| 摘要 |
The present invention provides a free-space optical WDM communication system that couples received channels into an optical fiber to use optical amplifiers at the receiver and thereby to increase the transmission distance. The transmitted and received channels are coupled into a free space and a fiber, respectively, using the same light beam emitting and focusing (LBEF) unit that consists of focusing optical assemblies, beam-to-fiber couplers, and a fiber coupler. The LBEF unit is connected to both transmitter and receiver circuits using an optical circulator or a WDM coupler. The invention includes the use of an amplified spontaneous emission and also provides a free-space optical repeater that amplifies or regenerates free-space WDM channels with an add-drop multiplexing capability during the propagation. |
