Research On Transceiver For Wideband Access Network

Contrasts to the rapid development of the backbone, the construction speed of accessnetwork is fairly slow. It causes the bottleneck for the access network in the next developmentstep. Obviously, it is inevitable to broaden the band of access network. Access mode can beclassified as xDSL,HFC Cable Modem,wireless and fiber access. No matter which way beselected, transceiver module play the key role in the whole procedure. In commonapplications, access transporting velocities is 155Mbps or 1.25Gbps. In this thesis, 155Mbps,155Mbps Bi-director and 1.25Gbps transceiver modules are researched, manufactured andmarketed. In this study, coaxial coupling configuration is adopted in LD & PINTIA. The theory forcoupling between laser and fiber is analyzed in detail, including coupling efficiency andoptical power jitter. Furthermore, mechanical designs for the coaxial coupling configurationsof LD and PINTIA are accomplished. The 1×9 standard configuration of transceiver moduleshell is mentioned, complying with multiple sources agreement. The mechanical design oftransceiver module shell is given then. In addition, transmission lines theory is carefully discussed. The tele-equation andcharacteristic impedance equation are deduced. After this, transmission lines terminations andanti-interference rules are introduced. Referring to those mentioned above, a terminationimpedance network between two PECL interfaces is analyzed and calculated. Based on the theories related, the schematic circuit diagram and PCB diagram are given.Considering the temperature performance of LD, a linearization method using NTCthermistor resistance network is achieved to compensate for threshold and extinction ratio ofthe LD. The experimental data show the excellent compensation results. Finally, an experimental plan is lay out. The test on the 1.25G transceiver module iscompleted. The results of the transmitter parameters are presented. The extinction ratio is14.2dB. The transmission eye diagram is wild, vivid and fine. These parameters strictly matchthe standard test mask of the Gbit Ethernet. And the receiver parameters are mentioned asfollows. The receiver sensitivity is –30.0dBm. There are no overshoot, no double lines and noresonance in the receiving electronic eye diagram. The RMS-jitter is only 11.38ps. All resultsshow the perfect performance of the transceiver module.