Studies On Several Key Technologies In Optical Packet Switched Networks

Owing to Dense Wavelength Division Multiplexing (DWDM), over Tb/s transmission can be achieved in a single optical fiber. The optical transmission network currently faces the challenge, which is how to integrate the immense bandwidth of optical transmission technology with the new data services borne efficiently and agilely by the Internet Protocol (IP) switching technology. The optical packet switching (OPS) is thus proposed to solve the problems.In the optical packet switching networks (OPSN), data services are carried in the optical packets. The transmission and switching of the payload are accomplished in the optical domain, and the processing and control of the header are accomplished in the optical or electric domain. The OPS supports the multi-granularities services and improves the bandwidth utilization, because the smallest switching granularity is optical packet and the bandwidth is allocated agilely according to the consumers' demands in the OPSN. The theme of my thesis includes some key technologies in OPSN. The works are listed in the following:A new method of crosstalk coefficient to modeling the crosstalk in SOA switch gate based on XGM is applied in chapter 2. We also use a traffic model to describe the difference of balanced and unbalanced traffic in OPS node. Cross-talk-induced bit error rate (BER), switching node dimension and switch cascaded capability under unbalanced traffic are examined, which proves to be relevant to the SOA parameters, the signal properties and the traffic model unbalanced degree. Several rules are drawn to facilitate the design of SOA-based switching matrix under unbalanced traffic.In chapter 3, the all-optical exclusive OR gate using integrated SOA-based Mach-Zehnder interferometer sped-up by an assistant light is proposed for the first time. Through numerical simulations, it is shown that by using a continuous wave (CW) assistant light to increase the gain recovery rate of SOA, the operation speed limit of the XOR gate can be increased. The SOA parameters and the assistant light energy are discussed and designed to optimize the performance of the XOR gate.We discussed the all optical buffer technology used in optical packet switching networks in chapter 4. The performance of optical buffer in prioritized optical packet switching is investigated. The model of Pareto distribution and prioritized queuing are established. We also investigate the performances of optical packet switches in which the wavelength converters are shared per input channel (SPIC) and optical buffers are partially shared working in unicast and multicast ways through analyzing a traffic model.Chapter 5 gives a novel all-optical header and payload separation technique that can be utilized in un-slotted optical packet switched networks. The technique uses a modified TOAD for packet header extraction with differential modulation scheme and...