Abstract: An optical communication apparatus in which bidirectional communication may be made over a sole optical fiber. A light emitting device (132) radiates light through an optical system (133) to an optical fiber (76). The light transmitted from the optical fiber (76) is received over optical system (133) by a light receiving device (136). In the optical system (133), such a relationship S?2QN?M>S/2Q?N is set, where M is the light volume of the stray light emitted, Q is the value of a Q-value representing the communication quality as required, S is the light volume of a received signal from a communication partner and N is the sum total of the Gaussian noise.

Abstract: An optical communication apparatus in which bidirectional communication may be made over a sole optical fiber. A light emitting device (132) radiates light through an optical system (133) to an optical fiber (76). The light transmitted from the optical fiber (76) is received over optical system (133) by a light receiving device (136). In the optical system (133), such a relationship S−2QN≧M>S/2Q−N is set, where M is the light volume of the stray light emitted, Q is the value of a Q-value representing the communication quality as required, S is the light volume of a received signal from a communication partner and N is the sum total of the Gaussian noise.

Abstract: The invention provides an optical communication apparatus to communicate a data signal. The optical communication apparatus is capable of firmly carrying out optical communication using an optical transmission media. The optical transmission media may be connected between a first optical communication apparatus and a second optical communication apparatus. Upon a detector detecting an incoincidence between an electric signal outputted from a light receiving element and a test signal, a controller may control a parameter of a light emitting power control signal to increase an intensity of an optical signal outputted from a light emitting element. Upon the detector detecting a coincidence therebetween, the controller may set a current value of a parameter of the light emitting power control signal as a parameter upon a selector selecting the data signal.