This white paper describes some of the important factors affecting testing and outlines the design specifications that these next-generation OPMs must include in order to ensure that reliable testing and certification of optical fiber networks can be completed by any technician. This white paper describes some of the important factors affecting testing and outlines the design specifications that these next-generation OPMs must include in order to ensure that reliable testing and certification of optical fiber networks can be completed by any technician. We describe NIST measurement services for the calibration of optical fiber power meters. To augment the absolute power measurements NIST provides nonlinearity, spectral responsivity, and uniformity measurements. We explain the measurement standards, systems, methods, and uncertainties related to. Keysight optical power meters measure optical signal strength, providing multi-channel measurement processing and system control while offering rapid response times, wide dynamic range, and simple integration into automated test setups. Our optical power meters feature built-in calibration factors. When combined with a light source, the instrument is called an Optical Loss Test Set, or OLTS, and is typically used to measure optical power and end-to-end optical loss. They are designed to measure the power of optical signals, which is essential for ensuring the proper functioning of optical systems.