Before you set up the preform, I recommend leak testing the rotary seal. I do this by flowing oxygen through the rotary seal. Start by plugging the end of the rotary seal with a solid quartz tube. Next, lower the regulated O2 pressure to ~ 5 psi, slightly above what the system will see during deposition. Observing the O2 carrier mass flow controller, you will see it go to zero if the system is leak tight. This procedure will leak test the oxygen carrier line throughout the gas system, from input to rotary seal. Taking time to conduct this leak test is worthwhile. If a leak is present in the rotary seal, you can potentially add moisture and/or lose part of the gas stream, which would reduce layer thickness and potentially refractive index. If the leak rate changes during the run, it can result in axial preform variability.
Additional resources from the FOC team include:
- Category Resource FOC Fiber Design and Manufacturing Page
- Glossary, Acronyms, Military Specifications for Connectors: http://bit.ly/2a2EFn8
- Q&A Resource: email technical questions to AskFOC@focenter.com
Have questions about this FOC Tip?
Contact FOC with questions at: (800) 473-4237 / 508-992-6464 or email: FiberOpticCenter@focenter.com and we will respond ASAP.
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- MCVD Tips: 14 ideas to enhance preform strength, yield, and reproducibility
- MCVD Options: These add-on features can enhance your optical fiber preform strength, yield, and reproducibility
- Controlling the optical fiber preform deposition process
- Preparing to Manufacture an Optical Fiber Preform
- Critical Design Goals to Manufacture Optical Fiber Preforms
- Comparing the 2 types of MCVD gas delivery systems to manufacture optical preforms: Stainless steel and Teflon/glass
- Attention specialty fiber manufacturers: Take advantage of FOC’s preform fabrication consulting to troubleshoot your system and achieve reproducibility and high yields