One example of a so-called optical interconnection structure for connecting semiconductor chips, primarily high-speed LSI circuits, with an optical signal is shown in FIGS. 1A and 1B. In this structure, LSI circuits 2 on substrate 1 are connected to each other by thin optical waveguide 5 parallel to substrate 1 through PD (PhotoDiode: light-detecting device) 3 and VCSEL (Vertical Cavity Surface-Emitting Laser) 4. In the example shown in FIGS. 1A and 1B, interposers 1a are provided. The number of general connections (parallelism) is in the range from about 100 to 1000. An optical circuit generally refers to an optical fiber, an optical waveguide, and a combination of an optical fiber and an optical waveguide.