The Research On Design Of RFoG Burst Mode Optical Transceiver

With the rapidly development of mobile Internet,people’s requirements for the network is also getting higher and higher.Using optical fiber lines fully,pursuing better service,meeting people’s business needs better and welcoming the arrival of triple play is a difficult task.The purpose of this paper is to study the design of one machine which consist of Optical receiver and emission.And apply it to the HFC network,it can achieve network bidirectional by combining the existing front-end device and customer’s equipment,without changing original operating mode and achieving FTTH’s technology solutions for network transformation.In this paper,the status of HFC network and the development of the problems encountered in the analysis and overview.At the same time according to the latest developments and research abroad,Describes the need for HFC networking products that meet the latest standards.Secondly,it summarizes the common parameters of the machine,and the related optical communication,RFo G,DOCSIS,modulation,filtering and WDM technology.Then analysis the overall structure of the machine,The design of the machine consists of downstream photoelectric conversion module,downstream RF amplification module,AGC circuit control module,filter circuit module,an upstream light emitting module,upstream RF detection circuit module,laser optical power control circuit module,an upstream RF amplification module and other circuit modules.At the same time design attenuation circuit,balanced circuit to improve the indicators,and design surge protection circuits to improve reliability.In order to achieve the burst mode of the machine.The main use of digital circuits and analog circuits separate layout.the filter circuit are design for improving the isolation of the uplink and downlink.In order to ensure the stability of burst level and turn-off level.While the choice of high-quality devices to build and a reasonable circuit to respond quickly to changes in the level.So as to shorten the turn-on delay and turn-off delay of the laser.So that conforms to the DOCSIS standard requirements for data distribution time slot characteristics.At the end of this paper,The main indicators of the machine and performance were tested.The test results are the C/N ratio of 52.2dB,the output level of 101.2dBV,reflection of16.1dB,CTB / CSO were 70 dB and 67 dB,the balance of 15 dB,the laser output power of2 mW,burst mode The turn-on level is 69 dBV,the turn-off level is 55 dBV,the turn-on delay is1.1? s,the turn-off delay is 1.4 ?s.Test results show that the burst mode one machine cancomplete the burst mode at the same time,to achieve a predetermined design performance indicators.it has been widely used in Suzhou’s TV station and highly appreciated in foreign markets.