GEO50-H Geophysical Graded-Index Optical Fiber - Hydrogen Resistant, Silicone/PFA

Product Description

This optical fiber is designed for distributed temperature sensing and communications in applications where hydrogen diffusion is a concern, and
at elevated temperatures for long duration exposure. The waveguide features a proprietary, hydrogen insensitive core structure to minimize the effects of
hydrogen darkening, and also features a triple-layer coating system. The innermost layer is a thin carbon layer that reduces stress-fatigue by ensuring that no water can attack the surface of the silica cladding. A secondary layer of enhanced silicone dampens attenuation-inducing compressive forces and is easily strippable while the teritiary layer of PFA provides excellent chemical and abrasion resistance and low water absorption. This combination is suitable for long-term use up to 200 ºC (~ up to 20 years, performance and reliability will vary depending on installation environment. Consult OFS for guidance). In addition, this fiber structure is ideal for low temperature and cryogenic applications, operating indefinitely at low temperatures.
Unit of Measure



N/A Multimode Graded-Index

Short-Term Bend Radius

N/A ≥ 8 mm

Long-Term Bend Radius

N/A ≥ 10 mm

Features and Benefits

Improved Waveguide Resists Hydrogen DarkeningMinimizes permanent losses due to hydrogen ingression in harsh conditions
Graded-Index 50/125 Fiber StructureCompatible with most commercially available Distributed Temperature Sensing (DTS) interrogators; can also be fusion spliced to similar hydrogen insensitive core optical fiber, and traditional lead-in optical fibers
Carbon/Silicone/PFA Coating SystemLow friction, outer coating resists chemicals, abrasion and water absorption and is easy to mechanically strip


N/A OFL @ 850 nm: ≥ 400 Mhz-km
OFL @ 1300 nm: ≥ 400 Mhz-km

Optical Properties

Operating Wavelength

N/A 850/1300 nm


N/A @ 850 nm: ≤ 4.0
@1300 nm: ≤ 2.0 dB/km

Numerical Aperture (Nominal)

N/A 0.20

Dimensions/Geometric Properties

Core Diameter (Nominal)

N/A 50 ± 3 µm

Clad Diameter

N/A 125 ± 1 µm

Clad Non-Circularity

N/A ≤ 2.0%

Coating/Buffer Descriptions

Coating Material

N/A Silicone/PFA

Operating Temperature

N/A -55 to +200 ºC

Mechanical and Testing Data

Proof Test Level

N/A 200 kpsi1.38 GPa