A network element (10) comprises: a first optical input section (1), a first optical output section (2), a second optical input section (3) and a second optical output section (4) a first and second insertion and extraction modules (30, 40), each of said insertion and extraction modules comprising a wavelength selection switch (31, 41), a first optical coupler (8) comprising two bidirectional branches (21, 22) respectively connected to the first selectable port of the first and second insertion and extraction modules, and a second optical coupler (11) comprising two bidirectional branches (23, 24) respectively connected to the second selectable port of the first and second insertion and extraction modules.