光学频率梳在光子模拟信号处理中的应用研究

发布时间：2018-08-13 19:38

【摘要】：光学频率梳是指一系列具有固定谱线间隔的相干谱线,且谱线之间具有稳定的相位关系。从频域上来看,光学频率梳是一个相干性能良好的大带宽的梳状谱,由多个频率分量组成,因此可以用来作为密集波分复用(DWDM)系统的光源；而从时域上来看,光学频率梳则对应为一个超短脉冲序列,可以很好地用来作为光时分复用(OTDM)系统的光源。随着激光技术的日益成熟以及光通信技术的不断发展,光学频率梳由于其广泛的应用前景吸引了越来越多人的关注,光学频率梳也成为继超短脉冲激光问世之后激光技术领域的又一重大突破。由于光频率在频域上展现出较大的带宽,因此可以通过对频谱的幅度和相位进行调控从而实现光子模拟信号处理。光子模拟信号处理充分利用了光子的巨大带宽资源、避免了电子瓶颈带来的限制、提高了系统的实时性,因此在全光通信网络中占有举足轻重的地位。此外,硅基波导由于具有结构紧凑、可集成且能与传统的互补金属氧化物半导体(CMOS)工艺兼容等优点,近年来也越来越受到人们的关注。光子集成电路用于光子模拟信号处理也打开了实现超高速和超宽带信号处理的可能性。未来的光电子器件也将朝着微型化和集成化发展。本论文重点研究高性能光学频率梳的产生方法,以及结合硅基光子器件探索光学频率梳在光子模拟信号处理中的应用。主要的研究内容如下：(1)详细介绍了光学频率梳的特点和性质,以及其研究背景与意义,并概述了光学频率梳的研究现状。总结了几种常用的产生光学频率梳的方案,并简要对比分析了这些方案各自的优缺点。此外,简要介绍了开展光子模拟信号处理研究的意义,以及常用的实现光子模拟信号处理的方法,并总结了目前国内外在光子模拟信号处理方面取得的进展。(2)对高非线性光纤(HNLF)在光学频率梳产生中的应用进行了实验研究。提出了利用HNLF中的级联四波混频效应产生光学频率梳的方案、利用HNLF中的自相位调制效应产生光学频率梳的方案以及同时利用HNLF中的级联四波混频和自相位调制效应产生光学频率梳的方案。通过实验对比分析了HNLF中级联四波混频和自相位调制效应对于产生的光学频率梳的性能影响。实验结果显示,HNLF中的级联四波混频和自相位调制效应均能产生大带宽的光学频率梳,且均具备中心波长以及频率间隔可调谐。在相同泵浦功率和重复频率的前提下,基于HNLF中的级联四波混频效应能产生更多的频率谱线；而基于HNLF中的自相位调制效应能得到更平坦的光学频率梳。此外,对应到时域上,基于这两种非线性效应均能得到超短脉冲输出,且脉宽可调谐。(3)提出了一种使用级联时域透镜产生光学频率梳的方案。首先基于空间-时间二元性和时域-频域二元性,详细介绍了时域透镜的概念、时域成像的条件以及频域泰伯(Talbot)效应成立的条件。利用两个时域透镜级联,分别实现了频域-时域映射和频域Talbot效应。频域-时域映射得到了多频率分量输出；在此基础上,再利用频域Talbot效应,对频率间隔进行进一步分割,产生新的频率分量,实现谱线数量成倍增加。实验结果表明,基于级联时域透镜能产生光学频率梳,且谱线数量和频率间隔均能实现灵活调谐。(4)使用硅基光子器件作为频谱调控器件,开展了光学频率梳在光子模拟信号处理中的应用研究,实现了一阶光学微分器、一阶光学希尔伯特变换、可调谐分数阶微分器以及简单的光学任意波形产生。其中,基于单个微盘谐振器,既能实现一阶光学微分也能实现一阶光学希尔伯特变换,且首次从实验上验证了两者之间的联系与区别。实验结果显示,当输入信号具有较大脉宽时,单个微盘谐振器可以用来作为光学微分器；当输入信号具有较小脉宽时,单个微盘谐振器能用来作为光学希尔伯特变换器。(5)首次提出了一种基于光学频率梳和电调微环谐振器来实现时域隐身的方案。提出将光学频率梳与电调微环谐振器结合,代替时域透镜的功能,模拟分析了其实现时域隐身的可行性。并进一步从实验上,实现了对时钟信号和数据信号的时域隐身。
[Abstract]:Optical frequency comb is a series of coherent spectral lines with fixed spectral line spacing and stable phase relationship between them.In frequency domain, optical frequency comb is a large bandwidth comb spectrum with good coherence performance and consists of many frequency components, so it can be used as a light source for dense wavelength division multiplexing (DWDM) system. In time domain, optical frequency comb is an ultra-short pulse sequence, which can be used as the light source of optical time division multiplexing (OTDM) system. With the development of laser technology and optical communication technology, optical frequency comb attracts more and more people's attention because of its wide application prospects. Photon analog signal processing can be realized by adjusting the amplitude and phase of the spectrum. Photon analog signal processing makes full use of the enormous bandwidth resources of photons and avoids it. In addition, silicon-based waveguides have attracted more and more attention in recent years because of their compact structure, integration and compatibility with traditional complementary metal oxide semiconductor (CMOS) processes. Circuit-based photonic analog signal processing also opens up the possibility of ultra-high speed and ultra-wideband signal processing. Future optoelectronic devices will also develop towards miniaturization and integration. The main