Patent ID: 6985654

Claim:
An optical device (D) for transforming the propagation mode of optical signals, the device comprising mode transformation means ( 3 – 5 ) associated with a multimode fiber ( 2 ), in which said mode transformation means ( 3 – 5 ) comprise first and second mode converters ( 3 and 5 ) coupled to each other by a multimode fiber portion ( 4 ) of selected length (L), said first converter ( 3 ) being fed with signals propagating in a first mode and delivering said signals to said fiber portion ( 4 ) in part in said first mode and in part in a second mode of order higher than the first, and said second converter ( 5 ) being arranged to cause the signals in said first and second modes to interfere so that, on outlet therefrom, they present a selected spectral spacing (Δλ).