It’s essential to program the PID to maintain tube temperature to the desired set-point while avoiding undershoot/overshoot. Here’s an example of an undershoot/overshoot oscillation. Let’s say you set the temperature at 1700 degrees C, but the PID is not optimized. When the temperature drops to 1699 degrees C, the PID increases hydrogen flow. The temperature climbs to 1710 degrees. The PID reacts by reducing hydrogen. Now the temperature plummets to 1690 degrees. The differential gap has widened, with severe temperature swings. A quality PID that is properly programmed will tightly control the deposition temperature along the entire preform length. To achieve consistency and reproducibility along the preform length, I recommend a tight control of +/-1 to 2 degrees C.
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.
Additional articles from our preform fabrication consultant include:
- 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