Measured null depth of the transmissive chessboard phase mask in different broadband filters (colored segments of line), which include the large band of 470–830 nm. The black line is the theoretical performance of a perfect component and the green line is the simulated null depth of the real device when the minimum of the fringe pattern is used. The blue line which is the same quantity when using just the central pixel value as the measure, assumes that the fiber will be placed there and not moved (as it would likely be in the case of a space experiment). The dotted line gives the nulling depth for a perfect Bracewell interferometer.