Modified Manchester modulation format for high‐speed optical transmission systems

Multilevel Manchester (2 bits/symbol) coding with optical equaliser for increasing the transmission distance of high‐speed fibre optic links

“…Therefore, four-level Manchester coding (4-MC) was proposed for the first time in [23] as a power-efficient alternative to four-level pulse amplitude modulation (4-PAM) for high-speed optical transmission systems. While four-level modified Manchester (4-MM) scheme was also developed and proposed for high-speed optical networks for the first time in [24] based on the performance of binary MM modulation presented in [25]. Therefore, the addition of OEQ to 4-MC and 4-MM systems further enhanced their overall performance thereby increasing transmission distance considerably.…”

Performance evaluation of four‐level modified Manchester modulation format for high‐speed optical transmission systems

“…Actually, a resourceful line coding must demonstrate satisfactory characteristics desirable for a specific application. Therefore, Manchester code adjudged the modest kinds of communication line codes, which offers a perfect synchronisation, and DC coupling that has been the most important restraint issue for digital transmission systems despite its desirable advantages above analogue transmission [15]. Hence, Manchester as a modulation technique remains an appealing and promising scheme in high-speed optical communication links.…”

“…the expansive spectral width that is accountable for the distortion of the spectral efficiency, which subsequently restricts the communication link considerably [19,20]. Hence, a modified Manchester (MM) modulation format was introduced for the first time in [15] as an alternative technique to the conventional Manchester modulation format, which offers a substantial improvement to the spectral efficiency with better dispersion tolerance for high-speed optical communication systems. The performance recorded in MM depends on the optimisation of the filter bandwidth together with the centre frequency; hence, the need for investigating the working principle of the multilevel MM scheme.…”