| 摘要 |
PURPOSE: To realize the optical heterodyne reception of a straight line polarization received signal over a long distance by changing polarization by a half wavelength plate with a fixed polarizing direction coinciding with the straight line polarizing signal component of a received signal. CONSTITUTION: An electronic intermediate frequency circuit 900 and an optical mixing circuit 800 are arranged and a signal mixer 110 is connected with the input terminal 90 of the received signal 1 and the local oscillator 100 of a circularly polarized light local oscillator signal 2. Then an optical device 120 is disposed in mixed signal routes 212 and 221 connecting optically mixed signals 11 and 12 formed in the signal mixer 110 to a polarization mixer 130. Then polarization is changed in the optical device 120 by the half wave length place with a fixed polarizing direction coinciding with the straight line polarizing signal components of the received signal existing in the optically mixed signal 12. Thereby reception is possible though heterodyne transmission is extended over a long distance. |
