Siliprandi Jacopo, MacLachlan David G, Ross Calum A, Sharma Tarun K, Labadie Lucas, Madhav Kalaga, Nayak Abani S, Dinkelaker Aline N, Roth Martin M, Scott Nicholas J, du Foresto Vincent Coudé, Thomson Robert R, Benoit Aurélien
Appl Opt. 2024 Jan 1;63(1):159-166. doi: 10.1364/AO.510293.
A fiber-connectorized K-band integrated-optics two-telescope beam combiner was developed for long-baseline interferometry at the CHARA telescope array utilizing the ultrafast laser inscription (ULI) technique. Single-mode waveguide insertion losses were measured to be ∼1.1 over the 2-2.3 µm window. The development of asymmetric directional couplers enabled the construction of a beam combiner that includes a 50:50 coupler for interferometric combination and two ∼75:25 couplers for photometric calibration. The visibility of the bare beam combiner was measured at 87% and then at 82% after fiber-connectorization by optimizing the input polarization. These results indicate that ULI technique can fabricate efficient fiber-connectorized K-band beam combiners for astronomical purposes.
利用超快激光写入（ULI）技术，为位于CHARA望远镜阵列的长基线干涉测量开发了一种光纤连接器化的K波段集成光学双望远镜光束组合器。在2 - 2.3微米窗口内，单模波导插入损耗测量值约为1.1。非对称定向耦合器的发展使得能够构建一种光束组合器，该组合器包括用于干涉组合的50:50耦合器和用于光度校准的两个约75:25耦合器。通过优化输入偏振，裸光束组合器的可见度测量值为87%，光纤连接器化后为82%。这些结果表明，ULI技术可为天文目的制造高效的光纤连接器化K波段光束组合器。
