Nonlinearity-Based Manipulation And High Capacity Transmission Technologies Of Optical Signal

With the rapid development of information technology, fiber transmission has become the key technology for the backbone communication network and access network due to the low loss, low weight, small volume, broad bandwidth and immunity to electromagnetic interference. In resent years,400-Gibt/s and even 1-Tbit/s optical communication technologies have attracted increase interests to meet ever-growing capacity and bandwidth requirements. On the other hand, with increase of the transmission rate and capacity, optical signals would suffer from many distortions, such as chromatic dispersion, nonlinearity, etc. Therefore, signal manipulation and high capacity transmission technologies play the more important role in the next generation optical network. Among them, signal manipulation consists of generation, processing, filter and distortion compensation, etc., while high capacity transmission technology comprises wavelength division multiplexing, optical time division multiplexing, polarization division multiplexing and so on. This work focuses our researches on the nonlinear manipulation and transmission technologies of optical signal. The aims are to develop some novel all-optical signal processing based on fiber nonlinearity, novel distortion compensation of microwave photonic signal and novel multi-polarization division multiplexing transmission (MPDM), and hence, to provide some potential and alternative approaches for next generation optical networks in terms of enhancing system reconfigurablility, increasing transmission capacity and performance.This dissertation, extensively studied nonlinear manipulation and high capacity transmission techniques of optical signal theoretically and experimentally. The main contents include the following parts. Firstly, by analyzing the mechanism of fiber linearity and nonlinearity, a frequency response express of microwave photonic system is obtained. Then, three solutions for all-optical signal processing are proposed and experimentally demonstrated based on fiber nonlinear effects, such as phase sensitive amplifier (PSA), wavelength multicasting and optical signal-to-noise ratio (OSNR) monitoring. Afterwards, we concentrate our researches on signal manipulations for microwave photonic signal, including dispersion and nonlinearity compensation techniques. Finally, a novel MPDM transmission strategy is explored, and its effectiveness in short-reach transmission, microwave photonic area and long-haul transmission are demonstrated. The detail achievements of this dissertation are listed as following:(1) A simple frequency response expression of the microwave photonic system is obtained based on nonlinear coupled-mode theory and small-signal analysis. Such expression consists of a serial of terms that correspond to chromatic dispersion (CD), polarization-mode-dispersion (PMD) and fiber nonlinearity. Based on proposed model, less computation requirements are achieved. Meanwhile, the noise figure (NF) and spurious-free dynamic range (SFDR) limitations are investigated for the dispersive nonlinear transmission link, which indicates that the performance of signal is dependent on the transmitted frequency.(2) Three functional devices are proposed based on fiber nonlinear effects, including phase sensitive amplifier (PSA), wavelength multicasting and OSNR monitoring, which could solve bandwidth limitation and realize the real-time digital signal processing in optical communication network.1) PSA is investigated by simulation based on non-degenerated four-wave mixing (FWM). After PSA, the degraded BPSK signal and QPSK signal are regenerated; 2) wavelength multicasting are experimentally demonstrated based on cascaded FWM, where one to nine multicasting of RZ-DPSK signal is achieved with error-free performance; 3) OSNR monitoring is experimentally demonstrated based on FWM. By measuring the power of higher-order FWM component, the OSNR performances for two tributaries can be monitored simultaneously in polarization division multiplexing (PDM) systems, and the monitoring range is larger than 10-dB.(3) A serial of CD and nonlinearity compensation schemes for the microwave photonic signals are proposed and demonstrated experimentally, which improve the spuring free dynamic range (SFDR) of microwave photonic system.1) Prediction-based single frequency CD compensation is realized by properly tuning the bias of the dual-electrode Mach-Zehnder modulator (DE-MZM) and the relative phase difference between two input RF signals; 2) polarization effct-based single frequency CD compensation improves the SFDR of 12-dB by adjusting the polarization before phase modulator. Such scheme avoids the bias drifting of conventional intensity modulator; 3) polarization-diversity-based broadband CD compensation could achieve the simultaneous compensation for multi-channel and multi-frequency signals by combining two complementary links. After compensation, SFDR improvement of 12-dB is obtained, and the error vector magnitude (EVM) reduces to 5%; 4) digital signal processing-based on adaptive nonlinearity compensation has been experimentally demonstrated by simulating the back-propagation for the microwave photonic signal. Only two parameters (i.e. the central frequency and bandwidth of the converted RF signal) are necessary, and the SFDR of the link can reach ～126-dB·Hz4/5 after compensation; 5) a method to improve SFDR of microwave photonic links is experimentally demonstrated based on polarization effect as well. By adjusting the states of polarization (SOPs) launching into the PM and the polarizer, the nonlinearity and CD can be compensated simultaneously. The SFDR achieves ～110-dB·Hz4/5 for a 40-km fiber transmission after compensation.(4) Three novel MPDM technologies are proposed based on coherent detection and DSP, which provide the new ideas to further increase the spectral efficience (SE) of optical communication system.1) The characteristic of four-polarization multiplexed on-off-keying (4PM-OOK) signal transmission are explored, and then the impact of the crosstalk from polarization mode dispersion (PMD) on 4PM systems are discussed.80-km transmission at the rate of 40Gbit/s is achieved in simulation. Such scheme provides the novel networking technology for the optical access network with short-reach transmission; 2) the multiplexing and demultiplexing scheme of 4PM-radio-over-fiber (4PM-RoF) signal is successfully realized.60-km single-mode fiber transmission is achieved in simulation. Such scheme improves SE of the microwave photonic system; 3) the tranmission strategy of 4PM-differential phase-shift-keying (4PM-DPSK) signal is demonstrated experimentally. 150-km SMF transmission at 100-Gbit/s is achieved successfully. Such scheme increases the transmission capacity of optical backbone communication network with long-haul transmission.Considering the rapid development of optical communication system and future 5G technique, manipulation and high capacity transmission of optical signal will face more and more challenges for the novel signal modulation formats, signal transmission strategies and new business requirements. One of the ongoing researches will focus on signal manipulation and transmission techniques.