New systems and methods for wavelength locking for a class of multi-wavelength laser sources (MWLS) are provided. In this type of MWLS, the set of output wavelength channels are produced from a limited number of initial laser sources, such as a single laser or dual laser. In this invention, the initial lasers are locked based on the wavelengths of the outer channels in the set of output channels to provide tighter channel locking than that of a single laser source. This is mainly possible since the error in channel spacing caused by channel wavelength offset of the seed lasers is amplified by channel multiplication done in MWLS. This provides better resolution than applying wavelength locking to the seed lasers.