Fiber-optic tap for monitoring light intensity in a fiber-optic cable (1) constr ucted by removing the buffer layer (4) and rough polishing the cladding layer (3) bene ath so that light in the cladding layer (3) is emitted therefrom. A photodetector (13) is lo cated 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 t he fiber. The signal produced by the photodetector (13) can trigger an alarm and can also be f ed back to the light source to maintain the light intensity in the fiber (1). An array o f photodetectors (13) can be provided in a unit to monitor multiple fibers (1).
