650/700°C SST Fiber Optic Cable - Gold-Coated Fiber In Metal Tube (FIMT) - Communication / Sensing Optical Cable

Aliases: 650/700°C Gold-Coated Metal Armored Fiber, 650/700°C All-Metal Structured Sensing Cable, 650/700°C Alloy 825 Gold-Fiber Unit, 650/700°C Ultra-High Temp Hermetic Fiber Probe, 650/700°C Polymer-Free High-Temp Fiber Cable, 650/700°C Zero-Outgassing Optical Cable, 650/700°C Aero-Engine Thermal Sensing Fiber, 650/700°C Deep Geothermal Metal Armored Cable, 650/700°C Molten Metal Environment Fiber Sensor

1. Product Overview of OFSCN® 650/700°C Ultra-High Temperature Fiber Optic Cable

The OFSCN® 650/700°C Ultra-High Temperature Fiber Optic Cable stands as one of the highest-rated specialty cables in the fiber optic sensing industry. It features a single-layer seamless metal tube encapsulation (standard Alloy 825) housing OFSCN® Gold-coated Optical Fibers. By utilizing a metal coating instead of polymers, this cable eliminates issues like evaporation, outgassing, or carbonization at extreme temperatures. With Alloy 825 as the standard jacket, it offers exceptional resistance to stress corrosion cracking and oxidation, making it the premier choice for distributed sensing in metallurgy, aerospace, and ultra-deep geothermal wells.

2. Technical Parameters of OFSCN® 650/700°C Ultra-High Temperature Fiber Optic Cable

Key Parameters	Spec A (2.0mm)	Spec B (3.0mm)	Custom Options
Outer Diameter (OD)	2.0 mm	3.0 mm	1/8" (3.175mm) / 1/16" (1.58mm)
Wall Thickness	0.2 mm	0.3 mm	Tailored to requirements
Tube Material	Alloy 825 (Default) / 316L	Alloy 825 (Default) / 316L	825 / 316L / Hastelloy
Theoretical Weight (825)	~9.21 kg/km	~20.72 kg/km
Tensile Strength	> 550 N	> 1200 N	Superior high-temp creep strength
Crush Resistance	> 100 MPa	> 100 MPa	Rated for high-pressure reactors
Operating Temp (SM)	-269 ~ +700°C	-269 ~ +700°C	Using Gold-coated SM Fiber
Operating Temp (MM)	-269 ~ +650°C	-269 ~ +650°C	Using Gold-coated MM Fiber
Min. Order Qty (MOQ)	100 Meters	100 Meters	Stock or custom production

3. Internal Fiber Configuration of OFSCN® 650/700°C Ultra-High Temperature Fiber Optic Cable

Equipped with high-reliability Gold-coated fibers where the metal layer is hermetically bonded to the glass:

• Fiber Types: * Single-mode (SM): OFSCN® Gold-coated SM Fiber (Rated 700°C)
  • Multi-mode (MM): OFSCN® Gold-coated MM Fiber (Rated 650°C)
• Coating Material: High-purity Gold (Au), providing excellent chemical stability and thermal conductivity.
• Connectivity: Specialized metal-fiber high-temperature termination or fusion splicing is recommended.

4. DFOS Compatibility Analysis (Ultra-High Temp Optimized) of OFSCN® 650/700°C Ultra-High Temperature Fiber Optic Cable

4.1 Distributed Temperature Sensing (DTS) — Raman Scattering

• Extreme Endurance: Gold-coated multi-mode fiber does not peel or discolor at 650°C, ensuring long-term stability of Raman backscatter signals.
• Dual Hydrogen Barrier: The combination of Alloy 825 and the gold coating provides a "double shield" against hydrogen ingress, vital for maintaining low attenuation in ultra-deep oil and gas wells.

4.2 Distributed Temp. & Strain Sensing (DTSS) — Brillouin Scattering

• High-Temp Structural Monitoring: The 700°C SM sensing unit can be deployed in aircraft turbine sections or high-pressure steam pipes.
• Mechanical Protection: Alloy 825 maintains high rigidity at elevated temperatures, accurately transmitting structural strain while protecting the fiber from micro-bending under 100 MPa pressure.

4.3 Distributed Acoustic/Vibration Sensing (DAS/DVS) — Rayleigh Scattering

• High-Fidelity Transmission: Gold is a "hard" coating with a mechanical modulus far exceeding polymers. At 650/700°C, vibrations are transmitted through the Alloy 825 tube and gold layer to the fiber core with zero loss of coupling.
• Acoustic Stability: Solves the problem of acoustic coupling loss caused by polymer coating failure above 300°C.

5. Sensing Technology Matching Matrix of OFSCN® 650/700°C Ultra-High Temperature Fiber Optic Cable

Sensing Tech	Principle	Recommended Fiber	Key Advantages
DTS	Raman Scattering	Gold-coated MM (650°C)	Ultra-high temp & dual hydrogen shield; Ideal for smelting furnaces.
DAS / DVS	Rayleigh Scattering	Gold-coated SM (700°C)	All-metal structure & superior acoustic coupling; Ideal for turbine monitoring.
BOTDA / R	Brillouin Scattering	Gold-coated SM (700°C)	High thermal stability & crush resistance; Ideal for high-pressure vessels.
F-P / FBG	Wavelength Shift	Gold-coated SM (700°C)	Supports high-temp grating writing; Alloy 825 provides top-tier corrosion protection.