Research On Orthogonal Frequency Division Multiplexing-passive Optical Network With Low-cost Colorless ONU

Passive optical network (PON) is recognized as one of the most promising solution forthe first mile. Many network architectures are proposed to extend access capacity anddistance, with the rapid growth of the bandwidth demands.With growing of user’s demand for bandwidth, more and more flow of the accessnetwork and multi-service support is needed. TDM-PON is hard to reach more high speed,and OFDM-PON becomes potential for the next-generation optical access network as a verystrong contender.Orthogonal frequency division multiplexing (OFDM) has become one of the researchfocuses in the field of optical communications in recent years as an advanced multi-carriermodulation technique, due to the advantages, such as high spectral efficiency and thedispersion tolerance.The specific sub-carriers in OFDM provide finer bandwidth allocation granularity inOFDM-PON to reach the flexible bandwidth allocation need of multi-users and multi-services,the technique is compatible with the TDM-PON, also supports Isomerism applications.An OFDM-PON scheme upstream with colorless ONU is proposed in this thesis. Thecolorless ONU is based on a tunable DFB integrated module which wavelength is controlledby temperature. Optical carrier of each ONU has different wavelength and each ONUoccupies different subcarrier. OFDM signal is intensity-modulated to generate an uplinksignal in each ONU. OLT have only one receiver unit to direct detect the signal.In the first, we introduced the research background, then analyzed the principle and ofOFDM and the function of each part in the mathematical model. We also elaborated thedevelopment of next-generation passive optical networks, further the upstream scheme basedon OFDM-PON with colorless ONU is proposed and its mathematical model is presented.The feasibility of the scheme is verified by OptiSystem software, and system performance isalso tested. Moreover, we set up an experimental platform for the scheme. OFDM signal isproduced and recovered via off-line MATLAB, verification and analysis of the introducedscheme is also presented.