Patent ID: 6414773
Filing Date: 2002-07-02
Classification: H04B

Abstract:
An optical digital communication apparatus comprising a transmission section for emitting an optical signal corresponding to a digital signal serving as an object of transmission and a reception section for receiving the optical signal and converting the optical signal into a digital signal, characterized in thatthe transmission section including: a light-emitting element for emitting light in response to a digital signal serving as an object of transmission; and optical signal emission means for dividing the optical signal emitted from the light-emitting element in two as two linearly polarized light components which are orthogonal to each other and for emitting the two linearly polarized light components as circularly polarized light components or elliptically polarized light components having the same rotating direction, and the reception section including: first light-receiving means for receiving only circularly polarized light components or elliptically polarized light components having the rotating direction of the circularly polarized light components or the elliptically polarized light components emitted from the optical signal emission means of the transmission section to convert the circularly polarized light components or the elliptically polarized light components into an electric signal; second light-receiving means for receiving only circularly polarized light components or elliptically polarized light components having a rotating direction different from that of the circularly polarized light components or the elliptically polarized light components emitted from the optical signal emission means of the transmission section to convert the circularly polarized light components or the elliptically polarized light components into an electric signal; and subtraction means for receiving the electric signal output from the first light-receiving means and the electric signal output from the second light-receiving means to output a difference between the two electric signal levels.