Design of Efficient Resonator-Enhanced Electro-Optic Frequency Comb Generators
Design of Efficient Resonator-Enhanced Electro-Optic Frequency Comb Generators
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DOI：
10.1109/jlt.2020.2973884
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发表时间：
2020-03-15
影响因子：
4.7
通讯作者：
Kahn, Joseph M.
中科院分区：
文献类型：
--
作者：
Buscaino, Brandon;Zhang, Mian;Kahn, Joseph M.
谐振器增强电光（RE-EO）频率梳发生器通过将光场耦合到谐振器来产生宽梳，该谐振器包含在谐振器自由光谱范围（FSR）的谐波处驱动的相位调制器。集成技术的最新进展为制造低损耗、高效率、可调谐的环基稀土电光梳状发生器提供了可能。在这项工作中，我们分析了一个典型的基于环的RE-EO梳状发生器的属性，并提出了一种新的双环梳状发生器，以提高梳状转换效率，一个特别重要的特征，基于梳状光通信系统。在简要回顾RE-EO梳状发生器在谐振操作情况下的特性之后，即，当光频和调制频率是谐振腔FSR的谐波时，我们分析了输入光相位噪声和调制相位噪声对所得梳的影响。此外，我们还分析表明，在非谐振操作中，光频偏移和调制频率偏移可以远大于谐振腔的线宽，从而增加了对制造误差的容忍度。然后，我们开发和验证数值模型来预测存在色散波导，这不能解析建模的输出光谱。使用这些精确的模型，我们分析了双环RE-EO梳状发生器，使用一个小的耦合环，以提高转换效率到32%，相比之下，一个单环RE-EO梳状发生器的1.3%的效率。然后，我们分析了点对点数据中心间的光链路，并确定双环RE-EO梳状发生器可以支持每根光纤20 Tb/s的高容量相干链路。
Resonator-enhanced electro-optic (RE-EO) frequency comb generators produce broad combs by coupling an optical field to a resonator containing a phase modulator driven at a harmonic of the resonator free spectral range (FSR). Recent advances in integration technologies have opened up the possibility of fabricating low-loss, efficient, and tunable ring-based RE-EO comb generators. In this work, we analyze the properties of a canonical ring-based RE-EO comb generator and propose a new dual-ring comb generator to increase comb conversion efficiency, an especially important characteristic for comb-based optical communications systems. After a brief review of RE-EO comb generator properties in the case of resonant operation, i.e., when the optical frequency and the modulation frequency are harmonics of the resonator FSR, we analyze the effect of input optical phase noise and modulation phase noise on the resulting comb. Additionally, we show analytically that in non-resonant operation the optical frequency offset and the modulation frequency offset can be much larger than the linewidth of the resonator, increasing the tolerance to fabrication errors. Then, we develop and validate numerical models to predict the output spectrum in the presence of dispersive waveguides, which cannot be modeled analytically. Using these accurate models, we analyze a dual-ring RE-EO comb generator that uses a small coupling ring to increase the conversion efficiency to 32%, compared to the 1.3% efficiency of a single-ring RE-EO comb generator. We then analyze a point-to-point inter-data center optical link and determine that a dual-ring RE-EO comb generator can support high-capacity coherent links at 20 Tb/s per fiber.