An optical transmission system for mobile communication compensates for disadvantages of the star type and the multicipital type systems. The picture of the effluent is first broken down into pixels. Meanwhile, the failure notification messages received from the in-SAN devices are construed to detect and output an influence of the failure upon the access to a real or virtual volume. Variations in intensity over the illuminated area are minimized using light recycling in conjunction with the reflective diffusers and collimating optics.