| 摘要 |
PURPOSE: To change the polarized state of a main optical signal with a clock synchronized with the main signal, to extract the clock from the polarized component of the optical signal received through an optical fiber without being affected by polarization fluctuation and to reproduce the main signal synchronized with this clock. CONSTITUTION: An electrooptic transducer 22 receives the main signal of an electric signal and converts it into the main optical signal whose light intensity is modulated, and a polarization scrambler 25 periodically changes the polarized state of the main optical signal an outputs it to an optical fiber 3. Next, a branching filter 41 branches the optical signal transmitted through the optical fiber 3 and a first photodetector 42 converts the first optical signal, which is branched by the branching filter, into an electric signal. Besides, a polarized state detector 50 converts the change of the polarized state into an electric signal corresponding to the second optical signal branched by the branching filter and a clock extraction circuit 55 extracts the polarization scramble frequency from the output of a second photodetector 54. Then, a receiver 43 reproduces the main signal based on the output of the first photodetector 42 and the clock extracted by the clock extraction circuit 55. |
