Patent ID: 8805200

Claim:
An optical transmission system comprising: an optical transmitter configured to transmit an optical signal, where an X-polarized signal and a Y-polarized signal each having a predetermined frame structure are polarization-multiplexed, to an optical transmission path; and an optical receiver configured to receive the optical signal that has propagated through the optical transmission path, the optical transmitter including: a delay generator configured to delay a frame start position of the Y-polarized signal, by a predetermined delay time, relative to that of the X-polarized signal, and the optical receiver including: a polarization splitter configured to split the received optical signal into two polarization signals which are orthogonal to each other; a time difference detector configured to detect a time difference of frame start positions between the two polarized signals; and a polarization identifying unit configured to identify which of the two polarized signals is the X-polarized signal or Y-polarized signal, wherein a frame period of the X-polarized signal is equal to that of the Y-polarized signal, and the delay time is less than a half of the frame period.