Method for generating an optimized return-to-zero pulse shape against aggressive optical filtering and an optical transmitter implementing the method

An optical transmitter, comprising:

• first and second sets of optical in-phase and quadrature modulators, each set being coupled to a respective pair of electrical amplifiers for receiving two respective input signals;
• an integrable tunable laser assembly that is configured to generate a continuous-waveform optical signal;
• a first polarization beam splitter that is configured to divide the continuous-waveform optical signal into a x-polarized tributary and a y-polarized tributary, wherein each of the x-polarized tributary and the y-polarized tributary is modulated by one of the first and second sets of optical in-phase and quadrature modulators in accordance with the two respective input signals applied to the respective pair of electrical amplifiers;
• a second polarization beam splitter that is configured to combine the modulated x-polarized tributary and the modulated y-polarized tributary into one optical signal;
• and
• an optical modulator that is configured to modulate the combined optical signal using a driving voltage, wherein the driving voltage has a bias point that is reduced by a predefined offset from a predefined reference voltage level.