Fiber Design and Manufacturing
Preform Fabrication Consulting Services
Fiber Optic Center, Inc. (FOC) offers preform fabrication consulting services to manufacturers of specialty optical preforms and fibers. Included is guidance selecting the right MCVD fabrication system for your needs, post-installation troubleshooting to meet exacting product specs, developing custom solutions, training personnel, and writing standard operating procedures (SOPs)
A unique and particularly valuable service at FOC is Larry Donalds’ troubleshooting expertise to overcome the many preform fabrication and fiber draw issues manufacturers face when producing specialty optical fibers. Larry’s consulting includes guidance selecting the right MCVD fabrication system for your needs, post-installation troubleshooting to meet exacting product specs, developing custom solutions, training personnel, and writing standard operating procedures (SOPs).
- Preparing to Manufacture an Optical Fiber Preform
- Critical Design Goals to Manufacture Optical Fiber Preforms
- Attention specialty fiber manufacturers: Take advantage of FOC’s preform fabrication consulting to troubleshoot your system and achieve reproducibility and high yields.
- Comparing the 2 types of MCVD gas delivery systems to manufacture optical preforms: Stainless steel and Teflon/glass
- What documentation have you published on how operators can better meet design goals?
- Specialty optical preforms strength and deposition issues
- Chemical level changes in gas delivery system bubbling process
- We are having issues with shrinkage and are focusing on the polish step. Looking for some steps, best practices, solutions, etc.
- Will properly cleaning the tube and extension tube in the quartz tube cleaning process increase fiber strength during deposition?
- Our deposition tube diameter varies from run to run. Do you have information on how to control that?
- Do you have tips for those having difficulty achieving straight preforms?
- Do you have any information on quartz tube-cleaning process best practices?
- Can deposition temperature cause absorption in final fiber measurements?
- We are experiencing runout while rotating the lathe. How do you handle getting the runout under control?
- Does initial tube straightening minimize runout? Do you have SOPs available on this?
- How critical is calibration to reproducible design goals of optical fiber preforms?
As we all know, the internal temperature of the deposition tube is what matters, since the reaction is occurring on the inside. However, the process pyrometer is reading the external temperature. SG Controls offers a diameter control system, which controls and provides an optical measurement of the tube. This system is closed loop, with the pressurization system controlling tube back pressure with feedback from the diameter measurement and set-point. Having an automated system to control tube diameter is very important. While I’ve had some success controlling diameter manually, that approach is not nearly as reproducible as an automated system.
As you probably know, you can add dopants such as phosphorous and fluorine to reduce the deposition temperature.
Hand-held Pyrometer Tip
You do not need to purchase an expensive blackbody unit. Instead, purchase a hand-held standard that is calibrated with a blackbody standard. In addition, you could temporarily mount the hand-held pyrometer on the fire carriage to spot-check the process pyrometer calibration.
Preform Tip (keeping the preform straight during collapse)
Companies like SG Controls offer stainless-steel, water-cooled burners with nitrogen curtains to reduce the hot zone width, which prevents preform sagging during collapse. Adjustable flow nitrogen jets on the outside edges of the burner blow against the tube to uniformly reduce the hot zone width. This allows the operator to adjust the hot zone width during collapse. This piece of equipment can enhance uniformity and fiber yields.
About Larry Donalds
Larry Donalds is Business Development, Fiber Design and Manufacturing, bringing more than 35 years of experience from 3M Company in St. Paul, MN, after recently retiring. During his time with 3M Company, he spent 24 years in the development and manufacture of specialty optical fiber utilizing “voice of the customer,” helping 3M design and produce optical fibers to meet specific customer applications and performance criteria.
Projects included the development and production of PM, PZ, EDFA (Erbium Doped Fiber Amplifier) fiber, radiation-hardened fiber for gyroscopes, solution doping of preforms, patent development for Oxyfluoride Erbium fiber, organometallic rare earth deposition and a rare earth single mode fiber bend and position sensor.
In his fiber position at 3M, Larry maintained and operated MCVD equipment from SG Controls Ltd of Cambridge, England, whom FOC has represented in North America for over 25 years. Larry has achieved several awards during his career including 3M Golden Step Award, Photonics Circle of Excellence Award, R&D 100 Award, 3M Circle of Technical Excellence Awards in 1983, 2001 and 2008 and the 3M Ideation Challenge award in 2017.