1 Specialty Optic Fiber © 2020, AFL, all rights reserved. PP-6-00025, Revision 0, 1.29.20 Specifications are subject to change without notice. AFLglobal.com | 800.235.3423 Features • Best glass resistance to hydrogen at high temperatures and pressures available in the entire industry • High bandwidth 50/125 graded-index multimode design for extremely short spatial resolution in sensing applications • Metal coating protects the fiber at temperatures up to 500°C • Patent-pending process prevents fibers from “cold bonding” to metal tubes or other metallic-coated fibers • Suitable for use in high pressure, high temperature and corrosive environments • Available in long lengths (multi-kilometers) • Industry-standard 125 μm clad diameter • Extensive test and measurement data for optical fiber performance under "harsh conditions" provided with fiber VHT5000 Multimode Series 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 well at temperatures up to 500°C. Typically, these fibers are used in down-hole data logging for enhanced supercritical geothermal applications, high-temperature oil/gas downhole sensing and in downstream oil processing. Specifications PART NO. VHM-50-4-CM-125-4 Description Ultra-High temperature metal-coated Graded-Index Multimode fiber with low-loss suitable for use up to 500°C. Available in multi-kilometer continuous lengths and proof-tested at 50 kpsi. PARAMETER VALUE Material Core Silica-based Cladding F-doped Silica Coating Carbon / Metal Geometry Core Diameter (μm) 50 ± 2.5 Clad Diameter (μm) 125 ± 2 Core Non-Circularity (%) ≤ 5 Clad Non-Circularity (%) ≤ 1 Core/Clad Offset (μm) ≤1.5 Coat Diameter (μm) 131 +5 / -2 Optical NA (nominal) 0.2 Attenuation @ 850 nm (dB/km) Attenuation@ 1300 nm (dB/km) ≤ 5 ≤ 5 Bandwidth @ 850 nm (MHz*km) Bandwidth @ 1300 nm (MHz*km) ≥ 300 ≥ 300 Mechanical Prooftest (kpsi) ≥ 50 Operating Temperature (°C) -65 to +500 Continuous Length Available Multi-kilometers