All-optical Signal Processing Technologies Based On The Nonlinearities Of SOA And EAM In Optical Network

The increasing of requirement for transmission speed and capacity from market has greatly accelerated the development of fiber transmission technologies in high speed, large capacity and ultra long haul Dense Wavelength Division Multiplexing (DWDM) system. All-optical switched network is believed to be the future developing direction, in which the realization of all-optical switching will not only overcome the electrical bottleneck, but offer the network dominances of scalability, ultra-high speed, transparency, switching granularity diversity and high resources efficiency etc. In all-optical switched network, all-optical signal processing is essential, and in all-optical signal processing, optical modulation formats conversion, all-optical wavelength conversion and all-optical clock recovery are key components.This dissertation mainly focuses on the subject of photonic technologies based on semiconductor optical amplifiers (SOAs) and electroabsorption modulator (EAM) nonlinearities in optical network, including all-optical modulation format conversion, all-optical wavelength conversion and all-optical clock recovery. The works in this dissertation include simultaneously all-optical inverted and noninverted wavelength conversion employing SOA-based Sagnac interferometer, All-optical clock recovery from CSRZ-format data using SOA-Based ring laser, All-optical NRZ-RZ format conversion with wavelength Conversion using an Electro-Absorption Modulator, all-optical wavelength conversion based on XBM in EAM and optical packet header extraction using SOA-DI structure for the corresponding theoretical analysis and experimental research. The main works and conclusions are listed as follows:1. First, a brief introduction of the all-optical packet switching network development situation and prospects, also all-optical packet switching network and the key technologies required for all-optical information processing and application development for a brief introduction.2. In Chapter 2, we have simulated and experimentally demonstrated simultaneously all-optical inverted and noninverted wavelength conversion using an SOA-based Sagnac interferometer for the first time to our knowledge. First, we have built the model of simultaneously RZ modulation format data inverted and noninverted wavelength conversion using the all-optical switching effect.Simulation theories have explained the mechanism of this technology and the realization of TOAD window of time to the ER effect of wavelength converted signal.And we have demonstrated simultaneously RZ modulation format data all-optical inverted and noninverted wavelength conversion at 10Gbit/s rate using an SOA-based Sagnac interferometer for the first time.Meanwhile, we have analysised experimental study of the SOA bias current to the ER effect of wavelength converted signal.3. In Chapter 3, a model based on SOA-based ring laser is proposed for numerically analyzing the clock performance. We have analysised a novel modulation format CSRZ data to all-optical clock recovery. The results show that the pulsewidth and power of the injected CSRZ data and bias currents of SOA have great influence on the performance of the recovered clock pulses, such as amplitude fluctuation and timing jitter to optimize system performance in a meaningful guidance.4. In chapter 4 of part one, a novel scheme is presented to realize simultaneous all-optical non-return-to-zero (NRZ) to return-to-zero (RZ) format conversion and wavelength conversion in an electro-absorption modulator (EAM) based on cross-absorption modulation (XAM) at 10Gbit/s is demonstrated for the first time. The impact of the bias voltage of EAM and the input NRZ data signal power on the performance of converted RZ signal is studied. By tuning the wavelength of input NRZ signal from 1550nm to 1570nm. Error-free BER all-optical operation of format conversion with wavelength conversion for the first time using EAM is reported at 10Gbit/s.In Chapter 4 of part two, all-optical wavelength conversion at 10Gbit/s is demonstrated by direct cross-bias modulation (XBM) in a simple EAM. Experimental study on the feasibility of scheme through the experimental research, through XBM make EAM at unsaturated state, realize 10Gbit/s NRZ data all-optical wavelength conversion. The wavelength converter is experimentally demonstrated at 10Gbit/s rate over up-conversion range 10.2 nm.5. In chapter 5, a novel scheme of optical packet header extraction for OTDM networks is presented based on SOA-DI structure. The novel scheme is based on the effect of SOA gain saturation using DI structure interfere to achieve optical packet header extraction. The paper explains principle of the scheme, and analyzes the influence of some parameters on optical packet header extraction, such as the energy of input pulses,the pulse-width of input pulses,small signal gain of SOA and SOA-DI interfere time-delayed. The scheme is simple and easy to achieve.