research contents are as follows: (1) The characteristics and properties of optical frequency comb, its research background and significance are introduced in detail, and the research status of optical frequency comb is summarized. Several common schemes for generating optical frequency comb are summarized, and their advantages and disadvantages are analyzed briefly. In this paper, the significance of photon analog signal processing and the common methods of photon analog signal processing are introduced, and the progress of photon analog signal processing at home and abroad is summarized. (2) The application of high nonlinear optical fiber (HNLF) in optical frequency comb generation is studied experimentally. A cascaded four-wave mixing (CWM) scheme based on cascaded four-wave mixing (CWM) and a self-phase modulation (SPM) scheme using the self-phase modulation (SPM) effect in HNLF to generate optical frequency combs are proposed. The experimental results show that both cascaded four-wave mixing and self-phase modulation in HNLF can produce a wide bandwidth optical frequency comb with tunable center wavelength and frequency interval. More frequency lines should be generated, and the optical frequency comb can be flattened based on the self-phase modulation effect in HNLF. In addition, the ultra-short pulse output can be obtained based on the two nonlinear effects in time domain, and the pulse width can be tuned. (3) A scheme for generating optical frequency comb using cascaded time-domain lenses is proposed. Based on space-time duality and time-frequency duality, the concept of time-domain lens, imaging conditions in time-domain and Talbot effect in frequency-domain are introduced in detail. The experimental results show that the cascaded time-domain lens can generate optical frequency combs, and the number of spectral lines and frequency intervals can be flexibly tuned. (4) Using silicon-based photonic devices as spectra. The application of optical frequency comb in photonic analog signal processing is studied. First-order optical differentiator, first-order optical Hilbert transform, tunable fractional-order differentiator and simple optical arbitrary waveform generation are realized. Based on a single micro-disk resonator, both first-order optical differential and first-order optical waveform can be realized. The experimental results show that a single disk resonator can be used as an optical differentiator when the input signal has a large pulse width, and a single disk resonator can be used as an optical Hilbert converter when the input signal has a small pulse width. (2) A scheme of time domain stealth based on optical frequency comb and electrically tuned microring resonator is proposed for the first time. The optical frequency comb is combined with electrically tuned microring resonator to replace the function of time domain lens. The feasibility of time domain stealth is simulated and analyzed. Stealth in time domain.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN911.7

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