Riesen Nicolas, Phillips Nicholas, Lancaster David G
Opt Express. 2021 Sep 13;29(19):29982-29995. doi: 10.1364/OE.433541.
Graded-index optical fiber probes suitable for focusing or collimating the output of an optical fiber at a wavelength of 1.3 µm have become an enabling technology in optical coherence tomography imaging applications for in vivo bioimaging. Such fiber tips however remain uncommon in other photonics applications. This paper provides the first numerical study of graded-index fiber tips covering a broad range of wavelengths spanning from the UV to short-infrared. The wavelength dependency and the influence of probe geometry on performance characteristics such as far-field divergence angle, spot size and working distance are analyzed. The paper yields easily accessible design guidelines for the fabrication of collimating or focusing fiber tips. Fiber collimators have considerable potential for use in free-space systems and could benefit a range of devices such as variable attenuators, dynamic wavelength equalisers and large 3D optical cross-connect switches, whereas focusing fiber tips have applications in high-resolution imaging.
适用于在1.3 µm波长下聚焦或准直光纤输出的渐变折射率光纤探头已成为用于体内生物成像的光学相干断层扫描成像应用中的一项使能技术。然而，这种光纤尖端在其他光子学应用中仍然不常见。本文首次对覆盖从紫外到近红外的广泛波长范围的渐变折射率光纤尖端进行了数值研究。分析了波长依赖性以及探头几何形状对远场发散角、光斑尺寸和工作距离等性能特征的影响。本文为制造准直或聚焦光纤尖端提供了易于获取的设计指南。光纤准直器在自由空间系统中有很大的应用潜力，并且可以使一系列设备受益，如可变衰减器、动态波长均衡器和大型3D光交叉连接交换机，而聚焦光纤尖端则应用于高分辨率成像。
