Undulators are the most advanced sources for the gen-eration of synchrotron radiation. The photons generated by a single electron add up coherently along the electron trajectory. In order to do so the oscillatory motion of the electron has to be in phase with the emitted photons along the whole undulator. Small magnetic errors can cause un-wanted destructive interferences. In standard permanent magnet undulators the magnetic errors are reduced by ap-plying shimming techniques. Superconductive undulators have higher magnetic fields than permanent magnet undu-lators but shimming is more complex. In this paper it is shown that coupled superconductive loops installed along the surface of the superconductive undulator coil can sig-nificantly reduce the destructive effect of the field errors. This new idea might allow the building of undulators with a superior field quality.