FIELD: fault detection and location. SUBSTANCE: in agreement with method optical fiber is bent with small radius, sequence of probing optical pulses is injected into sheath of fiber through its side surface in point of bend, optical signal propagating in fiber towards its nearest end is received at mentioned end, characteristic of backward scattering of optical fiber is recorded and used to determine distance to point of fault in sheath of optical fiber. Device for implementation of method includes pulse generator, source of optical radiation, directional optical coupler, optical radiation detector, scaling unit, display unit, unit to input/output optical radiation into/from optical fiber through bend whose input is connected to output of directional optical coupler and whose output is linked to side surface of tested optical fiber in point of bend. EFFECT: improved test of condition of sheath of optical fiber. 2 cl, 1 dwg
