Patent ID: 6999655

Claim:
An optical communication system for transmitting and receiving optical signals between an optical sender and an optical receiver via an optical transmission path, comprising: a polarization-mode dispersion providing apparatus that includes a first element which gives a variable polarization-mode dispersion to an optical signal transmitted from said optical sender, and drives said first element in accordance with a variable pattern previously determined between said optical sender and said optical receiver, to send the optical signal provided with the variable polarization-mode dispersion to said optical transmission path; and a polarization-mode dispersion restoring apparatus that includes a second element which gives the variable polarization-mode dispersion to the optical signal sent from said optical transmission path to said optical receiver and also has a configuration and a characteristic substantially same as those of said first element, and drives said second element in accordance with said variable pattern, to give the optical signal the polarization-mode dispersion negating the variable polarization-mode dispersion provided by said polarization-mode dispersion providing apparatus, thereby sending the optical signal restored to the state at the transmission time, to said optical receiver.