Calculation of duobinary transmission systems with optical waveguides

A calculation and optimization method for optical waveguide transmission systems using the principle of digital duobinary transmission is presented. Then, systems with duobinary reception and systems with raised-cosine reception, which also need an equalizer at the receiving end, are compared with regard to the energy per single signal required for a tolerable bit error probability. Other criteria of comparison, such as susceptibility to jitter, additional duobinary system hardware, and error detection facilities, are considered, too. The results of the calculations show that in an optical waveguide transmission system where the duration of the signal at the optical waveguide output exceeds a defined value, the performance of the duobinary system is better than that of the raisedcosine system when the attainable repeater section lengths are compared.