These meters provide a precise and reliable method for quantifying the power level of light across various wavelengths, making them essential instruments in the testing and calibration of optical systems. An optical power meter consists of a sensor, a detector, and a display unit. It details the main components, including sensor heads and display units, and explains the two primary sensor technologies: robust thermal sensors for high powers and. An optical power meter (OPM) measures the power levels of light signals in devices that transmit data or power using light. The term "optical power meter" may sound generic, but in popular usage, it specifically implies a fiber optic power meter.