| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of level difference in a light-receiving level on the side of a master station for receiving an optical signal synthesized by an up optical branching filter inside a slave station group. SOLUTION: This device has a master station 10, plural slave station groups 20A (20B) respectively having plural slave stations 20, a down optical transmission line 30 connected via plural down optical branchers 21a-21e to slave stations by multidrop topology, so as to transmit the optical signals from the master station 10 to the slave stations 20, and plural up optical transmission lines 40 connected via up optical branching filters 26a, 26b, 26d and 26e to slave stations inside respective slave station groups by the multidrop topology for each slave station group, so as to transmit optical signals from the slave stations in the respective groups to the master station 10. In this case, light-emitting elements mutually separating light-emitting wavelengths at prescribed intervals are respectively arranged at the respective slave stations, so as to minimize the level difference of optical signal reception from each slave station to the master station 10, after synthesis at the optical branching filters 26a and 26b (or 26d and 26e), while considering the transmission loss of the up optical transmission line 40 and the wavelength characteristics of optical branching ratios at the up optical branching filters. |
