Research Of Burst Mode Optical Transmitter Module For APON

We are now building broadband communication network on a large scale within and outside the country, and access network is known as the last mile of highway of information. Backbone network has been a broadband optical network of digital, while access network developed very slowly, and technically dropped behind, which has become the bottleneck of the complete network. Although conventional copper access technology have improved greatly, such as DDN, ISDN, ADSL, they still can't meet the growing demand of various communication services because of their technical disadvantages. Therefore , it is urgent to build a digital intelligent broadband access network. Many advantages make optical fiber suitable used as transmission medium of high-rate broadband services, such as broad transmission band , large capacity, low loss, strong immunity to interference etc. Among optical access network, passive optical network (PON) is paid more attention throughout the world. It offers easily upgraded and low cost of lay, operation and maintenance. Especially passive optical network based on ATM (ATM-PON) integrates the capability of supporting multiple Qos services with ATM and transparent transmission with PON. It is a future-proof solution of broadband access network and even finally FTTH implement in the future.The key components of APON system is burst-mode up-stream transmitters and receivers for O/E transform. During the period of up-stream transmission, the optical signals emitted from ONU reach office center by fiber cable with different length. Amplitude and phase of signals received are different. Intervals between every framing signal are very short of only 30 bit, i.e. 192ns (155.52Mb/s), the power difference of two signals can arrive at 15dB(G.983 suggestions). So special burst-mode transmitters and receivers should be adopted at up-stream transmission.The main purpose of the thesis is to research 155Mb/s burst-modetransmitter applicable for APON system. With peak-detection automatic power control technology, laser diode is successfully used as light source to emit burst optical signals.The thesis consists of seven chapters. In the first chapter, the development of broadband access technology is analyzed and the main task of research is introduced. In the second chapter, we analyzed the advantages and disadvantages of all kinds of access technology, and mainly introduced APON technology. In the third chapter, the constitute, function and parameter of burst mode transmitter are particularly analyzed. In the fourth chapter, the design scheme of burst mode transmitter is discussed, including the selection of light source and laser driver IC. In the fifth chapter, the circuit design and solution of difficulties are carefully presented. In the sixth chapter, the test process is presented and test result is analyzed. The seventh chapter is a summarization of the whole thesis.