Wavelength division multiplexed system employing optimal channel modulation

An apparatus for transmitting a WDM optical data signal having a plurality of data channels, comprising:

• a plurality of transmitter units each generating one of said data channels, each of said transmitter units including:
• an optical signal source for generating an optical channel onto which data is modulated at a predetermined frequency to provide a data modulated optical channel;
• an amplitude modulator coupled to the optical signal source for modulating said data modulated optical channel;
• a clock coupled to the amplitude modulator having a frequency that determines the modulation frequency imparted to the data modulated optical channel by the amplitude modulator, said frequency of the clock being phase locked and equal to said predetermined frequency at which data is modulated;
• and
• wherein said amplitude modulators respectively modulate said data modulated optical channels with a waveform independently adjustable from one another.