The CATV Video Transmission On Passive Optical Network (PON) System

The rapid development of access network these years in Chinahas been known to all. Passive Optical Network (PON) technologyseems to become the major access trends of FTTx under large-scaleapplication of PON equipments and dramatically decrease of ASICchip cost and large volume construction of fiber network.Together with prompt development of internet, the requirement toaccess network bandwidth from customer becomes more and moreurgently, which results in a bottleneck problem in traditional accessnetwork. And new access network technology to take place oftraditional one is a hot topic currently. Therefore IEEE set up Ethernetin the first Mile Study group at the end of 2000, which is dedicated todevelop a new technical standard—Ethernet PON or Ethernet overPON. Generally EPON carries Ethernet protocol, and PONtopological structure, which is also studied and discussed hotly, anddraft has been prepared. EPON will become a important role in IEEE802.3 protocol in the future because of its great advantage in broadbandaccess network. In fact, fiber optical CATV transmission system is based on onetransmitter to drive multi optical receivers, which is quite similar to theoptical transmission structure of PON system. 1310/1490/1550 tripleplay demonstration was set up on 2002 OFC in the Unite States, That is,1550nm wavelength is used for forward CATV transmission, 1310nmwavelength is used for return path transmission of terminal user and1490nm wavelength is used for forward data transmission, meanwhilethe triple play is converged to a single fiber through WDMtechnology. The CATV video transmission on PON system wasemphatically discussed and studied in this paper, especially includingof the transmission performance, such as CNR(Carrier to Noise),CSO(Composite of the second order), and CTB(Composite of the thirdbeat). Various experiments were done to test different performance ofCATV transmission system, via adopting 1550nm external modulationoptical transmitter plus 10km fiber, optical attenuator and opticalreceivers, and 1550nm external modulation optical transmitter plusEDFA , WDM with 20km fiber and optical attenuator, optical receivers.And we also change the input power of optical receiver to judge the testresult of experiment. The result indicates that 1550nm CATVtransmission performance on PON system meets GY/T 143-2000professional criteria, which is the specifications and methods ofmeasurement on AM laser optical transmitter and receiver used inCATV system, and was set up by The State Broadcast, Film, and TVBureau, and we get almost the same test result compared to 1550nmCATV transmission system independently in single fiber. Therefore itconcludes that 1550nm CATV transmission, even triple plays can becompletely set up in PON system. High requirements to isolation of key passive component--WDMand the piece-connection block were issued in this paper during theexperiment. Theoretically, it points out the isolation requirements ofWDM between each wavelength of 1310/1490/1550nm. The WDM hasbeen experimentally tested by the great support of our vendors and itmeets the demand of design and it can fulfill video transmissiondemand in single fiber system. Currently it has been applied widely inthe market. Through the above experiments , the realization of CATVvideo transmission in single fiber system on PON means the tripleplay of data ,voice and video transmission in single fiber, whichprovides us a better solution opportunity for FTTC(Fiber to the curb),FTTB(Fiber to the building),and even FTTH(Fiber to the home). The topic of triple play in single fiber is quite newly, which coversdigital and analog CATV transmission system, data, voice opticaltransmission system, PON system, and fiber access network, thereforeit is also quite difficult to describe completely in short words. In themeantime, triple play in single fiber will play a big role in constructionof future FTTx network in China, even in all of the world. And it isespecially meaningful for the Broadcast and TV department in China torealize rapidly data service for its customers through PON system isadopted over its HFC 1550nm CATV system on single fiber, On theother hand, it also can help telecommunication department to promptlydevelop and occupy CATV business through adopting 1550nm CATVtransmission on PON system via single fiber. Generally, 1550nm CATV video transmission on PON throughsingle fiber—one of triple play solution, will be a potential trend ofbroadband access network, especially in new zone construction in...