terminal, the total cost per household is significantly less than the network wiring by about 19%.

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Reduce Household fees

In the home-to-home Optical Cable Section of the network, the use of connectors between the business terminal and the ONT has a cost advantage. Factory pre-tip mounted household optical fiber cables can be used to connect business terminals to each subscribers. These optical cables are connected to each end first and cut to a specific length, which greatly reduces the installation time and cost of the home cable. The cost model shows that the total cost can be reduced by at least 25% if the factory pre-exceeded home cable is used instead of home cable.

Although some people say that the connector will cause more light loss and require more spare connectors, we can draw a conclusion through the comparison in the cost model: using connectors reduces the total installation fee for FTTP networks. Whether to use the weld or connector at any point of FTTP depends on the cost. Correct selection can save time and money, and reduce faults during network deployment and operation. Using connectors or splices is not the problem. Whether using a connector network or a fused network, ensuring network performance, reliability, and flexibility is the most important thing.