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--- fiber_run [2024/09/11 21:30] – holtz
+++ fiber_run [2026/05/26 15:45] (current) – 24.4.246.2
@@ Line 14: / Line 14: @@
 the same spool for the Australia SONG node a few years ago, they looked up the notes for that, and found that the technician who handled that fiber described it as "devil fiber", so it perhaps had the same issues back then. They did not recall doing FRD testing at the time. If FRD was not tested, this perhaps might have implications for performance at the Australia node.
-As of September 2024, we are considering how to proceed.
+Because of this, we decided not to proceed with the octagonal fiber for the full run. However, Fiber Tech Optica has developed a method of fusing fiber together with apparently good success. Based on their test results, we decided to proceed by fusing a short section of the octagonal fiber to a long section of circular fiber, in order to maintain scrambling. Unfortunately, 50 micron circular fiber was not readily available in the lengths required at the time. As a result, we decided to proceed with a long run of 53 micron circular fiber. At the telescope end, FTO fused a short section of the 50 micron octagonal fiber, and in front of that,  short section of 50/125 circular fiber for a good match in the FC connector at the telescope.
+The cable has three fibers that are terminated in a ferrule at the spectrograph end, and are separated into three individual fibers with FC connectors at the telescope end. Two full fibers were constructed by FTO. FTO provided a {{::fiber:final_report_pf_02_compressed_1_.pdf|test report}} on these two cables; the first one that the constructed had poorer performance than the second one. At APO, we pulled the better one through the conduit, and the other one has remained on its spool.