An example system for multi-wavelength optical signal splitting is disclosed. The example disclosed herein comprises a first splitter, a second splitter, and a modulator. The system receives a multi-wavelength optical signal and an electrical signal, wherein the multi-wavelength optical signal comprises a plurality of optical wavelengths and has a power level. The first splitter is to split the plurality of optical wavelengths into a plurality of optical wavelength groups. The second splitter is to split the multi-wavelength optical signal or the plurality of optical wavelength groups into a plurality of lower power signal groups. The modulator is to encode the electrical signal into the plurality of optical wavelength groups, the plurality of lower power signal groups, or a combination thereof.