Patent ID: 8644707

Claim:
A bidirectional optical amplifier arrangement arranged between a first network termination and a second network termination and passed through in one direction by an optical downstream signal and in an opposite direction by an optical upstream signal, comprising: a first branching and combination unit arranged at the first network termination end, wherein the first branching and combination unit has at least one common connection for both signals at the first network termination end, and an output for the downstream signal and an input for the upstream signal at the second network termination end, the output for the downstream signal is connected via a unidirectional optical amplifier to an input for the downstream signal from a second branching and combination unit; an output for the upstream signal from the second branching and combination unit is connected via a transponder to the input for the upstream signal of the first branching and combination unit, the second branching and combination unit has a common connection for both signals at the second network termination end, which connection is connected to a bidirectional optical amplifier, from which a common connections for both signals leads to the second network termination; a power monitoring device for controlling a gain of the unidirectional optical amplifier; a power monitoring device for controlling a gain of the bidirectional optical amplifier; the optical amplifiers are controlled such that, in the downstream direction, the unidirectional optical amplifier has a low noise factor, and the bidirectional optical amplifier has a constant and high output power; and the output power of the unidirectional optical amplifier is set such that the gain of the bidirectional optical amplifier is sufficiently low in order neither to satisfy an oscillation condition for the bidirectional optical amplifier nor to cause noticeable signal distortion and that the input power of the bidirectional optical amplifier is considerably greater in the downstream direction than in the upstream direction.