Optical Distribution Network (ODN) Splitting Method
As an important part of the optical access network, the Optical Distribution Network (ODN) is located between the Optical Line Terminal (OLT) and the Optical Network Unit (ONU)/Optical Network Terminal (ONT), and is mainly responsible for the transmission and distribution of optical signals. In the design and implementation of ODN, the choice of splitting method is crucial, which not only affects the performance and cost of the network, but also is related to the subsequent expansion and maintenance. This article will discuss in detail the two main splitting methods of ODN: primary splitting and secondary splitting.
Overview of ODN
ODN is a FTTH (Fiber To The Home) optical cable network based on passive optical network (PON) equipment. It uses passive optical devices such as optical cables, optical connectors, optical splitters, optical cross-connect boxes, etc. to provide optical transmission channels between OLT and ONU. The construction cost of ODN network is relatively high, but it has the advantages of simple structure, high reliability and low maintenance cost. ODN transmits the optical signal sent by OLT to each ONU/ONT through transmission media such as optical cable, and realizes reverse transmission at the same time.
Primary splitting method
The primary splitting method refers to the use of only one optical splitter for splitting in the entire ODN network, which is usually set at the optical intersection of the wiring. The advantage of this method is that the structure is relatively simple, the optical link attenuation is low, and it is suitable for areas with high user density. However, with the increase in the number of users, the primary splitting method may encounter bottlenecks when expanding capacity, because all users share the same optical splitter. Once the upper limit of the splitting ratio (such as the common 1:64) is reached, the entire network needs to be replanned.
In practical applications, the primary splitting method has a relatively low cost in the initial construction because only one splitter needs to be installed. However, in the later expansion, it may be necessary to add additional splitters or rewire, which increases complexity and cost. In addition, the primary splitting method also has certain inconveniences in network maintenance, especially when the user distribution is uneven, which may lead to insufficient optical power in some areas.
Secondary splitting method
The secondary splitting method is to add a splitter cascade on the basis of the primary splitting. The first-level splitter is usually set at the wiring optical intersection, and the second-level splitter is set at the fiber splitter box. This method can flexibly adapt to areas with different user densities. By adjusting the splitting ratio and number of splitters, more efficient resource utilization can be achieved.
The advantages of the secondary splitting method are its flexibility and scalability. When the network is expanded, only a new splitter needs to be added at the fiber splitter box without large-scale transformation of the entire network. In addition, due to the use of multi-level splitting, the attenuation of the optical link can be more effectively controlled to ensure that each user can obtain sufficient optical power. However, the cost of the secondary splitting method is relatively high in the initial construction because more splitters and optical cables need to be installed.
Selection of splitting method
When choosing a splitting method, it is necessary to comprehensively consider a variety of factors according to the actual situation. User density, geographical environment, pipeline resources, capacity of the original optical cable, distance between OLT and ONU, network security and reliability, economy, and operation management and maintainability are all important considerations.
User density: In areas with high user density, the primary splitting method may be more suitable because it can reduce the number of splitters and the cost of laying optical cables. In areas with low user density or uneven distribution, the secondary splitting method is more advantageous.
Capacity expansion demand: If there is a clear demand for capacity expansion in the future, the secondary splitting method may be more suitable because it can be more convenient to expand capacity.
Cost considerations: The primary splitting method has a lower cost in the initial construction, but the cost of later capacity expansion may be higher. The secondary splitting method is the opposite, with a higher initial construction cost, but a relatively low cost of later capacity expansion.
Network maintenance: The secondary splitting method may be more complicated in terms of network maintenance because more splitters and optical cables need to be managed. However, with the development of technology, the introduction of intelligent management systems can greatly reduce the difficulty of maintenance.
The splitting method of the optical distribution network (ODN) is an important factor affecting network performance, cost and maintenance. Primary splitting and secondary splitting each have their own advantages and disadvantages, and the choice of which method needs to be comprehensively considered according to the actual situation. With the continuous development of optical fiber communication technology, ODN networks are also constantly evolving and upgrading. In the future, with the introduction of intelligent management systems and the application of automated monitoring technology, the operational efficiency and maintenance costs of ODN networks will be further optimized and improved.
TFN F7 and RM7 OTDR models support splitters, with a maximum split ratio of 64 channels.If you are interested in TFN OTDR tester, please contact the TFN sales team:
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