EVacuAted OptiCal Fibres for Ultimate UV-to-Infrared Light TransMission (VACUUM)

用于终极紫外到红外光传输（真空）的真空光纤

• 批准号: EP/W037440/1
• 负责人: Radan Slavik
• 金额: $ 109.6万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW037440%2F1
• 关键词: EVacuAted; OptiCal; Fibres; Ultimate; UV

Over the last four decades, optical fibres have revolutionised telecommunications and enabled Internet as we know it today. Sensing is another area where optical fibres are used, for example for monitoring engineering structures (e.g., strain and vibration along bridges, tunnels, etc.), or to deliver light for advanced instruments such as next-generation microscopes that can see material/tissue properties that are invisible with traditional instruments. Optical fibres are also leading a revolution in manufacturing by generating and delivering intense laser light capable of welding and cutting.However, conventional fibres, where light propagates through glass, cannot cope with such high powers due to the onset of nonlinear effects and material damage caused by the high light intensities. Glass absorption also limits the exploitation of fibre technologies in the visible and near/mid-infrared. These shortcomings are being addressed by the next generation of optical fibres, so-called hollow-core fibres that guide light through a central hole, thus avoiding significant light-glass interaction. Light in these fibres is guided thanks to a specially engineered glass microstructure built around a central hole. Recently, the design and manufacturing of this microstructure has been improved significantly and hollow-core fibres are now emerging with properties that surpass those of traditional fibres in almost every regard. In these novel fibres, light propagates through the core; in most cases the core contains air which enters the fibre during fabrication or onward handling. Although light interacts with air significantly less than with glass, this interaction nevertheless still imposes appreciable limitations. One example is absorption at wavelengths such as 1300 nm (due to water vapour) or in the mid-infrared (absorption of atmospheric gases). Another example relates to the transmission of high-power pulses (e.g., as needed for laser based welding) where nonlinear optical interactions with the air result in significant beam distortions. The ultimate solution would be to evacuate the fibre core, thereby eliminating the air-light interaction. Preliminary calculations show that evacuating a long length of hollow-core fibre (kilometres) would take impractically long (years) due to the small core diameter (typically ~0.03 mm). Techniques to characterize the gas pressure or content along the fibre length have also not been developed yet. Without such measurements, it is difficult to monitor the evacuation process, or to validate models that describe the evacuation process. This project is dedicated to investigating, theoretically and experimentally, techniques to accurately characterize the (residual) air pressure along a length of hollow-core fibre. Subsequently, we will research several solutions to reliably evacuate them over long lengths and to seal them while enabling low loss coupling of light in and out. Finally, we will demonstrate how these improved hollow-core fibres will enable next-generation applications, targeting three selected areas:1) telecommunications, where evacuation will enable communication over a large wavelength range, increasing several times how much data can be transmitted over a given time. 2) high-power laser pulses for welding/drilling/mining, but also bio-medical imaging, where we expect up to 100-1000 times larger powers to be deliverable through the evacuated hollow-core fibres as compared to air-filled ones and up to one million times more than with today's glass-core fibres. 3) transmission of mid-infrared light ("molecular fingerprint region") and demonstration of applications in remote hydrocarbon analysis, of interest, e.g., in oil wells. Evacuated hollow-core fibres will offer superior performance to any other fibre technology, ranging from guiding in the UV all the way to mid-infrared, opening new opportunities in science, technology, and applications.

