Product Overview

Sapphire Optical Fiber is a single-crystal optical transmission medium made from high-purity aluminum oxide (Al₂O₃). Unlike conventional silica fibers, sapphire fiber is not an assembly of glass strands but a monolithic single crystal drawn directly from molten sapphire. This structure endows it with exceptional mechanical strength, chemical inertness, and stability in extreme environments where standard fibers fail.

Sapphire fibers maintain excellent optical transmission from the visible to mid-infrared range (0.4–4.5 μm) and operate reliably at temperatures up to 2000°C. They are ideal for harsh industrial, aerospace, and scientific sensing applications, including environments with high temperature, pressure, vibration, or corrosive gases.

Key Features & Advantages

• Extreme Temperature Resistance:
  Withstands continuous operation at up to 1900°C and transient exposure to higher temperatures without degradation.

• Broad Spectral Transmission:
  Excellent light transmission from visible to mid-infrared wavelengths, enabling optical sensing, spectroscopy, and laser power delivery.

• Superior Mechanical Strength:
  Monocrystalline sapphire structure offers outstanding tensile strength and fracture toughness compared to glass fibers.

• Chemical & Radiation Stability:
  Resistant to acids, alkalis, and radiation damage, making it ideal for nuclear, aerospace, and chemical environments.

• Non-Brittle Construction:
  Unlike silica, sapphire fibers are not prone to catastrophic fracture, ensuring stable performance even under vibration or mechanical stress.

Production Principle

Sapphire optical fibers are produced through crystal growth and fiber pulling. A seed crystal is introduced into a high-purity molten alumina environment, and a thin sapphire filament is drawn under precise temperature and pulling rate control. This “Laser-Heated Pedestal Growth (LHPG)” or “Edge-defined Film-fed Growth (EFG)” process yields a single-crystal fiber with minimal defects and precise diameter tolerance.

The resulting sapphire fibers are then polished, annealed, and optionally coated with protective cladding layers (such as metal, ceramic, or polymer coatings) depending on the intended application.

Applications

• High-Temperature Sensing:
  Used in thermometry, pyrometry, and combustion monitoring in engines, turbines, and furnaces.

• Infrared Spectroscopy:
  Suitable for IR signal transmission in analytical instruments and process control systems.

• Laser Power Delivery:
  Capable of transmitting high-power laser energy for cutting, welding, or surface treatment applications.

• Medical and Scientific Research:
  Used in endoscopy and spectroscopy systems where conventional fibers cannot withstand sterilization or heat.

• Aerospace and Defense:
  Provides reliable data transmission and sensing in jet engines, propulsion systems, and radiation zones.

Technical Specifications (Typical Values)

Why Choose Sapphire Fiber

Sapphire optical fibers outperform silica and chalcogenide glass fibers in extreme thermal and chemical environments. They are not only a robust optical conduit but also a durable sensing element for hostile settings. Their ability to operate at high temperatures and transmit infrared light makes them indispensable for industrial process monitoring, aerospace instrumentation, and scientific research.

FAQ

Q1: What makes sapphire optical fiber different from silica fiber?
A: Sapphire fiber is a single-crystal solid fiber, not a bundle of glass fibers. It can withstand temperatures above 1000°C and transmits infrared light beyond the limit of silica (2.2 μm).

Q2: Can sapphire fibers be bent like regular optical fibers?
A: Sapphire fibers are more rigid and require a larger bending radius (typically 50× diameter) to prevent microcracks.

Q3: Is sapphire optical fiber transparent to visible light?
A: Yes, it has high transparency from visible to mid-infrared wavelengths (0.4–4.5 μm).

Q4: Do sapphire fibers require cladding?
A: Bare sapphire fibers are often used, but optional coatings can improve mechanical protection and light confinement for specific uses.