To provide an optical transmission system, which can be more inexpen sively constructed and can deal with the increase in the transmission capacity, by connecting plural node stations while having wavelength transmissivity on a ring-shaped optical transmission line.
N pieces of anode stations 34-1 to 34-N are connected on an optical transmission line 32 composed of a pair of optical fiber lines 32a and 32b. In a center station 30, two pieces of communication terminal equipment 36A and 36B are connected to both the ends of the optical fiber lines 32a and 32b. The communication terminal equipment 36A and 36B have the same configuration. Wavelength λR1-λRN assigned to the respective node stations 34-1 to 34-N for reception are used for signal transmission from the center station 30 to the respective node stations 34-1 to 34-N and wavelengths λT1-λTN assigned to the respective node stations 34-1 to 34-N for transmission are used for the reverse direction. A transmission band on the optical fiber lines 32a and 32b is bisected, the reception wavelength λR1-λRN are arranged in one band and the transmission wavelength λT1-λTN are arranged in the other band. The respective node stations 34-1 to 34-N are respectively connected to the optical fiber lines 32a and 32b by 2×2 photocouplers 52 and 54.
NAGAO YASUYUKI
YAMAMOTO SHU
RYU SHIRO
