The integrated microwave photonic filter (MPF), as a compelling candidate for next-generation radio-frequency (RF) applications, has been widely investigated for decades. However, most integrated MPFs reported thus far have merely incorporated passive photonic components onto a chip-scale platform, while all necessary active devices are still bulk and discrete. Though few attempts to higher photonic integration of MPFs have been executed, the achieved filtering performances are fairly limited, which impedes the pathway to practical deployments. Here, we demonstrate, for the first time to our knowledge, an all-integrated MPF combined with high filtering performances, through hybrid integration of an InP chip-based laser and a monolithic silicon photonic circuit consisting of a dual-drive Mach–Zehnder modulator, a high-$Q$ ring resonator, and a photodetector. This integrated MPF exhibits a high spectral resolution as narrow as 360 MHz, a wide-frequency tunable range covering the S-band to K-band (3 to 25 GHz), and a large rejection ratio of $>40\mathrm{dB}$. Moreover, the filtering response can be agilely switched between the bandpass and band-stop function with a transient respond time ($\sim 48\mathrm{\mu s}$). Compared with previous MPFs in a similar integration level, the obtained spectral resolution in this work is dramatically improved by nearly one order of magnitude, while the valid frequency tunable range is broadened more than twice, which can satisfy the essential filtering requirements in actual RF systems. As a paradigm demonstration oriented to real-world scenarios, high-resolution RF filtering of realistic microwave signals aiming for interference rejection and channel selection is performed. Our work points out a feasible route to a miniaturized, high-performance, and cost-effective MPF leveraging hybrid integration approach, thus enabling a range of RF applications from wireless communication to radar toward the higher-frequency region, more compact size, and lower power consumption.

中文翻译：

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具有可切换响应的混合集成高性能微波光子滤波器

几十年来，集成微波光子滤波器 (MPF) 作为下一代射频 (RF) 应用的引人注目的候选产品，已被广泛研究。然而，迄今为止报道的大多数集成 MPF 仅将无源光子组件集成到芯片级平台上，而所有必要的有源器件仍然是散装和分立的。尽管已经执行了对 MPF 进行更高光子集成的尝试，但实现的过滤性能相当有限，这阻碍了实际部署的途径。在这里，我们首次展示了全集成 MPF 与高滤波性能相结合，通过混合集成基于 InP 芯片的激光器和由双驱动 Mach-Zehnder 调制器组成的单片硅光子电路， 高-$问$环形谐振器和光电探测器。这种集成的 MPF 具有窄至 360 MHz 的高光谱分辨率、覆盖 S 波段至 K 波段（3 至 25 GHz）的宽频率可调范围以及高达$>40\mathrm{D\; b}$. 此外，滤波响应可以在带通和带阻功能之间灵活切换，具有瞬态响应时间（$～48\mathrm{微秒}$）。与之前类似集成水平的 MPF 相比，本文获得的光谱分辨率显着提高了近一个数量级，同时有效频率可调范围扩大了两倍以上，可以满足实际射频系统中必不可少的滤波要求. 作为面向现实世界场景的范例演示，执行了针对干扰抑制和信道选择的现实微波信号的高分辨率 RF 滤波。我们的工作指出了一条利用混合集成方法实现小型化、高性能和具有成本效益的 MPF 的可行途径，从而使从无线通信到雷达的一系列射频应用向更高频率区域、更紧凑的尺寸和更低的能量消耗。