SBIR Phase I: Phase Locking of High Power Fiber Laser Arrays

这份小型企业创新研究第一阶段提案介绍了一种创新的想法，即从包层泵浦的多芯光纤激光器阵列中产生非常高亮度的激光，该阵列嵌入具有独特的“等距”结构的普通低损耗包层中。在很低损耗的包层区域，光纤芯之间很强的逝去波耦合可以为基模提供最高的模式增益。介绍了一种可靠制造等距多芯光纤阵列的技术。建立了计算等距环形多芯光纤激光器阵列远场辐射方向图的计算机模型。结果表明，在V值为2、芯距为芯径1.5倍的单相等距多芯锁相光纤激光器列阵中，可以获得幅度比旁瓣大40d B的远场高亮度、衍射限光束。然而，在第一阶段需要解决的剩余问题是，在什么条件下可以保持稳定的单相振荡。在第一阶段-SBIR中，已经确定了四项任务，目的是定量地确定所有激光参数和工作条件，以便从锁相包层泵浦的光纤激光器阵列中建立稳定的超模激光振荡。这一阶段的结果对第二阶段的后续工作至关重要，以构建和演示高度可信的锁相光纤激光器阵列。

This Small Business Innovation Research Phase I proposal introduces an innovative idea to generate a very high brightness laser beam from a clad-pumped multicore fiber laser array embedded in a common low loss cladding with a unique 'isometric' structure. In a very low-loss cladding region, very strong evanescent-wave coupling among the fiber cores can provide the highest modal gain for the fundamental supermode. A technique has been introduced to reliably manufacture the isometric multicore fiber arrays. A computer model has been developed to calculate the far-field radiation patterns emitting from multicore fiber laser arrays arranged in isometric rings. Results indicate that a high brightness, diffraction limited laser beam in the far-field with an amplitude 40dB greater than the side lobes, can be obtained from isometric multicore phase locked fiber laser array in uni-phase with a V-value of 2 and a core separation of 1.5 times the core diameter. However, the remaining issues that need to be addressed in Phase I, are the conditions under which a stable oscillation can be maintained in uni-phase. Under the Phase I-SBIR, four tasks have been identified for the purpose of determining quantitatively all laser parameters and operating conditions for the establishment of a stable laser oscillation at the fundamental supermode from a hase-locked, clad-pumped fiber laser array. The results of this Phase I are crucial for the Phase II follow-on to construct and demonstrate a phase-locked fiber laser array with a high degree of confidence.