Compared to the rapid development of design methods, the optimization of the GeSbSe layer design is still lagging behind. Accordingly, the layer design should be acceptable for existing methods. Optimum selection of GeSbSe layer design in connection to transmission and thickness choice is discussed. The Ge_xSb_{40  −  x}Se₆₀ (x  =  12, 25, and 30 at.%) were synthesized from elements with 5N purity (Ge, Sb, and Se) using the conventional melt-quenching method. The experimental measurements are obtained in spectral range 250 to 1700 nm using spectrophotometer UV-VIS Lambda correlated with theoretical simulation obtained by OpenFilters. OpenFilters allows the creation of a material with higher transmission and low thickness for the possible applications in infrared transmitting filters and three-level phase-change memory.