【作者】 张铮；

【导师】 张新亮；

【作者基本信息】 华中科技大学 ， 光学工程， 2011， 博士

【摘要】 随着对光通信传输容量需求的不断提高,新型调制格式以其较强的非线性抗性,更高的频谱效率,在近些年得到了国内外广泛的关注。新型调制格式的出现带来了一个全新的研究课题：如何进行新型调制格式的全光信号处理。论文在国家863计划、国家重点基础研究发展计划、国家自然科学基金和华为专项基金项目的支持下,系统研究了基于非线性器件和滤波器件实现新型调制格式的全光信号处理,包括全光2R再生、全光再定时和全光码型转换等,主要研究成果和学术贡献有如下几个方面：(1)本论文首先通过时域特性与频域特性的对比分析,介绍了传统调制格式和新型调制格式的区别。然后介绍了高速波分复用系统(WDM)中普遍存在的传输损伤,引出了本文需要研究的内容。(2)提出了一种基于量子阱半导体光放大器(QW-SOA)的相位调制格式强度再生方案。选择合适的工作条件,基于QW-SOA较小的线宽增强因子,差分相移键控(DPSK)的强度噪声能被极大的抑制,同时不会引入过多的相位噪声。简要研究了线宽增强因子较大的体材料SOA的再生性能,并分析了多信道的强度再生特性。(3)提出了基于非线性光纤环镜(NOLM)的相位调制信号相位和强度同时再生的方案。在插入SOA后,首次实现了强度噪声过大以及相位噪声和强度噪声同时过大两种情况下的DPSK信号再生。同时展示了此方案对正交差分相移键控信号(DQPSK)和多信道DPSK信号再生的可行性。模拟结果表明,使用再生装置后,信号的质量得到了极大的改善,传输距离得到了扩展。(4)提出了基于半比特延时干涉仪(DI)和窄带滤波器的归零差分相移键控(RZ-DPSK)到非归零差分相移监控(NRZ-DPSK)的码型转换。同时通过采用半比特DI和一个100GHz的DI,或者用阵列波导光栅(AWG)代替100GHz DI,分别实现了6信道的20Gbit/s RZ-DPSK到NRZ-DPSK以及6信道40Gbit/s的载波抑制差分相移键控(CSRZ-DPSK)到NRZ-DPSK的码型转换。(5)提出了一种基于相位调制器(PM)和失谐滤波器的全光NRZ-D(Q)PSK到RZ-D(Q)PSK信号的码型转换方案,通过模拟分析了信号的波形图,频谱图和眼图,证明了转换的有效性。同时当输入的信号为带有时间抖动的RZ-D(Q)PSK信号时,还能对失真的信号做再定时处理。此方案可适用于多信道同时处理,在使用较为成熟的电信号时钟恢复的同时,避免了光电光的转换。更多还原

【Abstract】 With increasing demand of transmission capacity, advanced modulated formats, which offer better nonlinearity tolerance and high spectral efficiency, have been receiving increasing attention in recent years. The use of these phase modulated formats brings new research fields:how to do all optical processing on advanced modulated formats.Sponsored by National Natural Science Foundation of China, National High Technology Research and Development Program of China, the National Basic Research Program of China and Project of Huawei Technology, all optical processing of phase modulated formats, such as all optical 2R, all optical retiming, all optical format conversion between diferential phase shift keying (DPSK) are fully-and systemically investigated, using optical nonlinear device and passive optical filter. The main research achievements and contributions are summarized as followings:(1) The generation and characteristics of various modulation formats used in optical communications are investigated and compared, in time and frequency domain. The impairments of wavelength division multiplexing (WDM) networks are analyzed and discussed, which shows the main problem of the phase modulated formats.(2) A simple amplitude regeneration scheme for phase modulated signals, such as return-to-zero differential-phase-shift keying (RZ-DPSK) signal, based on quantum-well (QW)-semiconductor optical amplifier (SOA) is investigated systematically. By choosing the proper parameters, due to the low linewidth enhancement factor (a-factor), the amplitude fluctuations are suppressed while the phase information is preserved. The regeneration property of the bulk SOA with large linwidth enhancement factor and the potiential use in WDM system are also investigated.(3) All optical phase and amplitude regeneration scheme for phase modulated signal based on nonlinear fiber loop mirror configuration is investigated systematically. By using additional SOAs, for the first time, the regeneration processes for the situation with large amplitude noise and situation with large amplitude noise plus large phase noise have been investigated and the regeneration have achieved. And it is versatile to multichannel DPSK and Differential Quadrature Reference Phase Shift Keying (DQPSK) signals. The performance of regenerated signal is greatly improved. A significant improvement of eye opening and transmission length expansion can be observed for DPSK signal, multichannel DPSK signals and DQPSK signal, respectively.(4) The conversions from return-to-zero differential phase shift keying (RZ-DPSK) to non-return-to-zero DPSK (NRZ-DPSK) are investigated. By using a 0.5 bit time delay DI and lnm bandpass filter. Single channel format conversion scheme at 40Gbit/s is demonstrated. By using a 0.5 bit time delay DI and a 100GHz DI, or an array waveguide grating (AWG), multi-channel format conversion at both 20Gbit/s and 40Gbit/s are demonstrated.(5) A new kind of all optical format conversion from NRZ-D(Q)PSK to RZ-D(Q)PSK signal is proposed by using phase modulators and detuning filters. The optical spectra, temporal waveforms and eye diagrams are studied in detail to confirm the successful realization of NRZ-D(Q)PSK to RZ-D(Q)PSK format conversion. Furthermore, the same scheme may also be robust in RZ-D(Q)PSK retiming with WDM practice. The use of mature electrical clock recovery module while.avoiding optical-electrical-optical (O-E-O) operation may be potential in practical use.更多还原