What Scenarios are ODN Unequal Scores Applicable to?

1 unequal score optical adaptation scenario analysis

Traditional unequal score optical ODN introduction of fiber optic lines usually use a tree network structure, each splitter box is equivalent to the "leaves", generally assigned 2 cores (a master and a standby), the structure can be adapted to a variety of scenarios of access needs.

ODN if unequal score optical, single-core fiber optic cable can be used to cascade the splitter box down the cable route to form a single chain structure, as shown in Figure 2. However, when the fiber optic cable routing more branches, branch routing length is long, the single chain structure will be due to the fiber optic link routing detour and lead to an exponential increase in the length of the link, which increases the project cost and reduces the security of the link.

In order to reduce the routing detour of the fiber optic link, the ODN network with unequal score of optical ODN network can use dual-link and multi-link network. Fiber optic cable routing at the end of the non-branching segments using single-core fiber optic cable, branching segments using ordinary fiber optic cable, dual-chain 1 × 2 or multi-chain 1 × 4 optical splitter centrally set up in the junction box / splitter box.

The actual ODN introduction of fiber optic cable lines, cable routing branching is very complex, optical splitter settings and connection relationships will be more complex, whether for engineering design, construction, or ODN maintenance have brought great challenges. Therefore, when ODN introduces more fiber optic cable route branches, ODN is not suitable for unequal score optical.

Unequal score is suitable for use in scenarios where the fiber optic cable routes are chained. Since unequal score optical usually uses single-core fiber optic cables, and the traditional equal score optical ODN is set up in the splitter box with reserved cores, unequal score optical is especially suitable for the scenario where the splitter box in the original line continues to extend to the end of the line.

2 Unequal Score Optical ODN Networking

According to the distribution of fiber optic cable routes in the branch chain and the number of splitter boxes connected to each fiber optic cable chain, unequal scores of optical ODN is appropriate to use dual-chain or single-chain networking. When 4 to 6 splitter boxes are connected in series on the fiber optic cable chain, ODN should adopt single-chain networking; when 2 to 3 splitter boxes are connected in series, ODN should adopt double-chain networking.

3 and equal parts of the optical investment comparison

In the original cable can be depreciated spare fiber core, the use of unequal score of optical investment can be reduced a lot, the longer the length of the depreciated cable core, the more the investment is reduced. As the number of cable cores used for unequal score optical is much lower than that of equal score optical, even if the length of the cable is the same, the ODN cost of unequal score optical is only about 89% of that of equal score optical.

4 Equal score of other characteristics of optical

In addition to the differences in network structure and investment, the ODN of unequal score optical and equal score optical have the following differences.

(1) Low security. Because of the chain-type structure, any failure of the ODN link will affect the users below the point of failure.

(2) Easy management. Since the splitter produces about 2.0 dB of insertion loss per cascade, the connection relationship between the splitter box and the subscriber in the ODN link can be seen from the optical power received by the subscriber ONU. In addition, not equal to the score of light in the distribution of optical intersection into the end of the cable core is often only equal to the score of 10% to 20% of the optical, fiber management is also much less difficult.

(3) construction difficulty. Line often involves only single-core cable, cable only in the splitter box at the end of the need to be connected, the line and even the cable joints are not.

(4) poor capacity expansion. Equal to the score of each splitter box is usually reserved for expansion of 1 core; and unequal to the score of the optical expansion capacity is very limited, only in the link when the optical power has a certain surplus, by replacing the 1 × 5 splitter into 1 × 9 or in the link to increase the splitter for expansion.

(5) Poor service convergence capability. Equal score optical ODN has more fiber optic cable cores, and can integrate wireless pre-transmission services, data lines and other services; while unequal score optical ODN often uses single-core fiber optic cables, and can only access PON services.

6 unequal score optical application recommendations

In summary, in the need to access wireless, data line, home broadband and other services, or fiber optic cable routing more branches of the scene is not suitable for unequal score optical.

Unequal score is suitable for optical cable chain network, user business with PON access, access business security requirements are not high scenarios, especially suitable for the use of the existing splitter box of the remaining fiber core to the end of the extension of the situation.

Currently, unequal score optical mainly use single-core fiber optic cable, resulting in lower link security, difficult to expand capacity, but also difficult to adapt to the fiber optic link of the local meander, the use of dual-core fiber optic cable may be a better choice.