Theoretical And Experimental Study On Carrierless Amplitude And Phase Modulation Passive Optical Network

As the boost of the broadband internet service such as HD video,it becomes crucial to develop the super high capacity broadband internet access technique.Passive Optical Network(PON)has gained more and more attention for its high capacity,long distance reach,low cost and supportable for all types of service.As an advanced modulation technique,carrierless amplitude and phase modulation(CAP)has been proposed and applied in the copper cable communication for the first time.As a variant of Quadrature amplitude modulation(QAM),CAP can support the multilevel and multidimensional modulation by orthogonal waveform in time domain.Meanwhile,CAP is a simpler and lower cost scheme because it can be easily realized by low-cost transversal filters,which is different from QAM technique using sin/cos carrier.So it has high theoretical and practical value in analyzing the CAP technique in PON system.In this thesis,I gave a brief introduction to the CAP modulation and analyzed the difficulties in the CAP signals transmission within the fiber.Besides,I simulated and experimentally analyzed the application of CAP technique in the PON system.At last,several innovations have been achieved.In the process of CAP filter designing,the optimal CAP filter designed method optimization expression has been proposed by combining the multiband expression method and traditional minmax method.It improved the spectrum efficiency(SE)and transmission performance of CAP technique by theoretical analyzing and experimental verification.To explore the potential application of CAP technique,the feasibility of the application with CAP signals in PON system has been theoretical and experimental verified.It come to the conclusion that CAP technique has the obviously advantage of reducing cost and energy consuming in PON system by comparably verification.Based on the commercial time division multiplexing PON system,we proposed the hybrid multi-dimensional CAP and TDM technique in the PON system.Moreover,we gave a brief introduction to the optical line terminal(OLT),optical network unit(ONU)and the controlling processing for down-up link transmission,which laid a foundation for the CAP technique commercialization in PON system.As the traditional CAP technique has some drawbacks such as its sensitivity to time jitter,we combined the orthogonal frequency division multiplexing(OFDM)technique and CAP technique to recover the distortion of the CAP signals in the fiber by channel estimation method in OFDM.In this thesis,we experimentally verified the feasibility of using the hybrid technique in PON system by successfully demonstrating a 5Gb/s downlink system over 25 km single mode fiber(SMF).To take full advantage of the CAP technique,we designed multi-dimensional CAP-PON architecture.Moreover,we experimentally verified the down-uplink transmission with intension-modulation and direct detection(IMDD)configuration.We theoretically analyzed the optical beat interference between ONUs in the uplink transmission,and the carrier-suppression and coherent receiver method has been vitiated via experiment.We also demonstrated the feasibility of CAP technique in the long reach coherent PON system,as well as the feasibility of the digital signal processing in mitigation of dispersion and phase noise.Besides the orthogonal CAP technique above,the non-orthogonal CAP technique has been expandly explored.We explored the performance of the non-orthogonal CAP filters.With the broader orthogonal limitation in CAP filters,we compressed the bandwidth of CAP filters.However,the non-orthogonal will also introduced interference between each dimensional signal.In this thesis,we also proposed a novel interference cancellation algorithm(ICCA)to mitigate the inter symbol interference(ISI)and Cross Channel Interference(CCI).We increased the spectrum efficiency from 3.85bit/s/Hz to 4.35bit/s/Hz in the non-orthogonal CAP-PON system with the proposed ICCA.