| 摘要 |
PURPOSE: To provide an information read-out device capable of reading out information without almost inflicting a loss on a transmitting pulse modulation signal. CONSTITUTION: A light amplifier 4 is provided in the route of an optical fiber 3 transmitting a pulse modulation signal beam, and a non-linear medium 6 to which a third non-linear effect is imparted is provided on the outgoing end side of the light amplifier 4, and the non-linear medium 6 absorbs light having the intensity less than a threshold level among the pulse modulation signal beams entering from the optical fiber 3 side, transmits the light having the intensity being the threshold level or above and the refractive index of the non-linear medium 6 changes when the light having the intensity being the threshold level or above transmits. Further, a DFB laser 9 by which laser light is made incident on the non-linear medium 6 so as to be intersected with the pulse modulation signal beam transmitting through the non-linear medium 6 is provided, and an avalanche photodiode(APD) 8 receiving the laser light transmitting through the non-linear medium 6 is provided, and the change of the refractive index of the non-linear medium 6 by the pulse modulation signal beam is read out by the APD 8 to read out the signal information of the pulse modulation signal beam. |
