One embodiment of the present invention provides a system that facilitates automatically generating a performance table for an object, wherein the object is subject to fluid flow. An optical communication system includes at least one pair of optical communication units that each has a bi-directional network interface in which physical bit rates of transmission signals and reception signals are identical, an optical transmitter, and an optical receiver, and that performs bi-directional transmissions via at least one optical fiber. 0 or lower for signal transmission at frequency of 1 GHz, the core layer has thermal expansion coefficient at or below Tg set lower than thermal expansion coefficients of the interlayer layers at or below Tg, the coefficient of the core layer at or below Tg is set to be 75 ppm\xb0 C.