| 摘要 |
PURPOSE:To enable information transmission by exciting light in addition to information transmission by signal light by modulating the exciting light with a modulating signal whose frequency is high enough to have a shorter period when the fluorescent light life in an excitation state. CONSTITUTION:The exciting light 6 is modulated with the modulating signal whose frequency is high enough to have the shorter period than the fluorescent light life in the excitation state. Namely, when the signal light and exciting light are propagated in a rare earth doped fiber in the same direction, the exciting light is used as a carrier to transmit the monitor signal of an optical repeater. When the signal light and exciting light are propagated in the rare earth doped fiber in mutually reverse directions, on the other hand, duplex transmission, i.e. the information transmission by the signal light and the information transmission using the exciting light as the carrier become possible. Thus, the information transmission by the exciting light becomes possible in addition to the information transmission by the signal light. |
