| 摘要 |
PROBLEM TO BE SOLVED: To attain effective use of an optical transmission line, to reduce the cost of the transmitter and to enhance the maintainability by configuring a branch means that transmits a wavelength multiplex signal light after amplification to an opposite optical transmission line to that through which the signal light has been sent with an optical branching device and optical fiber gratings so as to attain narrow band wavelength multiplex. SOLUTION: A wavelength multiplex signal light with wavelength bands of λ1-λ8 outputted from a wavelength multiplex transmission optical amplifier 3 is distributed into two by an optical branching device 4. Then the wavelength of each of the divided wavelength multiplex signal lights to be sent to each of optical transmission lines A, B is selected by utilizing an optical filter characteristic of optical fiber gratings 51-58. The wavelength multiplex signal light with the wavelength bands of λ5-λ8 among the wavelength multiplex signals with the wavelength bands of λ1-λ8 is individually reflected in the optical fiber gratings 51-58 and only the wavelength multiplex signal light with wavelength bands of λ1-λ4 passes on the optical fiber gratings 55-58. Thus, the wavelength of the light is selected and transmitted onto the optical transmission line B. |
