| 摘要 |
For military and civil secure communications each remote station 12-21 does not itself generate a light beam but instead merely reflects, suitably modified, a light beam transmitted to it by the home station 1-8. The home station codes a laser beam 9, 10, 1 which after beam expansion 2 is transmitted. The remote station detects reception at 17 and initiates modulation at 20 of that part of the received beam which passes through a beam splitter 14 to be reflected at 16 back to the transmitter. The modulation carries the desired secure information from the remote station. <IMAGE> |
