A wavelength conversion device that obtains, from an input light, a wavelength-converted light with a wavelength shift by a wavelength shift amount of \u0394\u03bb is disclosed. A diamond-like carbon electronic device can include a conductive diamond-like carbon cathode having specified carbon, hydrogen and sp2 bonded carbon contents. At an intermediate node in the network between the end nodes, a predetermined segment of the data is maintained in a memory as a buffer.