近日，耶路撒冷希伯来大学的Yoav Dana及其研究团队取得一项新进展。经过不懈努力，他们利用三维纳米打印技术制造出独立式微型光子灯笼空间模式(解)多路复用器。相关研究成果已于2024年6月3日在国际知名学术期刊《光：科学与应用》上发表。

据悉，光子灯笼(PL)空间多路复用器在未来的高容量模分复用(MDM)光通信网络，和自由空间光通信等领域具有广阔的应用前景。它们能够在多个单模(SM)源和相同尺寸的多模(MM)波导之间进行有效转换。PL多路复用器通过促进SM阵列空间和单个MM空间之间的绝热跃迁来工作。然而，目前的制造方法迫使这些器件的尺寸达到几毫米，使得与微尺度光子系统的集成相当具有挑战性。3D微纳米打印技术的出现使得制造具有高折射率对比度的独立光子结构(光聚合物-空气)成为可能。

在这项工作中，研究人员引入了一个6模混合，375μm长的PL的设计，制造和表征，它能够实现六个单模输入与一个六模波导之间的有效转换。他们采用了基于遗传算法的逆向设计方法，精确设计PL，并借助商用3D打印机（基于双光子聚合技术）和光聚合物直接在7芯光纤上完成了制造。尽管波导具有高折射率对比度，但值得注意的是，其插入损耗（-2.6dB）、极化相关损耗（-0.2dB）以及模式相关损耗（-4.4dB）均保持在较低水平。

附：英文原文

Title: Free-standing microscale photonic lantern spatial mode (De-)multiplexer fabricated using 3D nanoprinting

Author: Dana, Yoav, Garcia, Yehudit, Kukin, Aleksei, Dallachiesa, Lauren, Guerrier, Sterenn, Fontaine, Nicolas K., Marom, Dan M.

Issue&Volume: 2024-06-03

Abstract: Photonic lantern (PL) spatial multiplexers show great promise for a range of applications, such as future high-capacity mode division multiplexing (MDM) optical communication networks and free-space optical communication. They enable efficient conversion between multiple single-mode (SM) sources and a multimode (MM) waveguide of the same dimension. PL multiplexers operate by facilitating adiabatic transitions between the SM arrayed space and the single MM space. However, current fabrication methods are forcing the size of these devices to multi-millimeters, making integration with micro-scale photonic systems quite challenging. The advent of 3D micro and nano printing techniques enables the fabrication of freestanding photonic structures with a high refractive index contrast (photopolymer-air). In this work we present the design, fabrication, and characterization of a 6-mode mixing, 375μm long PL that enables the conversion between six single-mode inputs and a single six-mode waveguide. The PL was designed using a genetic algorithm based inverse design approach and fabricated directly on a 7-core fiber using a commercial two-photon polymerization-based 3D printer and a photopolymer. Although the waveguides exhibit high index contrast, low insertion loss (-2.6dB), polarization dependent (-0.2dB) and mode dependent loss (-4.4dB) were measured.

DOI: 10.1038/s41377-024-01466-6

Source: https://www.nature.com/articles/s41377-024-01466-6