Abstract: This paper evaluate the multilevel modulation for
different techniques such as amplitude shift keying (M-ASK), MASK,
differential phase shift keying (M-ASK-Bipolar), Quaternary
Amplitude Shift Keying (QASK) and Quaternary Polarization-ASK
(QPol-ASK) at a total bit rate of 107 Gbps. The aim is to find a costeffective
very high speed transport solution. Numerical investigation
was performed using Monte Carlo simulations. The obtained results
indicate that some modulation formats can be operated at 100Gbps
in optical communication systems with low implementation effort
and high spectral efficiency.