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Harsh Environment fiber

Harsh Environment Optical Fibers 

Harsh environment optical fibers are designed for use at elevated temperatures and pressures in aggressive chemical environments. Typical applications include the oil & gas and geothermal industries, where the fibers are used for real-time downhole temperature and pressure measurements, data transmission, acoustic, seismic and imaging applications. AFL's Verrillon® harsh environment fibers are manufactured with a wide range of polymeric coatings including Polyimide, Silicone, Silicone-PFA and High Temperature Acrylates. In addition, our Verrillon optical fibers are available with a hermetic coating that prevents hydrogen, moisture and acid ingression. The fibers are suitable for operation over a wide range of temperatures from cryogenic up to 500ºC, depending on the coating combination selected. They are also available in a variety of different waveguide designs, including Multimode, Single-mode, Pure Silica Core, Bend-Insensitive and custom profiles.

Carbon Coating Technology: The Ultimate Barrier to Hydrogen Diffusion

AFL’s Verrillon hermetically-sealed optical fibers have been successfully deployed in downhole applications worldwide. The unique composition and method of manufacturing of our carbon coating make it the most reliable barrier against hydrogen for temperatures exceeding 150°C. Our online monitoring system ensures the integrity of the carbon layer throughout the entire length of the fiber. Additionally our state-of-the-art hydrogen testing facility simulates well conditions and provides performance predictions for our customers.

Glass Technology: The Ultimate Resistance to Hydrogen Darkening at High Temperatures

With the development of emerging monitoring technologies such as temperature, pressure, strain, flow, seismic and acoustic, the need for optical fibers and cables that withstand high temperatures (300ºC or higher) and high partial pressures of hydrogen in downhole environments increased dramatically.

Our approach to the high temperature, high hydrogen partial pressures is to modify the glass composition of the optical fiber core to make it inherently resistant to hydrogen attack. This research culminated in the VHM5000 Series of fibers that are completely immune to hydrogen-induced loss. The Verrillon® VHM5000 technology is the result of a uniquely optimized glass design that is exclusively available from AFL.


What makes Verrillon® fiber so reliable?

  • Best-in-class hermetic coating ensures that the fiber is highly resistant to molecular hydrogen, water and corrosive chemicals
  • Proprietary glass chemistry designs enhance hydrogen resistance and reduce darkening showing negligible loss after extended exposure to hydrogen
  • The industry’s broadest range of specialized coatings allow fibers to maintain their reliability from cryogenic temperatures up to 500°C
  • Quality control and product certification using proprietary online real-time monitoring technique ensure uniform fiber hermeticity throughout continuous, proof-tested lengths exceeding 20 kilometers
  • Large variety of waveguide designs include multimode graded and step-index, single-mode, pure silica core and custom index profiles


Verrillon® VHM5000 Series Graded-Index (GI) multimode optical fibers feature unique glass chemistry that is designed to perform in hydrogen-rich severe downhole environments. VHM5000 is the best high-temperature hydrogen-resistant fiber in the world. Tens of mega-meters of Verrillon VHM5000 fibers have been successfully deployed in extremely harsh environments over the last two decades.
Verrillon VHT500 is a pure silica core single-mode design with a protective metal coating that allows it to operate at temperatures up to 500°C. Typically, these fibers are used in down-hole data logging for enhanced supercritical geothermal applications, hightemperature oil/gas downhole monitoring using acoustic, strain and temperature sensing, and downstream oil process monitoring.
Traditional fiber coating offering includes materials rated to 150°C (MTDA), 200°C (SPFA) and 300°C (Polyimide).
AFL's Verrillon VHM7000 Series graded-index, bend-insensitive multimode fiber is suitable for mid-range temperatures where the carbon coating is a true barrier against hydrogen diffusion that causes undesirable optical absorption in the operating spectral region of most optical sensors. It has the added benefit of low bend loss for use in extremely tight bend applications.
Verrillon® Harsh Environment VHM4000 Series is a family of Step-Index (SI) multimode fibers with excellent resistance to hydrogen darkening at high temperatures and pressures. These SI fibers are suitable for applications where moderate lengths of fiber are required and where hydrogen is present in high concentrations. VHM4000 fibers are available in 50/125 and 62.5/125 micron designs.
Verrillon® VHM3000 Series of Graded-Index (GI) multimode optical fibers are suitable for high temperature applications up to 300°C in hydrogen containing environments. The high bandwidth of these fibers allows Distributed Temperature Sensing (DTS) systems to achieve extremely short spatial resolution in multi-kilometer deep/long deployments.
Verrillon® VHM2000 Series graded-index multimode fiber is suitable for mid-range temperatures where the carbon coating is a true barrier against hydrogen diffusion that causes undesirable optical absorption in the operating spectral region of most optical sensors.
Verrillon® VHS700 is an Ultra-Low Bend Sensitivity, harsh environment, hermetically-sealed single-mode optical fiber. It is compatible with standard dual-wavelength (1310/1550 nm) single-mode fiber, with the added benefit of ultra-low bend loss for use in tight bend applications and demanding cable structures. VHS700 is available in all Verrillon’s harsh environment coatings.
Verrillon® VHS500 is a Pure Silica Core Single-mode Fiber with an entirely fluorinated cladding for superior bend performance and excellent resistance to hydrogen darkening at elevated temperatures. This 1550 nm operating design is available with all Verrillon harsh environment coatings including our renowned hermetic carbon technology. In addition, VHS500 is available with metallic coatings rated to 500°C (VHT500 Series).
Verrillon® VHS300 Series is a Pure Silica Core Single-mode Fiber designed to operate at both 1310 and 1550 nm wavelengths in environments where high temperatures and high concentrations of molecular hydrogen affect the optical performance of standard single-mode fibers.
Verrillon® VHS100 Series Single-mode Fibers, combined with our hermetic carbon coating are suitable for mid-range temperature applications where free hydrogen, water and corrosive chemicals are present. These fibers are compatible with standard single-mode fiber and operate at both 1310 and 1550 nm.
VHS100-HiNA Series is a family of small form factor (SFF), bend-insensitive, reduced cladding single-mode fibers designed for harsh environment small packaging applications where tight bend and hydrogen resistance are key requirements.
Verrillon Harsh Environment Fibers from AFL are available in a wealth of designs. The VHT5000 product is a multimode graded-index optical fiber with optimized glass chemistry for high resistance to hydrogen darkening, coupled with a metal coating that allows the fiber to perform at temperatures up to 500°C.

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Verrillon Optical Fiber

Margaret Sullivan

+1 (508) 890-7113