In this paper, we study the effects of the divergence of a Gaussian beam in coherence multiplexed coding technique. We use this optical system for high density signal parallel arithmetic operations. We illustrate the variation of the measurement coherence length as function of the angular divergence for different wavelength lambda, beam-waist W0, and z1, the distance travelled by the first beam of the interferometer. We show that the divergence of a Gaussian beam introduces an additional crosstalk between light fields