Patent ID: 7724995

Claim:
Optical device (D) for transforming the propagation mode of optical signals, comprising at least a first mode converter, ( 3 ) associated with a multimode fibre ( 4 ), the first converter ( 3 ) being supplied with signals that are propagated in accordance with a first guided mode and delivering those signals in the multimode fibre ( 4 ) partly in the first guided mode and partly in a second guided mode of a higher order than the first, characterized in that the multimode fibre ( 4 ) comprises at least first passive filtering means (R, R 1 ) which are arranged to convert the first guided mode into at least one dissipative cladding mode in order to prevent or limit the propagation of the signals in this first guided mode while at the same time authorising the propagation of the signals in the second guided mode in the multimode fibre ( 4 ).