An optical storage device decreases the influence of return light to the laser light source and prevents an increase of power consumption even if high frequency superimposing is performed. The secure USB storage device also includes a USB secure microcontroller capable of authorizing access to the memory through the memory controller to thereby secure the memory. Therefore, the flux concentration cores are able to be arranged around the bus bars even when the spaces between the bus bars are narrow. The nodes of the first class are configured to transmit each of said segments directly to the nodes of said second class, wherein the first class is not fully interconnected with the second class.