Research Of The Key Technologies For All-Optical Communication Network Based On Active Semiconductor Devices

All-optical network is considered to be the terminal communication network, since it could take full advantage of the bandwidth resource of optical fiber and is desirable to overcome the bottlenecks imposed by optic-electronic-optic conversions. All-optical signal processing is one of the most important enabling technologies for future all-optical communication network, which involves a wide range of transmission, switching, routing, accesing, and service processing. The detail technologies of all-optical signal processing include all-optical wavelength conversion, all-optical format conversion, all-optical logic gate, and photonic ultra-wideband (UWB) pulse generation, etc. The implementation of all-optical signal processing technologies usually depends on nonlinear effects in nonlinear devices. In particular, employing novel nonlinear devices, high-speed and large-capacity, supporting advanced modulation format and multiplexing method, realizing new signal processing functions, and integrating more processing functions are intensitively discussed in recent years.The electro-absorption modulator (EAM) and semiconductor optical amplifier (SOA) are two kinds of typical nonlinear devices, which have been widely used in all-optical signal processing applications due to their excellent features of low power consumption, compactness, advanced technique, and ease of integration. This dissertation is mainly focus on investigating all-optical signal processing technologies based on nonlinear effects in EAM and SOA. Several research and achievements are summarized as follows: 1. A comprehensive theoretical model for analyzing both static and dynamic properties of arbitrary composition In1-xGaxAsyP1-y and In1-x-yGaxAlyAs quantum-well (QW) EAM is proposed. Through solving Schrodinger equation, coupled-mode equation, and carrier quantity and energy density equations, variation of optical power, phase and polarization for involved waves can be calculated. The model is suitable for optimizing the device design, providing simulation platform and describing the properties of QW-EAM used in ultrafast optical signal processing applications.2. Based on the pump-probe configuration, the nonlinear effects of In1-xGaxAsyP1-y and In1-x-yGaxAlyAs QW-EAM are numerically investigated. The EAM absorption recovery is evaluated at different electric field. Then, influence of various parameters including pulse-width, optical wavelength, optical power, and QW structure on the cross-absorption modulation (XAM) nonlinear effect of EAM, as well as nonlinear phase shift and polarization rotation of the output probe signals are calculated. A wavelength-insensitive all-optical wavelength conversion scheme employing XAM effect in an EAM is numerically investigated. The variations of patterning effect and extinction ratio of the converted signals are utmost small as the original data signal wavelength ranging from1535nm to1555nm.3. An extended theoretical model with a comprehensive set of coupled-mode equations and a dynamic carrier rate equation to investigate three-input FWM effect in an SOA is presented, twelve FWM-related waves can be analized. The model possesses the capability of processing both intensity and phase modulated signals. Then, using three-input FWM arising in an SOA, we have proposed a40Gbit/s multi-function format conversion subsystem, which has the capability of processing multiple format conversions among NRZ, RZ, and CSRZ for both intensity and phase modulated signals. The compatibility among these different conversions requires no additional adjustment. Some primary10Gbit/s experimental results were demonstrated to verify the proposed subsystem, and our promising40Gbit/s simulation results have shown that the scheme is expected to perform well experimentally when40Gbit/s components are used. The input CW light serves not only as a FWM participator but also as an assist light to reduce the patterning effect of SOA. Meanwhile three identical converted signals with different wavelengths can be obtained simultaneously for all-optical wavelength multicast application.4. Based on three-input FWM arising in a single SOA, we propose an all-optical logic subsystem, an OR logic gate and two AND logic gates could be simultaneously achieved without reconfiguration. The proposed scheme could process conventional NRZ/RZ-OOK formats, as well as phase-related CSRZ-OOK format, and this compatibility can be achieved by merely turning ON or OFF an electrical driven signal. The logic operations are experimentally achieved at10Gbit/s, and the simulation research is carried out at40Gbit/s. Such a multi-function logic subsystem is utmost architecture-compact and cost-effective for future optical network nodes.5. Two novel approaches for monocycle or doublet UWB pulse generation have been proposed and demonstrated. In the first scheme, an SOA and an EAM are in parallel, by adjusting the time delay between two pump signals incident into the SOA and EAM, monocycle pulses with reversed polarities and different bandwidth can be obtained. The proposed method is flexible in pulse shaping and easy in practical optimization. In the second scheme, an SOA and SMF are in casecad to optically generate UWB pulse. By controlling the operation states of four laser diods, the proposed scheme is switchable in both pulse shape (monocycle or doublet) and pulse polarity (positive or negative), leading to the potential for pulse shape modulation (PSM) application.