Photonic-assisted ingenious agile non-periodic oscillator (PIANO)

The development of high-performance frequency-agile microwave signal generators has long been constrained by the inherent limitations of electronic technology. To overcome this challenge, researchers have increasingly turned to photonics, leveraging its high-frequency and broad-bandwidth capabilities. Here, we introduce and demonstrate a Photonic-assisted Ingenious Agile Non-periodic Oscillator (PIANO), which enables high-performance frequency-agile microwave signal generation with flexible frequency agility, ultra-low phase noise, rapid switching speed, and large time-bandwidth product (TBWP). The key innovation of PIANO lies in incorporating a dynamic frequency-shifting module into an optoelectronic oscillator (OEO) cavity, thereby extending the conventional delay-based OEO framework by decoupling frequency-agility behavior from the cavity-delay constraint. During experiments, PIANO successfully generated various flexible frequency-agile waveforms, with a frequency-switching time of 27 ns, phase noise as low as −134 dBc/Hz@10 kHz, and TBWP up to 1,440,000. This work offers a promising approach to high-performance frequency-agile microwave signal generation for applications such as radar and communication systems. The study presents PIANO, a microwave photonic oscillator that generates frequency-agile microwave signals with rapid switching and ultra-low phase noise, while overcoming the cavity-delay constraint of conventional delay-based oscillators.