Silicon-on-Insulator based Integrated Optical Frequency Combs for Microwave, THz and Optics

频率梳的精度、通用性和宽带宽是许多不同应用的基础，从微波到毫米和太赫兹，再到电磁频谱的光学范围。原则上，每个锁模激光器（MLL）产生一个频率梳状频谱。因此，经典的梳状产生技术依赖于高功率mls在光纤中产生超连续介质。通过自我参照，这些宽梳，跨越一个八度，可以非常精确地稳定。频率梳的一个非常有趣的来源是锁模，掺铒飞秒光纤激光器，因为它们成本低，坚固且易于获得。然而，即使是非常紧凑的光纤激光器的尺寸通常为12 x 20 x 7 cm³（来自Toptica的FemtoFerb 1560），对于集成全光学采样或轻型分光镜等应用来说也太大了。最近研究表明，利用级联四波混频（FWM）的参数效应，非常紧凑的高Q腔可以产生非常宽带的频率梳。在这些成功之后，DARPA宣布了一个新的研究领域，用于开发芯片级光学频率梳。然而，许多这些项目的目标是产生尽可能广泛的频率梳。由于相对较高的自由光谱范围和有限的可调性，这些梳不能用于许多不同的应用。与此相反，这里我们想研究用于微波、太赫兹和光学频率范围的集成频率梳源。所有这些应用都不需要自参考梳。因此，八度程跨越梳将不会被研究。相反，这个项目的目的是获得可调谐和稳定的、CMOS兼容的、集成的梳状源，用于计量、所有光学采样和光纤无线电等领域的应用，以及研究整个系统是否以及如何在未来可能的步骤中集成。如果成功，该项目将为微波、太赫兹和光谱学的轻型设备，为采样率为几百Gsps的所有光学采样的集成设备以及为光纤无线电应用的太赫兹和微波产生的集成源铺平道路。

The precision, versatility and broad bandwidth of frequency combs are the basis of many different applications from the microwave via the millimeter and THz up to the optical range of the electromagnetic spectrum. In principle, every mode locked laser (MLL) produces a frequency comb spectrum. Thus, classical comb generation techniques rely on high power MLLs generating a supercontinuum in optical fibers. By self referencing, these broad combs, spanning an octave, can be stabilized very precisely. A very interesting source of frequency combs are mode locked, erbium doped femtosecond fiber lasers since they are low cost, robust and readily available. However, even a very compact fiber laser has dimensions of typically 12 x 20 x 7 cm³ (FemtoFerb 1560 from Toptica), much too big for applications like integrated all optical sampling or lightweight spectroscopes for instance. Recently it has been shown that very compact high Q cavities can generate very broadband frequency combs by the parametric effect of cascaded four wave mixing (FWM). Following these successes the DARPA announced a new research field for the development of chip scale optical frequency combs. The aim of many of these projects, however, is the generation of frequency combs which are as broad as possible. Due to the relatively high free spectral range and the limited tunability of these combs, they cannot be used for many different applications. In contrast to this, here we want to investigate integrated frequency comb sources for applications in the frequency ranges of microwave, THz and Optics. All of these applications do not need a self referenced comb. Thus, octave spanning combs will not be investigated. The aim of this project, instead, is to get tunable and stabilized, CMOS compatible, integrated comb sources for applications in fields like metrology, all optical sampling and radio over fiber and the investigation if and how the whole systems could be integrated in a possible future step. If successful, the project could pave the way to lightweight devices for microwave, THz and optical spectroscopy, for integrated devices for all optical sampling with sampling rates of several hundred Gsps and integrated sources for THz and microwave generation for radio over fiber applications.