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 reference) or negative (less than. Therefore, dB is expressed as: where V1 and V2 are the amplitudes to be compared. Optical fiber is a medium to carry information. It is made of silica-based glass. The. In communication engineering, the magnitude of power is usually expressed as a dBm value, which is a logarithmic measure and is defined as decibels relative to 1mW power level, that is, dBm represents decibels per milliwatt. It's a dimensionless unit that actually specifies the power ratio rather. This document serves as a quick reference tool for understanding optical technologies, focusing specifically on decibels (dB), dBm, attenuation, and measurements related to optical fibers. Watts or dBm), whereas the transmission path degradation is a relative value (e.
[PDF Version]