What is the normal range of fiber optic light decay loss? - Walsun For normal fiber broadband, the ideal range of light attenuation is -20dBm to -25dBm. With light attenuation at -27dBm, speeds are limited to a maximum of 100M. Attenuation in fiber optics is the gradual loss of light signal strength as it travels through a fiber cable. Factors causing fiber loss are various, such as intrinsic material absorption, bending, connector loss, etc. Losses in the optical fiber can be categorified. Whenever tests are performed on fiber optic networks, the results are displayed on a power meter, OLTS or OTDR readout in units of “dB. Every fiber link loses some light along the way, and that loss is expressed in dB because the decibel scale makes it easy to add up small losses across long distances. When -28dBm, the maximum speed can only reach 50M.
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