In recent years, new coronagraphic schemes have been proposed, the mostpromising being the optical vortex phase mask coronagraphs. In our work, a newscheme of broadband optical scalar vortex coronagraph is proposed andcharacterized experimentally in the laboratory. Our setup employs a pair ofcomputer generated phase gratings (one of them containing a singularity) tocontrol the chromatic dispersion of phase plates and achieves a constantpeak-to-peak attenuation below 1:1000 over a bandwidth of 120 nm centered at700 nm. An inner working angle of $\lambda$/D is demonstrated along with a rawcontrast of 11.5\,magnitudes at 2$\lambda$/D. A more compact setup achieves apeak-to-peak attenuation below 1:1000 over a bandwidth of 60 nm with the otherresults remaining the same.
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