When selecting the best optical fiber power meter for your needs, prioritize accuracy, wavelength range compatibility (e., 850nm, 1310nm, 1550nm), and ease of use. What is a Fiber Optic Power Meter? A fiber optic power meter is a type of testing instrument that measures the level of light power being transmitted through a fiber optic cable. But it doesn't have to be hard. For most field technicians and network installers, a handheld dual-wavelength model with auto-ranging capability and LCD backlighting. Below are general answers on how to choose an optical power meter from the list of Gao Tek's optical power meters.