  In order to meet the theoretically achievable imaging performance,
calibration of modern radio interferometers is a mandatory challenge,
especially at low frequencies. In this perspective, we propose a novel parallel
iterative multi-wavelength calibration algorithm. The proposed algorithm
estimates the apparent directions of the calibration sources, the directional
and undirectional complex gains of the array elements and their noise powers,
with a reasonable computational complexity. Furthermore, the algorithm takes
into account the specific variation of the aforementioned parameter values
across wavelength. Realistic numerical simulations reveal that the proposed
scheme outperforms the mono-wavelength calibration scheme and approaches the
derived constrained Cram\'er-Rao bound even with the presence of
non-calibration sources at unknown directions, in a computationally efficient
manner.
