In a short-distance local area network (LAN), where the endpoints are within walking or talking, technicians can successfully use an economical combination optical multimeter at either end, a stable light source at one end and an optical power meter at the other end. 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. It plays a critical role in testing and diagnosing optical networks, ensuring there are no signal strength problems and determining any difficulties. The term "optical power meter" may sound generic, but in popular usage, it specifically implies a fiber optic power meter.