Oscillators are one of the key elements in various applications as a signal source to generate periodic oscillations. Among them, an optical parametric oscillator (OPO) is a driven harmonic oscillator based on parametric frequency conversion in an optical cavity, which has been widely investigated as a coherent light source with an extremely wide wavelength tuning range. However, steady oscillation in an OPO is confined by the cavity delay, which leads to difficulty in frequency tuning, and the frequency tuning is discrete with the minimum tuning step determined by the cavity delay. Here, we propose and demonstrate a counterpart of an OPO in the optoelectronic domain, i.e., an optoelectronic parametric oscillator (OEPO) based on parametric frequency conversion in an optoelectronic cavity to generate microwave signals. Owing to the unique energy-transition process in the optoelectronic cavity, the phase evolution in the OEPO is not linear, leading to steady single-mode oscillation or multimode oscillation that is not bounded by the cavity delay. Furthermore, the multimode oscillation in the OEPO is stable and easy to realize owing to the phase control of the parametric frequency-conversion process in the optoelectronic cavity, while stable multimode oscillation is difficult to achieve in conventional oscillators such as an optoelectronic oscillator (OEO) or an OPO due to the mode-hopping and mode-competition effect. The proposed OEPO has great potential in applications such as microwave signal generation, oscillator-based computation, and radio-frequency phase-stable transfer.

振荡器是各种应用中的关键元件之一，作为产生周期性振荡的信号源。其中，光学参量振荡器（OPO）是一种基于光腔内参量变频的驱动谐振子，作为具有极宽波长调谐范围的相干光源而被广泛研究。然而，OPO的稳定振荡受到腔体延迟的限制，这导致频率调谐困难，并且频率调谐是离散的，最小调谐步长由腔体延迟决定。在这里，我们提出并演示了光电领域中OPO的对应物，即基于光电腔中的参量频率转换以产生微波信号的光电参量振荡器（OEPO）。由于光电腔中独特的能量跃迁过程，OEPO中的相位演化不是线性的，从而导致不受腔延迟限制的稳定的单模振荡或多模振荡。此外，由于光电腔内参量变频过程的相位控制，OEPO中的多模振荡稳定且易于实现，而在光电振荡器（OEO）等传统振荡器中很难实现稳定的多模振荡。或由于模式跳跃和模式竞争效应而产生的 OPO。所提出的 OEPO 在微波信号生成、基于振荡器的计算和射频相位稳定传输等应用中具有巨大潜力。