Department of Electrical Engineering, Polytechnique Montreal, University of Montreal, Montreal, QC H3C 3A7, Canada.
Department of Engineering Physics, Polytechnique Montreal, University of Montreal, Montreal, QC H3C 3A7, Canada.
Sensors (Basel). 2023 Jan 26;23(3):1398. doi: 10.3390/s23031398.
High-performance erbium-doped DFB fiber lasers are presently required for several sensing applications, whilst the current efficiency record is only a few percent. Additionally, a flat-top intra-cavity power distribution that is not provided in traditional DFB lasers is preferred. Moreover, cavity lengths of <20 cm are attractive for fabrication and packaging. These goals can be achieved using highly erbium-doped fiber (i.e., 110 dB/m absorption at 1530 nm), providing high gain with proper engineering of coupling coefficients. In this paper, for a given background fiber loss, first the optimum intra-cavity signal powers for various pump powers are numerically calculated. Then, for a fully unidirectional laser, optimum coupling profiles are determined. Design diagrams, including contour maps for optimum cavity lengths, maximum output powers, maximum intra-cavity signal powers, and quality factors considering various pump powers and background fiber losses, are presented. The laser pump and intra-cavity signal distribution are also calculated for a realistic, feasible modified coupling profile considering a strong unidirectionality. The DFB laser is finally simulated using generalized coupled-mode equations for such modified profiles. The efficiency of more than 22% can be realized, which is the highest reported for DFB lasers based only on erbium-doped fiber.
目前，需要高性能掺铒分布式反馈（DFB）光纤激光器来满足几种传感应用的需求，而当前的效率记录仅为百分之几。此外，优选在传统 DFB 激光器中未提供的平顶腔内功率分布。此外，对于制造和封装来说，长度<20cm 的腔长是吸引人的。通过使用高掺铒光纤（即在 1530nm 处具有 110dB/m 的吸收）可以实现这些目标，通过适当的耦合系数设计可以提供高增益。在本文中，针对给定的背景光纤损耗，首先数值计算了各种泵浦功率下的最佳腔内信号功率。然后，对于完全单向的激光器，确定了最佳的耦合轮廓。给出了考虑各种泵浦功率和背景光纤损耗的最佳腔长、最大输出功率、最大腔内信号功率和品质因数的设计图，包括轮廓图。还计算了考虑强单向性的实际可行的改进耦合轮廓的激光泵浦和腔内信号分布。最后，针对这种改进的轮廓，使用广义耦合模方程对 DFB 激光器进行了模拟。可以实现超过 22%的效率，这是仅基于掺铒光纤的 DFB 激光器报告的最高效率。
