  The direct detection and imaging of exoplanets requires the use of
high-contrast adaptive optics (AO). In these systems quasi-static aberrations
need to be highly corrected and calibrated. In order to achieve this, the
pupil-modulated point-diffraction interferometer (m-PDI), was presented in an
earlier paper. This present paper focuses on m-PDI concept validation through
three experiments. First, the instrument's accuracy and dynamic range are
characterised by measuring the spatial transfer function at all spatial
frequencies and at different amplitudes. Then, using visible monochromatic
light, an adaptive optics control loop is closed on the system's systematic
bias to test for precision and completeness. In a central section of the pupil
with 72% of the total radius the residual error is 7.7nm-rms. Finally, the
control loop is run using polychromatic light with a spectral FWHM of 77nm
around the R-band. The control loop shows no drop in performance with respect
to the monochromatic case, reaching a final Strehl ratio larger than 0.7.
