Optics In an optical link, if a known amount of optical power, in dBm (referenced to 1 mW), is launched into a fiber, and the losses, in dB (decibels), of each component (e.g., connectors, splices, and lengths of fiber) are known, the overall link loss may be quickly calculated by addition and subtraction of decibel quantities.
Optics in AN opTiCal lInk, iF A KnOwn amouNt of oPTicAL poWeR, in dBm (ReFerenCEd to 1 mw), is lAunchED IntO A fIber, aNd thE lOssEs, iN Db (decibELs), oF eACH comPonent (e.g., ConneCtOrS, splices, aND lengths of fIber) are knoWn, The OveRall Link loss MAY bE qUIcklY CAlcuLatED By addition ANd subTraction Of deCIbel quAnTitiES.