Wu Yan, Wen Jianxiang, Lu Yinghui, Pang Fufei, Tang Fengzai, West Geoff, Wang Tingyun
Opt Lett. 2024 Oct 15;49(20):5691-5694. doi: 10.1364/OL.533911.
Vortex beams carrying orbital angular momentum (OAM) offer a solution for enhancing spatial degrees of freedom, particularly in conjunction with wavelength division multiplexing, which can significantly boost data capacity for optical communication. Addressing the increasing demand for high information-carrying capacity, we present a dynamically tunable OAM laser source in this study. We demonstrate a ring-cavity vortex fiber laser employing intra-cavity mode conversion through a helically twisted high-absorption few-mode erbium-doped fiber (HA-FM-EDF). The constructed vortex fiber laser exhibits wavelength switchability via an integrated Sagnac loop, facilitated by a homemade ring-core fiber. Furthermore, topological-charge tunability is achieved through the utilization of twisted HA-FM-EDF with varying helical pitches. To our knowledge, this marks the first successful implementation of two-dimensional multiplexing of wavelength and OAM in a vortex fiber laser. The OAM laser serves as a versatile vortex source with high tunability and flexibility, holding significant potential for deployment in ultrahigh-speed/ultrahigh-capacity communications, ultrahigh-resolution imaging, and ultrahigh-sensitivity sensing applications.
携带轨道角动量（OAM）的涡旋光束为增强空间自由度提供了一种解决方案，特别是与波分复用相结合时，这可以显著提高光通信的数据容量。为了满足对高信息承载能力日益增长的需求，我们在本研究中提出了一种动态可调谐的OAM激光源。我们展示了一种环形腔涡旋光纤激光器，它通过螺旋扭曲的高吸收少模掺铒光纤（HA-FM-EDF）进行腔内模式转换。所构建的涡旋光纤激光器通过集成的萨格纳克环实现波长可切换性，这得益于自制的环形芯光纤。此外，通过使用具有不同螺旋节距的扭曲HA-FM-EDF实现了拓扑电荷可调谐性。据我们所知，这标志着在涡旋光纤激光器中首次成功实现了波长和OAM的二维复用。该OAM激光器作为一种具有高可调谐性和灵活性的通用涡旋源，在超高速/超高容量通信、超高分辨率成像和超高灵敏度传感应用中具有巨大的部署潜力。
