We report the demonstration of an instantaneous frequency measurement system based on the four-wave mixing (FWM) effect in short dispersion engineered slow-light silicon photonic crystal waveguides for RF frequency measurement purposes within a range of 10 MHz to 80 GHz. Three nonlinear media were investigated including 3 mm ridge waveguide, 80 µm nanowire, and 80 µm photonic crystal (PhC). The system size could thus be decreased, and as a result system integration would become possible. We have shown that the optical power required to excite FWM is low enough to remove any need for optical amplification, and hence the system noise floor will be kept low. Issues due to the amplifier saturation will also be resolved this way. As a result, no noise reduction system, like lock-in amplification, would be required. A better system latency will also be achieved accordingly. The system dynamic range would also be improved in two ways. First, due to the low noise floor, and second, because of removing any optical amplifier that possibly could become saturated at higher power levels. All three media behaviors were simulated by the split step Fourier method, and the results showed that the best medium to be used is PhC.

中文翻译：

---

利用硅光子晶体内四波混频的慢光增强进行微波频率测量

我们报告了基于四波混合 (FWM) 效应的瞬时频率测量系统的演示，该系统基于短色散工程慢光硅光子晶体波导，用于 10 MHz 至 80 GHz 范围内的 RF 频率测量。研究了三种非线性介质，包括 3 mm 脊形波导、80 µm 纳米线和 80 µm 光子晶体 (PhC)。因此可以减小系统尺寸，从而使系统集成成为可能。我们已经表明，激发 FWM 所需的光功率足够低，可以消除对光放大的任何需要，因此系统本底噪声将保持在较低水平。放大器饱和引起的问题也将通过这种方式解决。因此，不需要像锁定放大这样的降噪系统。也将相应地实现更好的系统延迟。系统动态范围也将通过两种方式得到改善。首先，由于低本底噪声，其次，因为去除了任何可能在较高功率水平下饱和的光放大器。所有三种介质行为都通过分步傅立叶方法进行模拟，结果表明使用的最佳介质是 PhC。