在过去的四十年里，光纤彻底改变了电信，使我们今天所知道的互联网成为可能。传感是使用光纤的另一个领域，例如用于监测工程结构（例如，桥梁，隧道等的应变和振动），或为先进仪器（如下一代显微镜）提供光，这些仪器可以看到传统仪器无法看到的材料/组织特性。光纤还通过产生和输送能够焊接和切割的强激光，引领了制造业的一场革命。然而，由于高光强引起的非线性效应和材料损伤，光通过玻璃传播的传统纤维无法应对如此高的功率。玻璃的吸收也限制了可见光和近红外/中红外纤维技术的开发。下一代光纤正在解决这些缺点，即所谓的空心芯光纤，它引导光通过中心孔，从而避免了明显的光-玻璃相互作用。由于在中心孔周围建造了一个特殊的工程玻璃微结构，这些纤维中的光被引导。最近，这种微结构的设计和制造有了显著的改进，空心纤维在几乎所有方面的性能都超过了传统纤维。在这些新型纤维中，光通过核心传播；在大多数情况下，芯中含有空气，空气在制造或后续处理过程中进入纤维。尽管光与空气的相互作用明显小于与玻璃的相互作用，但这种相互作用仍然存在明显的局限性。一个例子是吸收波长如1300纳米（由于水蒸气）或中红外（吸收大气气体）。另一个例子涉及高功率脉冲的传输（例如，激光焊接所需的），其中与空气的非线性光学相互作用导致明显的光束畸变。最终的解决方案是疏散纤维芯，从而消除空气-光相互作用。初步计算表明，由于芯直径较小（通常约0.03毫米），疏散一长段空心芯纤维（公里）将需要很长时间（年）。沿着纤维长度表征气体压力或含量的技术也尚未开发。没有这样的测量，很难监控疏散过程，或验证描述疏散过程的模型。该项目致力于从理论上和实验上研究技术，以准确表征沿空心芯纤维长度的（残余）空气压力。随后，我们将研究几种解决方案，以可靠地长时间疏散它们，并密封它们，同时实现低损耗的光进出耦合。最后，我们将展示这些改进的空心芯光纤将如何实现下一代应用，针对三个选定的领域：1)电信，其中疏散将实现大波长范围内的通信，在给定时间内可以传输的数据量增加几倍。2)用于焊接/钻孔/采矿的高功率激光脉冲，以及生物医学成像，我们预计通过真空空心芯光纤提供的功率将比充气光纤高100-1000倍，比目前的玻璃芯光纤高100万倍。3)中红外光的传输（“分子指纹区”）和在远程烃分析中的应用演示，例如在油井中。真空中空纤维将提供比任何其他纤维技术优越的性能，从引导紫外线一直到中红外，在科学、技术和应用方面开辟了新的机会。

项目成果

Support-Free Thermally Insensitive Hollow Core Fiber Coil

• DOI: 10.1109/jlt.2023.3241255
• 发表时间: 2023-05
• 期刊: Journal of Lightwave Technology
• 影响因子: 4.7
• 作者: Xuhao Wei;A. Taranta;Bo Shi;Meng Ding;Zitong Feng;D. Richardson;F. Poletti;R. Slavík

Direct and low-loss connection between a hollow-core optical fiber and a dispersion compensating fiber for dispersion-free delivery of short optical pulses in hollow-core fiber

空心光纤和色散补偿光纤之间的直接低损耗连接，用于在空心光纤中无色散传输短光脉冲

• DOI: 10.1117/12.2648720
• 发表时间: 2023
• 作者: Zhong A

Interconnectivity between effectively single-moded antiresonant hollow core fibres and conventional single-mode fibres

• DOI: 10.1016/j.yofte.2023.103541
• 发表时间: 2023-12
• 期刊: Optical Fiber Technology
• 影响因子: 2.7
• 作者: Radan Slavík;M. Komanec;E. N. Numkam Fokoua

All-fiber hollow-core fiber gas cell

• DOI: 10.1016/j.yofte.2023.103513
• 发表时间: 2023-12
• 期刊: Optical Fiber Technology
• 影响因子: 2.7
• 作者: D. Suslov;M. Komanec;T. Kelly;Ailing Zhong;Stanislav Zvánovec;Francesco Poletti;N. Wheeler;Radan Slavík

Distributed Characterization of Low-loss Hollow Core Fibers using EDFA-assisted Low-cost OTDR instrument

使用 EDFA 辅助的低成本 OTDR 仪器对低损耗空心光纤进行分布式表征

• DOI: 10.23919/ofc49934.2023.10117143
• 发表时间: 2023
• 作者: Wei X