A device for transmitting optical signals comprises two collimator units, supported to be rotatable relative to each other about a rotation axis and one derotating optical element. A first beam splitter receives input signals and splits them into at least two signals, so that they are transferred by at least two optical channels over the collimator units and the derotating optical element. After passing the second collimator unit, the signals are combined by a second beam splitter to a single signal, resulting in largely reduced variations of attenuation during rotation.