What is the attenuation curve and how do I use it?

Attenuation is a decrease of light intensity within a fiber, usually due to absorption and scattering losses. This loss of power is measured in decibels (dB) where

dB = 10*log (P_in/P_out)

where:

P_in, P_out are the input and output powers.

The affects of these losses increase with fiber length. The value dB/m measures power lost in dB for every meter of fiber. Edmund Optics' attenuation curves measure the power loss in dB/m for our Communications Grade Optical Fibers and dB/km for our Optical Grade Fibers across the visible spectrum. For example, our 1000 micron diameter Communications Grade Optical Fiber has an attenuation of approximately 0.1dB/m at 600nm. If you were to use a 2-meter fiber, then the total loss would be 0.2 decibels. If we had an input power of 100mW, the output power would then be 95.5mW, resulting in a 5.5% loss. Resultant output power of a fiber, given its attenuation, can be calculated using the equation below:

P_out = P_in * 10^-dB/10