PFS instrument delivers lights of stars and galaxies from the telescope to our spectrographs by a ~60m-long cable of optical fibers. As we presented in the previous post (https://pfs.ipmu.jp/blog/2017/04/p447), the fiber cables were assembled at the factory of PPC Broadband Inc. in UK. Then the cables were shipped to LNA in Brazil for the next step.
If some stress such as tension and compression is applied to a fiber, the quality of the transmitted light gets degraded. To avoid this, we optimized the cable design and the integration process through prototyping. After that, in May 2019, we completed the assembly of 8 cables.
In Brazil, we will “finalize” the fiber cables by integrating fiber connectors and devices to check the condition of the fiber connection, and polishing the fiber tips. To start these finishing works, we had a meeting to review the design and work plan in June. Also, we carried out optical tests of the fibers in the cables before and after the shipment of the cables from UK to Brazil, and confirmed that the fibers are in a very good condition. We will test the fibers in the same way after the work is complete in Brazil, and before and after the cables are installed on the telescope.
Having completed all post-shipment inspections and tests, the Brazilian team has started working on the first cable system out of the four in total. We aim at shipping this first one to Subaru by the end of this year.
Figure 1 (above): Putting the packaged fiber cable into a crate.
Figure 2 (below, 3 photos): Optical test to measure Focal Ratio Degradation of the fibers in the cable.