Tap monitors are directional devices that allow the optical power in a fiber to be monitored. A very small proportion of the light is redirected onto a photodiode. This portion of light is so small, with such little other disturbance to the optical path, that the insertion loss of the device can be lower than 0.1 dB. Applications include network monitoring and component optimization.
Tap monitors are available as a component to splice into the system or as a power meter with integrated display that is a calibrated for different wavelength bands. All versions are available in both single mode and PM fibers.