Due to their single-crystalline structures, comparatively large aspect ratios, tight optical confinement and smooth surfaces, nanowires have increasingly attracted research interests for both fundamental studies and technological applications in on-chip photonic devices. This class of nanostructures typically have cross-sections of 2~200 nm and lengths upwards of several micrometers, allowing for the bridging of the nanoscopic and macroscopic world. In particular, the lasing behaviors can be established from a nanowire resonator with positive feedback via end-facet reflection, making the nanowire a promising candidate in the next generation of optoelectronics. Consequently, versatile nanowire-based devices ranging from nanoscale coherent lasers, optical sensors, waveguides, optical switching, and photonic networks have been proposed and experimentally demonstrated in the past decade. In this article, significant progresses in the nanowire fabrication, lasers, circuits, and devices are reviewed. First, we focus on the achievements of nanowire synthesis and introduce the basics of nanowire optics. Following the cavity configurations and mode categories, then the different light sources consisting of nanowires are presented. Next, we review the recent progress and current status of functional nanowire devices. Finally, we offer our perspective of nanowires regarding their challenges and future opportunities in photonic circuits.

由于其单晶结构、相对较大的长宽比、严格的光学限制和光滑的表面，纳米线越来越引起人们对片上光子器件基础研究和技术应用的研究兴趣。这类纳米结构的横截面通常为 2~200 nm，长度可达几微米，可以连接纳米世界和宏观世界。特别是，可以通过端面反射通过具有正反馈的纳米线谐振器建立激光行为，使纳米线成为下一代光电子学的有希望的候选者。因此，在过去的十年中，人们提出并通过实验证明了多种基于纳米线的器件，包括纳米级相干激光器、光学传感器、波导、光开关和光子网络。在本文中，回顾了纳米线制造、激光器、电路和设备方面的重大进展。首先，我们重点介绍了纳米线合成的成就，并介绍了纳米线光学的基础知识。根据腔体配置和模式类别，介绍了由纳米线组成的不同光源。接下来我们回顾一下功能纳米线器件的最新进展和现状。最后，我们提出了我们对纳米线在光子电路中的挑战和未来机遇的看法。