Coherence measurement of a grating-based white-light optical signal processor

Abstract
A two-beam interference technique for coherence measurement in the Fourier plane of a grating-based white-light optical signal processor is presented. The visibility measurement is obtained with a scanning photometer at the output plane of the processor. The degree of coherence as a function of slit separation, due to source size, input object size, and the spatial frequency of the sampling grating, is plotted. The results show that the degree of coherence increases as the spatial frequency of the sampling grating increases. However, this improvement of coherence is somewhat more effective in the direction perpendicular to the light dispersion. Thus, this white-light signal processing technique is more effective in one dimension. Since this white-light processor is capable of processing the signal with the entire spectral band of the light source, it is very suitable for color image processing.