Protect, guide, and connect with precision-engineered FIMT designed for fiber optic systems that perform in the most demanding environments — from deep-sea exploration to global communications.
Protection You Can Rely On
K-Tube designs and manufactures fiber-filled metal tubing that delivers reliable protection in environments where pressure, heat, vibration, and corrosion are part of the job. Our engineering team helps you select the right alloys, optimize performance, and build assemblies suited to your application.
Where there are fiber optics, there’s precision protection.
If it carries data, power, or light, K-Tube can help you protect it.
Common applications include:
- Downhole energy systems
- Subsea umbilicals and tow cables
- Seismic monitoring assemblies
- Telecommunications cables
- Industrial sensing and control systems
Select the Right Tube Materials for Your Fiber Optic Assemblies
K-Tube manufactures fiber-filled metal tubing in 304 stainless steel, 316L stainless steel, and Inconel® 625. Each alloy offers distinct performance characteristics for pressure, heat, vibration, and corrosion resistance. Our engineers help you match the material to the demands of your environment.
Available Alloys
- 304 Stainless Steel – general-purpose corrosion resistance
- 316L Stainless Steel – enhanced resistance for subsea and chemical exposure
- Inconel® 625 – high-temperature, high-strength protection
Optical Fiber Options
K-Tube can accommodate a wide range of fiber types used in energy, telecom, sensing, and industrial systems.
| Fiber Type | Specification | Tensile Rating | Temperature Rating |
|---|---|---|---|
| Single Mode | Corning SMF-28e+ | 100/200 KPSI | 85°C |
| Multimode | Corning 50/125/250 μm | 100/200 KPSI | 85°C |
| Multimode | Corning 62.5/125/250 μm | 100/200 KPSI | 85°C |
| Single Mode (Si/PFA) | 10/125/400/700 μm | 200 KPSI | 200°C |
| Multimode (Si/PFA) | 50/125/250/700 μm | 200 KPSI | 200°C |
Additional details:
- Compatible with all major optical fiber types, including insulated conductors
- Up to 16 solid colors available
- Fiber weight: 0.16 lbs/km per fiber
Filling Compounds
For added protection and stability, we offer multiple gel-filled options designed to withstand high temperatures and long-term field exposure.
| Filling Compound | Temperature Rating |
|---|---|
| LA 444 | 150°C |
| Sepigel H-200 LWT (with hydrogen scavenger) | 150°C |
Standard Tube Sizes
All measurements are in inches.
| Tube OD | Tube ID | Tube Thickness | Max # of Fibers |
|---|---|---|---|
| 0.033 | 0.021 | 0.006 | 1 |
| 0.046 | 0.036 | 0.005 | 3 |
| 0.046 | 0.034 | 0.006 | 3 |
| 0.050 | 0.040 | 0.005 | 3 |
| 0.052 | 0.042 | 0.005 | 4 |
| 0.052 | 0.040 | 0.006 | 4 |
| 0.069 | 0.057 | 0.006 | 7 |
| 0.071 | 0.055 | 0.008 | 8 |
| 0.074 | 0.058 | 0.008 | 8 |
| 0.078 | 0.062 | 0.008 | 8 |
| 0.092 | 0.076 | 0.008 | 12 |
| 0.092 | 0.072 | 0.010 | 12 |
| 0.094 | 0.078 | 0.008 | 12 |
| 0.094 | 0.074 | 0.010 | 12 |
| 0.098 | 0.082 | 0.008 | 12 |
| 0.098 | 0.078 | 0.010 | 12 |
| 0.106 | 0.090 | 0.008 | 15 |
| 0.106 | 0.086 | 0.010 | 15 |
| 0.118 | 0.102 | 0.008 | 18 |
| 0.118 | 0.098 | 0.010 | 18 |
| 0.125 | 0.109 | 0.008 | 24 |
| 0.125 | 0.105 | 0.010 | 24 |
| 0.142 | 0.126 | 0.008 | 48 |
| 0.142 | 0.122 | 0.010 | 48 |
| 0.150 | 0.134 | 0.008 | 48 |
| 0.150 | 0.130 | 0.010 | 48 |
| 0.200 | 0.184 | 0.008 | 72 |
| 0.200 | 0.180 | 0.010 | 72 |
Engineered for Tough Environments
Corrosion Resistance for Subsea and Chemical Exposure
Protect fiber lines in offshore, subsea, and corrosive industrial environments with materials like 316L stainless steel. These alloys maintain structural integrity under pressure, saltwater exposure, and constant vibration.
High-Temperature Performance
When heat is a critical factor, Inconel® 625 and 321 stainless steel deliver the strength and dimensional stability needed for thermal cycling. Titanium offers lightweight performance at roughly half the density of stainless steel, ideal for aerospace and high-performance energy systems.
Precision Manufacturing for Signal Reliability
Even slight variations inside a tube can disrupt optical performance. K-Tube’s tight-tolerance drawing and continuous eddy-current inspection ensure smooth, consistent pathways for uninterrupted signal transmission.
Why Engineers Choose K-Tube for Fiber Optic Systems
Quick Turnaround for Custom Assemblies
Fast production and rapid delivery for urgent project timelines.
Material Science Expertise
Metallurgists and engineers who understand how tubing performs under extreme conditions.
Proven Reliability
Trusted in subsea, downhole, seismic, and industrial environments around the world.
Single-Source Manufacturing
From raw alloy to finished tube — ensuring full traceability, consistency, and quality control.
Application areas include:
Defense, downhole exploration, seismic monitoring, telecommunications, distributed acoustic sensing (DAS), distributed temperature sensing (DTS), and umbilical cables.sensing (DAS), distributed temperature sensing (DTS), and umbilical cables to connect machinery.