Optical loss is measured in “dB” which is a relative measurement, while absolute optical power is measured in “dBm,” which is dB relative to 1mw optical power Loss is a negative number (like –3. 2 dB) while power measurements can be either positive (greater than the. Optical Signal Attenuation is the single greatest factor limiting the distance and performance of your network. Understanding it is crucial for anyone involved in data centers, telecommunications, or enterprise networking. This guide will demystify signal loss, explore its causes, and show you how. Attenuation is the loss of signal strength of an electrical or networking system while in transmission. Electrical and electronic gadgets involve. Fiber Optic Measurement Units: "dB" and "dBm" Whenever tests are performed on fiber optic networks, the results are displayed on a power meter, OLTS or OTDR readout in units of “dB. Important principles of fiber-optic technology are described below. This loss happens due to a variety of factors. It's measured in decibels per kilometer (dB/km), and it determines how far a signal can travel before it becomes too weak to read.