What Causes Signal Loss in Fiber Optic Cables?
Signal loss—also known as attenuation—is one of the key factors that affects the performance of fiber optic networks. Understanding its causes helps ensure better installation, maintenance, and long-term network reliability.
Here are the main reasons why signal loss occurs:
1. Fiber Bending
• Macro-bending: Large, visible bends that cause light to escape from the fiber core. This often happens if the cable is pulled around sharp corners or coiled too tightly in a splice tray.
• Micro-bending: Tiny, microscopic bends or pressure points caused during cable manufacturing, storage, or by external pressure (like a cable tie that is too tight).
Both types of bending change the angle of light reflection, causing it to "leak" into the cladding and reduce signal strength.
2. Poor Connector or Splice Quality
• Dust, oil (even from a fingerprint), scratches, and physical misalignment at connectors or splices cause insertion loss.
• Reflectance: If connectors aren't perfectly mated, light can bounce back toward the source, causing errors.
3. Impurities & Scattering
• Rayleigh Scattering: Even the best glass has microscopic density variations. These imperfections act like tiny mirrors, scattering light in different directions. This is the primary cause of signal loss over very long distances.
4. Absorption
• Materials inside the fiber (residual water vapor or trace metals) absorb light energy and turn it into heat.
• Water Peaks: Specific wavelengths (like 1383nm) are particularly susceptible to absorption by hydroxyl (OH) ions.
5. Wavelength Selection
• Different wavelengths experience different levels of attenuation.
• 850nm: Used for short-distance (Multimode).
• 1310nm & 1550nm: Used for long-distance (Singlemode) because they offer the lowest loss.
6. Environmental & Installation Factors
- Extreme temperature, improper pulling force,tight cable ties, or crushing during installation can increase signal loss over time.
How to Reduce Attenuation?
• Clean and Inspect: Always use a microscope to check connectors and clean them with lint-free wipes and 99% isopropyl alcohol.
• Respect Bend Radius: Follow the manufacturer's specified minimum bend radius during installation.
• High-Quality Splicing: Use a fusion splicer for permanent connections to minimize loss.
• Proper Wavelength: Match your equipment to the fiber type and optimized wavelength.
If you found this helpful feel free to ask more about the optical fiber cable ,follow our sites https://dtechtrading.com.np/post for more fiber optics insights .