For solving the shortage of optical fiber resource in the construction of FTTH, making the best use of the bandwidth of optical fiber, enhancing the reliability of network, PON( Passive Optical Network) technology has been developed and adopted into construction of FTTH, and security network monitoring as well.

PON is Passive Optical Network. A PON includes an OLT(Optical Line Terminal) installed in the central control station, and a set of ONU(Optical Network Unit) installed in user’s occasions. Beyond these, there is an ODN(Optical Distribution Network) between OLT and ONU, ODN includes optical fibers and passive optical splitter or coupler, these are the major apparatuses in PON.

Benefits of PON

There is no any active components from center to user’s premises network in PON, passive optical components are inserted into network instead, they are also used to lead the transmitted traffic by splitting the power of light wavelength in the whole loop. Replacing with the passive optical components makes users free of supplying and maintaining for active components, which largely save costs for users. This benefits could be explained as a result of that passive optical splitter and coupler is only able to transmit and limit light, there is no need to supply power or process information, and the average time between faults is not restricted any more, accordingly, costs for maintenance could decrease.

As a conclusion, the advantages of PON technology could be seen from below aspects:

1. Optical fiber access network is a solution that most adapt to future development, especially PON technology has been proved to be a quite economic and effective way for the current comprehensive bandwidth access.

2. As PON technology adopted, the whole optical distribution network is passive, which makes the network small and easy. Compared with copper cable network, PON can reduce the costs of maintaining and operating, and thoroughly avoid the interference of electromagnetism and lightning.

3. There is no need to supply power for passive ONU of PON, which not only avoid the a series of problem from power supply, and the reliability is also superior to active components.

4. Low investment cost for whole optical network. Because passive components are used, and share fiber optical transmission medium.

5. PON is transparent for transmitting system to some extent, which makes it easier to upgrade.

PON technology is recognized by pubic as the primary solution for FTTH. PON technology adopts point to point topological structure, its upstream and downstream transmit data respectively by TDM and TDMA. The maximum distance between OLT and ONU is up to 20km, transmission rate is bidirectional symmetric 1Gbps, maximum splitting ratio could support 1:32 or higher, single level splitting or multiple level splitting is available.

PON technology is able to effectively solve the limitation of bandwidth and distance of network monitor. OLT equipment deploys in the user’s end, adopting multiple light distribution to accomplish flexible deployment. ONU plus network camera work as a terminal combination, and ONU could be PoE switch with PON function. In this loop, data is sent to monitor room and storage server of users, so it’s not difficult to monitor in monitor room, at the same time, video data is sent to storage server so as to collect evidence afterwards.

Conclusion

With the rapid development of optical fiber network, PON technology takes an increasingly important mission to be put into extensive use. For the remote video monitor and control system, PON technology is adopted to work out lots of issues like shortage of optical fiber resource, intensive and complex city monitoring points and so on, which gives many outstanding advantages to optical fiber resource, video quality and reliable and others, and provides the best network solution for the development of remote video monitor and control.