Multichannel duplex fiber-optic communication line operating at the wavelength of ~1.3 μ

A prototype was developed of a multichannel duplex fiber-optic communication line with spectral multiplexing in the region of 1.3 μ. The line length was 5 km and it provided simultaneous communication by two optical carriers in one direction and two in the opposite direction; the spectral interval between the carriers traveling in the same direction was 17 nm. At each end of the line there was a diffraction grating which was used for multiplexing and demultiplexing; it ensured formation of narrow-band optical carriers in the multiplexing stage. The terminal devices were capable of multiplexing of ten channels traveling simultaneously in the same direction.