In this paper the method for reducing the shift of the "clock" resonance by the example of 87 Sr has been described. This shift arises due to the presence in the optical spectrum of the lattice laser of the incoherent component. This component is a traveling wave. It is shown that the effective decrease of the impact on the shift of the "clock" resonance by introducing the interference filter is achieved. This filter was inserted directly into the optical scheme after the laser source. Examples of the optical lattice spectra with and without filter are considered. The estimates of the efficiency ratio of the use of the interference filters to improve the final uncertainty of the optical reference are made. It is shown that the filter reduces the relative uncertainty from the impact of the incoherent component of the optical radiation of the optical lattice by two orders of magnitude. It should help to reduce the lower bound for the total uncertainty limit of the optical frequency clocks down to 10 −18 .