Vacuum Feedthroughs, Heating Elements, and Custom Thermal Systems for
Aerospace, University Research, Semiconductor, Medical and OEM Applications

Fiber Optic Feedthrough

Fiber Optic Feedthrough


A company contacted BCE to design a fiber optic feedthrough for their new assembly. They required (4) x 100 inch single mode coupler fibers to reach a narrow area within their assembly. The customer had a difficult time finding a compatible solution due to the specific thread type and the long fiber length so they approached BCE to create a custom feedthrough. Due to the sensitive nature of fiber optic cable, a BCE Epoxy Feedthrough was the optimal solution.


  • 4x single mode Acrylate coated fibers
  • ¾”-16 threaded 316 SS fitting
  • Helium leak test: 5 x 10-8 atm-cc/s or better
  • Temperature range: 0°C - 65° C
  • Long lead length ~100”


The small outer diameter (245 µm with an 8 µm core) of the fibers and the long length, required the addition of Hytrel furcation tubing to prevent breakage by reducing the bend radius. This created a robust feedthrough to withstand a wide range of vacuum and temperature conditions. The fiber optic feedthrough exceeded expectations and achieved a 10 x 10-10 atm cc/s helium leak rate.


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