多芯光纤折射率与内应力分布重构技术（特邀）

介绍了一种基于定量相位显微（Quantitative phase microscopy，QPM）法、Brace-K?hler补偿器（Brace-K?hler compensator，BKC）法与机器视觉技术的多芯光纤综合参数测试系统，并利用该系统获得了七芯光纤的折射率分布与几何结构，单模光纤的内应力分布图。采用横向测量方式的QPM法避免了截断光纤造成的损坏，采用改进的BKC法优化了光延迟量的获取方式，结合机器视觉技术，实现了多模块、高空间分辨率、快速准确的光纤参数测量，其中相对折射率差的精度约5×10?4量级，单模光纤内应力测量分辨率约0.5 MPa。通过与既有的光纤产品技术指标对比，证明了该系统具有测量准确性，测试结果为多芯光纤在传输和传感等多领域的应用提供了数据支撑。

Reconstruction technology of refractive index and internal stress distribution of multi-core fibers (Invited)

A novel multi-core fiber comprehensive parameter test system based on quantitative phase microscopy method, Brace-K?hler compensator method and machine vision technology was introduced. In order to characterize the test capability of peoposed system, the refractive index distribution and geometric structure of a seven-core fiber from YOFC, and the internal stress distribution of a single-mode fiber from Corning were obtained by this system, respectively. According to the former research, the quantitative phase microscopy method using transverse measurement could avoid the performance ?damage ?caused ?by ?truncated ?optical fiber?efficiently.?The?improved?Brace-K?hler?compensatormethod ?was ?used ?to ?optimize ?the ?acquisition ?to ?get ?the optical delay. ?Combined ?with ?the ?machine ?vision technology, ?the ?system ?realized ?multi-modules, ?high spatial ?resolution, ?fast ?and ?accurate ?fiber ?parameter measurement. After sample processing, program debugging and optimization, the experiment results show that?the?accuracy?of?relative?refractive?index?differencein multicore?fiber?was?about?5×10?4?magnitude?and?the?internal stress ?measurement ?resolution ?of ?single-mode ?fiber ?wasabout ?0.5?MPa. ?The ?comparison ?with ?the ?technicalindicators?of?existing?optical?fiber?products?proves?that?the system ?has ?measurement ?accuracy, ?and ?the ?test ?results provide ?data ?support ?for ?the ?application ?of ?multi-core fibers?in?multiple?fields?such?as?transmission?and?sensing.