Fiber-optic communication line with multimode waveguides for data transfer over distances up to 8 km

A description is given of a fiber-optic communication line with multimode waveguides up to 8 km long. An experimental investigation was made of the influence of the waveguide parameters, conditions for their excitation, and of joints of the various segments of the waveguides on the attenuation and pass band of the whole line. The characteristic mode coupling length of the investigated waveguides (L_c=0.9±0.1 km) was determined together with the parameters representing the dependence of the pulse broadening on the waveguide length in the linear and squareroot parts of this dependence. The pass band of the 8-km line was 6.5 MHz and it agreed well with the value calculated from the parameters of the individual waveguide segments.