The invention concerns a method for monitoring an optical waveguide between
a monitoring terminal point and a monitoring unit, in which an optical
data signal from a transmitter, and for amplification, pump light from a
pump laser, is emitted into the optical waveguide, wherein a monitoring
signal transmitted by the monitoring unit is returned via the same
waveguide to the monitoring unit by a reflection device located at the
monitoring terminal point, in particular a Bragg grating placed in the
optical waveguide, and wherein the reflection device is tuned to a
reflection that is exactly the wavelength of the monitoring signal, as
well as a monitoring system and a monitoring unit for said Method.
