A identification system comprising at least one non-volatile memory device containing identification data, a communication bus for the memory device that is independent of any other system bus, and a controller to manage the integrity of the identification data. Preferably, the treated particulate is calcined a second time under the same conditions as the first before final activation with a hydrogen-containing gas. This configuration effectively improves the deterioration in crosstalk between adjacent signal channels on a par with the case where the slab and channel waveguides are directly connected to each other.