Theoretical And Experimental Studies On Key Technologies Of Soa-Based Optical Signal Processings In Next Generation Optical Access Networks

Optical access network is critical to "Broadband China" strategy. As the key enabling technologies of optical access networks, low cost passive optical network (PON) and radio over fiber (RoF) for broadband wireless access will be widely used in developing the "Broadband China" strategy.Thanks to the great potential bandwidth and good compatibility with the other access technologies, the colorless optical network unit (ONU) based WDM PON has been considered as a cost effective and reliable solution for deploying the next generation optical access network.The reflective semiconductor optical amplifier (RSOA) based colorless ONU has attracted a lot of attentions, because of its high operation wavelength region, low power consumption, high power efficiency, low cost, and easily to be integrated with other semiconductor optoelectronic devices.Meanwhile the RoF combining the flexibility of the wireless access technology and high capability of the fiber access technology has become a potential solution for the network convergence between optical and wireless access networks. Nevertheless, the generation of the mm-wave and optical frequency conversion remain as great challenges in RoF. The SOA based optical signal processing can provide beyong100Gbit/s signal processing speed, over20dB small gain and wide operation wavelength region. Consequently, the SOA based optical signal processing has been considered as one of the most promising solutions for the photonics mm-wave generation and frequency conversion in the next optical access network.In this dissertation, RSOA-assisted colorless ONUs and SOA assisted photonics mm-wave generation and frequency conversion are major research content. With the experimental platform and the simulation tool VPI transmisstion maker, several novel RSOA-assisted colorless ONUs and photonics mm-wave generation&frequency conversion with SOA four wave mixing (FWM) have been proposed and demonstrated. The main research achievements are summarized as follows:Firstly, based on the experimental tests of the RSOA, the numerical model applied to low bit rate signal modulation and narrow linewidth injected light is bulited and optimized. Quantitative analysis of the RSOA modulation character is given based on the tests. The numerical model and experimental tests is the foundation of the design of the RSOA based colorless ONU in the following research works.Secondly, the effect of the Rayleight backscattering (RB) in single fiber full-duplex RSOA based colorless ONU is analyzed. In addition, to suppress the crosstalk brought by the Rayleight backscattering, two kinds of RSOA assisted Interferometers (RSOA-MI and RSOA-DI) are proposed and verfied though simulations.Thirdly, a RSOA based colorless ONU with the PPM downstream signals is proposed and experimentally verified. The basic principle of RB reduction with the PPM is investigated. To compensate the degeneration of spectrum efficiency caused by PPM, a PPM based doubinary modulation method is present and demonstrated in the RSOA assisted WDM PON. The exprimental results show that employing4PPM in the downstream with～6dB extinction ratio (ER), the receiving power sensitivity is～2.4dB@BER=10-9and～3dB@BER=10-9higher than that of the NRZ modulated system in the downstream and upstream, respectively.Fourthly, to improve the modulation bandwith of the RSOA, baseband OFDM signals are introduced into the upstream of the RSOA based colorless ONU. Verifications and analysis on the he influence of the key parameters of the RSOA are provided though simulations. According to the simulation results, the modulation bandwitdth of the RSOA is extended to lOGbit/s. After40km fiber transmission, the power penalty is～2.4dB@BER=10-6.Fifthly, the photonics mm-wave generation and frequency conversion with co-polarized dual-pump FWM in SOA is studied. A typically co-polarized dual-pump SOA FWM model is present. In addition, a scheme of photonic orthogonal frequency division multiplexing (OFDM) signal frequency coversion and millimeter wave generation employing a dual driver Mach-Zehnder modulator (DDMZM) and FWM inside SOA is proposed and evaluated by theoretical analysis and simulations. The simulation results shows that this scheme is transparent to the signal formats, and the frequency of the mm-wave signal can be controlled by the frequency detuning of the dual-pump light. Moreover, the results present useful insight for the practicality of photonic mm-wave signal generation and requency conversion in the next-generation access network.