Research And Design Of GPON Optical Modules Based On Three In One Chip

Along with the development of Mobile Internet, our society has step into dataconcentration time, and the communication field of domestic industry is going through alldigital period, which is coming with explosive growth in backbone capacity. In accessnetwork, traditional access such as xDSL is trasfering to FTTx access, which is mostconcerned by telecommunication specialists and telecom operators as one of the mostattractive solution of last mile fiber access. The performance of optical module is the mostimportant factor all operators and equipment suppliers are concern about. As the key linkof optical communication system and op-electronic devices, operators as well as equipmentsuppliers are requesting high and strict properties of optical modules.The article is mainly about design of GPON optical transceiver module of ONU basedonThree in One chip solution, which is integrated by LDdriver, Post limiting Amplifier aswell as MCU controller. The module solution is based on SFF encapsulation, comply withindustrial standard and CLASS C+performance requirement, fully consider the integrity ofoptical signal, and optimize in both hardware and software according to practicalrequirement.First of all, the article analyzes the current situation and development trend ofnowadays optical communication field, and then proposes the research objective andsignificance of this article. On theoretical aspect, the article introduces passive networkaccess technology, and describes the topology and working mode of GPON system byrealistic examples. What’s more, the article specifies the principle and internal structure ofthe emission part of optical module, as well as the working process and key points of thereceiving part. Meanwhile, the article researches not only the laser, but also its drivingprinciple, as well as theory of APC control theoryand MCU controller.Based on the specific research of the design of optical module of GPON ONU in thethesis, such as the main control chip, the boost circuit scheme, peripheral memory, opticaltransceiver device, as well as performance property, design method, structure and principle of each chips, the paper also mainly analyzes the problems when design a peripheralinterface hardware circuit, and wiring&laying issues when design PCB layout, which aremost concerned about the integrity of optical signal. As a module combined with digitaldiagnostic function and automatic parameter controlling, the paper also describes theprocesses of the design of embedded software function in details.Finally, the thesis researches the debugging processes of GPON ONU module, testsall the main parameter intensively, such as optical power, extinction ratio,eye diagram,receiving sensitivity and alarm values. Meanwhile, the author analyzes the test records andtest results, and it shows that all the parameters of optical module are fully satisfied withrelated standards which can prove that the article has certain significance in realisticapplication.