TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Assembly: The mount assembly includes a circuit board. The photoelectric conversion devices and the spherical semiconductor device(s) are mounted on a surface of the circuit board and electrically connected through a wire of the circuit board. The devices are electrically connected by contacting with each other through an electrical-connection portion (14). The mount assembly comprises n spherical photoelectric conversion devices as the photoelectric conversion device (where n is greater than or equal to2, preferably 2 or greater than or equal to3), and x spherical semiconductor devices as the spherical semiconductor device (where x is greater than or equal to1, preferably 1). It has a spherical photoelectric conversion devices that convert a light signal to an electrical signal (where a is greater than or equal to1 and is less than n), and n-a spherical photoelectric conversion devices converting an electrical signal to a light signal. The spherical photoelectric conversion devices and the spherical semiconductor device(s) are arranged in a line and the two spherical photoelectric conversion devices are disposed at both ends of the line. An incident light signal in one direction is divided into greater than or equal to2 directions. The spherical photoelectric conversion device(s) converts a light signal to an electrical signal and receives light signals emitted from optical transmission lines. The spherical semiconductor device(s) electrically connected to the spherical photoelectric conversion device forms an electronic circuit for amplifying a received light signal at an amplification factor depending on a wavelength of the received light signal. The mount assembly includes a passive component. It connects the optical transmission lines and transmits a light signal corresponding to a light emitted from the optical transmission line to the other optical transmission line(s). The optical transmission line has a branch portion in which the mount assembly is disposed.    TECHNOLOGY FOCUS - POLYMERS - Preferred Material: A part or the entire mount assembly is covered with a transparent resin (16) (preferably acrylic resin, polycarbonate resin, polystyrene resin, styrene-acrylonitrile copolymer, or epoxy resin.