Dynamic Range 1-1000 nW; 780-1650 nm; Integration Time 1 ms-1 min; USB Interface; Internal Light Source 1. 55 µm Fibotec Fiberoptics' dBM-00-C3rd-FCP dB-Meter measures power stability and power changes across a wide dynamic range with high accuracy and high speed. Optical power meters for fiber optic networks: For the installation, maintenance, and testing of single-mode and multi-mode networks and cables. An OPM uses a photodiode to generate an electrical current proportional to optical power. For SFP testing, the OPM is especially valuable because it helps verify the actual signal leaving a. An optical power meter is an essential fiber optic test tool, used for measuring absolute transmit / receive power in dBm, cable loss in dB, and for continuity checking / troubleshooting.