Wavelength division multiplexed optical communication system having variable channel spacings

A system, comprising:

• a first transmitter including:
• a first digital signal processor circuit configured to receive input data, the digital signal processor being configured to sample the input data at a first sampling rate, and spectrally shape the input data to supply spectrally shaped data as a first plurality of data samples at the first sampling rate,
• a first interpolation circuit that receives the first plurality of data samples at the first sampling rate and outputs the spectrally shaped data as a second plurality of data samples at a second sampling rate greater than the first sampling rate,
• a digital-to-analog converter circuit configured to receive the second plurality of data samples and generate an analog signal,
• a modulator circuit, and
• a laser configured to supply light to the modulator circuit, the modulator circuit being configured to modulate the light to supply a first modulated optical signal in response to the analog signal,
• a second transmitter supplying a second modulated optical signal;
• a combiner configured to combine the first modulated optical signal with the second modulated optical signal onto an optical communication path;
• and
• a receiver coupled to the optical communication path, the receiver including:
• a photodiode that receives portions the first and second modulated optical signals, the photodiode supplying an electrical output,
• a low-pass filter that supplies a filtered output in response to the electrical output,
• an analog-to-digital converter configured to sample the filtered output at the second sampling rate to generate a plurality of third data samples,
• a second interpolation circuit configured to receive the plurality of third data samples and supply a plurality of fourth data samples at a third sampling rate less than the second sampling rate, and
• a second digital signal processor circuit configured to receive the plurality of fourth data samples.