Fiber Loss Calculators

Always use the same units (inches or mm) in each calculation (unless indicated).
Enter your numbers into the light orange cells. To recalculate, press the TAB key, or click in another yellow box, or click the Update button. Other formulas you’d like to see?

  Glass Fused Silica Plastic      
Typical Index of Refraction 1.58 1.46 1.49      
Typical Attenuation (dB/Meter) 0.67 0.01 0.27    
Actual index and attenuation values depend on wavelength and are available from the manufacturer.  
Fiber Internal Transmission Fiber Length (Meters) Attenuation (dB/m) Total Internal Tx (%)    
(Three calculations provided for comparison)    
Internal Transmission is the loss within the fiber itself.  
Surface Reflection Loss at Normal Incidence Index of Refraction Air Index % Loss/ Surface % Tx dB Loss/ Surface %Tx 2 Surfaces    
Reflection losses can be reduced with Anti-Reflection coatings or Index Matching Gel.  
Fiber Bundle External Transmission Packing Fraction (85% Typ) Clad Diameter (um) Core Diameter (um) Clad/Core Area Ratio Reflectivity (Tx2 from above) Total Internal Tx (from above) Total External Tx (%)  
(Three calculations provided for comparing fiber diameters and attenuation)  
External Transmission includes packing, cladding, reflection, and fiber losses. Packing refers to the interstitial areas of the bundle.  
Convert Feet Feet Inches mm Meters  
Convert mm mm Inches Feet Microns  
Convert meters Meters Feet Inches mm