Shashlyk calorimeter technology, based on a sampling structure of alternating scintillator and absorber layers read out by plastic wavelength-shifting fibers, provides an effective solution for electromagnetic calorimetry in high-intensity physics experiments. This choice is motivated by its good energy resolution, fast time response, mechanical simplicity, and operational reliability, as demonstrated in several large-scale detectors. This work presents the development and test of highly segmented shashlyk calorimeter prototypes, validated through a detailed Geant4 simulation including optical photon transport.