Power meter measurement in five steps: 1) Clean the meter port and the patch cord. 5) Read the value, and compare against the. Working with fiber optic cables requires precise measurements to ensure proper signal transmission. Select the correct wavelength and set your reference. You measure optical power in dBm or insertion loss in dB. Consistent procedures ensure accuracy. The meter works by converting the received optical signal into an electrical signal using a. This guide walks through the full procedure -- from cleaning the connector to interpreting the result -- so your measurements are trustworthy on the first try.