| 摘要 |
PURPOSE: To provide an optical branching and inserting system which is decreased in the beats generated between light signals leaking to an output port by crosstalks. CONSTITUTION: The light signal 12 subjected to wavelength multiplexing is branched to the light signals 131 to 13N of each of respective wavelengths by a branched light inserting filter 11. Among these signals, the light signals 132 to 13N are rotated in their polarization direction by 90 deg. by a Faraday rotator 18. The light signal 22 of the same wavelength as the wavelength of the light signal 131 is inputted to a polarized light controller 23 from an optical transmitter 19 for insertion for changing the polarization direction. The light signal 131 and the output light of this polarized light controller 23 are interfered by a coupler 29, by which the polarization angle of the polarized light controller 23 is so changed as to minimize the interference quantity. Two pieces of output light of the polarized light controller 23 and the Faraday rotators 18 are subjected to wavelength multiplexing by the branched light inserting filter 11 and is outputted from the output port 14. The light leaking to the output port by the crosstalks and its polarization direction are changed in such a manner and, therefore, the beats are decreased. |
