Patent ID: 7113662
Filing Date: 2006-09-26
Classification: H04J

Abstract:
1. An add-drop node for wavelength division multiplexing an optical signal transmission on an optical fiber network between multiple add-drop nodes, said node comprising a drop filter ( 78 , 84 , 85 , 88 ), an add filter ( 65 , 84 , 86 , 89 ), a signal channel receiver ( 72 , 93 ), and a signal channel transmitter ( 71 , 92 ) each being connected to a switch ( 68 ) for signal channel relaying between said optical fiber network, and signal channel dropping and adding from and to said optical fiber network, characterized in providing low loss for relayed signals by allowing said drop filter having a low crosstalk isolation, and providing high crosstalk isolation for dropped signal channels by connecting said signal channel receiver to the switch through an additional filter (