| 摘要 |
PURPOSE:To obtain a photo branching, coupling decice which prevents occurrence of crosstalk and does not cause interference, by providing a light transmitting body for feedback on the end face of a self-converging lens to converge optical signals of other than specified wavelength, and feeding back the optical signals of other than specified wavelength. CONSTITUTION:A fiber 17 to send signals of wavelength lambda1-lambdan to be transmitted from a central station and a fiber 21 for feedback are symmetrically installed with respect to the axis of a lens 15. Even if transmission light from a terminal station 19 is partly reflected by a filter 16, the reflected light does not enter the light receiving part of the own station, crosstalk due to received light does not occur, so that reduction of S/N ratio may be prevented. Since the light of other than wavelength lambda1 reflected by the filter 16 is reflected twice by the filter, the light of wavelength lambda1 transmitted from the central station is transmitted in a larger quantity, so that interference may be prevented. Therefore, since the optical signal transmitted from the own station does not enter the receiving fiber of the own station, crosstalk may be prevented. |
