| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technology of suppressing an optical signal being returned to optical branch couplers of prior arts. <P>SOLUTION: Middle parts of a plurality of optical transmission lines are optically coupled to configure an optical branch coupling section and a plurality of input/output port sections are configured by combining input port sections 22 and output port sections 24 of the optical transmission lines. Each of the input/output port sections is provided with a return signal suppression section 40 that externally outputs a signal resulting from ANDing an inverted logic signal on the basis of an optical signal received from an external node and a logic signal on the basis of an output signal via the optical branch coupling section 14 to the external node from its output port section. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
