Univ. Grenoble Alpes, CNRS, LIPHY, 38000, Grenoble, France.
Institut National de la Recherche Scientifique - Energie, Matériaux et Télécommunications (INRS-EMT), Varennes, QC, J3X1S2, Canada.
Nat Commun. 2018 Jun 22;9(1):2438. doi: 10.1038/s41467-018-04822-4.
Broadband radio-frequency chirped waveforms (RFCWs) with dynamically tunable parameters are of fundamental interest to many practical applications. Recently, photonic-assisted solutions have been demonstrated to overcome the bandwidth and flexibility constraints of electronic RFCW generation techniques. However, state-of-the-art photonic techniques involve broadband mode-locked lasers, complex dual laser systems, or fast electronics, increasing significantly the complexity and cost of the resulting platforms. Here we demonstrate a novel concept for photonic generation of broadband RFCWs using a simple architecture, involving a single CW laser, a recirculating frequency-shifting loop, and standard low-frequency electronics. All the chirp waveform parameters, namely sign and value of the chirp rate, central frequency and bandwidth, duration and repetition rate, are easily reconfigurable. We report the generation of mutually coherent RF chirps, with bandwidth above 28 GHz, and time-bandwidth product exceeding 1000, limited by the available detection bandwidth. The capabilities of this simple platform fulfill the stringent requirements for real-world applications.
宽带射频啁啾波形（RFCWs）具有动态可调参数，这对许多实际应用具有重要意义。最近，已经证明光子辅助解决方案可以克服电子 RFCW 产生技术的带宽和灵活性限制。然而，最先进的光子技术涉及宽带锁模激光器、复杂的双激光系统或高速电子学，这大大增加了所得到的平台的复杂性和成本。在这里，我们展示了一种使用简单架构的宽带 RFCW 光子产生的新概念，该架构涉及单个 CW 激光、循环频率移位环和标准低频电子学。所有啁啾波形参数，即啁啾率的符号和值、中心频率和带宽、持续时间和重复率，都可以轻松重新配置。我们报告了具有超过 28GHz 的带宽和超过 1000 的时带宽乘积的互相干 RF 啁啾的产生，受可用检测带宽的限制。该简单平台的功能满足了实际应用的严格要求。
