| 摘要 |
PURPOSE:To attain duplex communication only by providing one optical fiber line to each subscriber by applying wavelength-division multiplex transmission technology. CONSTITUTION:Signals of wavelengths lambdaD1-lambdaD3 from exchange station 1 are tranmitted through optical fiber 30 to line concentrator 7, where they are separated by an interference-film filter, etc., and separated signals are separately transmitted through optical fiber lines 31-33 corresponding to subscribers 21-23 and then inputted to photo receiver 5 by way of corresponding photo separating couplers 6. Signals of wavelengths lambdaU1-lambdaU3 from subscriber sides, on the other hand, reach line concentrator 7 via optical fiber lines 31-33 by way of the route opposite to signals from exchange station 1 and all signals are transmitted from line concentrator 7 to exchange station 1 via one optical fiber 30. In this way, only providing one optical fiber to each subsciber makes duplex communication possible and required optical fiber lines can be reduced most in number. |
