ABSTRACT
Adjustment of the digital source signal to the properties and transmission behavior of the optical transmission channel takes place by means of selected pulse shaping in the transmitter filter. Transmission in the optical long wavelength range is technologically feasible, and it is possible to operate systems in which there is low or minimal fiber attenuation and relatively low residual dispersion, thus permitting a considerable increase in the bit rate-distance product attainable. A laser diode is used to produce the optical signal. It is essential to avoid modal dispersion and modal noise to achieve highest transmission rates with maximum repeater spacing for a given bit error rate; therefore single-mode (SM) fibers must be used. The optical transmission signal, processed as required in order to obtain transmission as error-free as possible, is fed into the transmission medium using the appropriate coupling elements. The maximum amplitude of the transmission pulse is obtained by means of the maximum laser output for dynamic SM behavior.
