Vorrichtung und Verfahren zur Überwachung der Lichtintensität in Lichtleiterfasern

Fiber-optic tap for monitoring fight intensity in a fiber-optic cable (1) constructed by removing the buffer layer (4) and rough polishing the cladding layer (3) beneath so that light in the cladding layer (3) is emitted therefrom. A photodetector (13) is located in proximity with the polished surface (12) and optically isolated from other light sources. The signal produced by the photodetector (13) indicates the light intensity in the fiber. The signal produced by the photodetector (13) can trigger an alarm and can also be fed back to the light source to maintain the light intensity in the fiber (1). An array of photodetectors (13) can be provided in a unit to monitor multiple fibers (1).