| 摘要 |
PURPOSE:To constitute a tree form communication network by making a light transmission wavelength lambdaR of a coupled output of a repeater different from a light transmission wavelength lambdaT of a terminal device so as to make a wavelength receivable at the terminal device and inserting a filter for wavelengths except the wavelength lambdaR to a photodetector of a branch input of the repeater. CONSTITUTION:Optical star couplers are coupled in tree form, and the relaying from the branch side to the feeder side is attained always by a repeater 1 for star coupler. This repeater 1 is assembled in a repeater 21 for light star coupler having output terminals 11, 23 to an input optical fiber of the optical star coupler and input terminals 12, 24 from an optical star coupler output fiber. The irradiated light source of the branch side of the tree form communication network is constituted that a wavelength different from the wavelength of the light source of devices connected to the coupler at the branch side and receptionable by the devices is outputted. Further, a filter 22 for eliminating wavelength lambdaR is provided to the input terminal 24 of the repeater 21. Then, the light transmission wavelength lambdaR of the coupled output of the repeater 21 is made different from the light transmission wavelength lambdaT at the terminal device so as to stabilize the communication in the tree form communication network. |
