Optical Attenuation
Optical attenuation is the reduction in light-signal level as it travels through a fibre, expressed here in decibels per metre.
It is a loss per unit length rather than the total loss of an assembled cable. Lower attenuation means less signal is lost over the same length under the same measurement conditions.
Optical Attenuation — Optical Cable
For an optical audio cable, attenuation helps describe how much light remains available to the receiver as cable length increases. Connector losses and the sending and receiving devices also affect whether the complete link works reliably.
Compare values at the same wavelength and with matching units; a per-metre figure cannot be compared directly with a whole-cable loss figure. Attenuation alone does not specify the maximum usable length or an audio-quality improvement. Keep the cable’s stated operating length and compatibility separate from this measurement of the fibre.