AFL Blog - Problems Solved: The 4 Key ?Whys? of AFL?s Metal-coated Fibers

By Danielle Phillips, Marketing Commuication Specialist at AFL
Metal-coated optical fibers have been around for years. These are necessary for high-temperature applications such as supercritical geothermal wells, high-temperature oil and gas downhole sensing and downstream oil processing, where temperatures over 300⁰C are common. Unfortunately, most commercially-available, metal-coated fibers have four key problems.
With an operating temperature range from -65°C up to 500⁰C, AFL’s VHT500 Single-mode Series and VHT5000 Multimode Series fibers address these challenges:
1. Low attenuation. While the attenuation of most metal-coated fibers is inherently high (10-20 dB/km), AFL’s VHT metal-coated fibers reduce that attenuation by 50-75%, seeing less than 5 dB/km at the most frequently used wavelengths.
2. Temperature cycling attenuation differences. Typical metal-coated fibers exhibit large attenuation differences when they are temperature cycled. VHT500 and VHT5000 fibers see some attenuation changes, but the attenuation difference is small enough that standard sensing equipment can tolerate the changes with ease.
3. Cold welding prevention. A frustrating challenge of metal-coated fibers is “cold welding” to itself or to metal tubing. AFL applies a proprietary treatment to the VHT fibers which prevents them from sticking to a metal tube, or to other metal fibers contained in the tube.
4. Longer length production. AFL has routinely produced lengths of metal-coated fibers up to 5 km, which is over five times the length of other gold-coated fibers on the market.
If you are facing any of these challenges with metal-coated fibers, contact us about the VHT500 Single-mode Series and VHT5000 Multimode Series fibers. Let our team help determine the best product for you.