Laterally coupled semiconductor quantum dot (QD) arrays emerged recently as promising structures for the next generation of high efficiency intermediate band solar cell (IBSC).We present here a method based on multi-band k.p Hamiltonian combined with periodic boundary conditions, applied to predict the electronic and optical properties of InAs/GaAs QDs based lateral QD arrays. The absorption coefficients were used to estimate the corresponding photovoltaic conversion efficiencies using the drift-diffusion transportation theory. Special attention was paid on the transition between IB to continuum states in conduction band. By comparing the experimental and theoretical results we have confirmed operation of the InAs/GaAs QD array based solar cell in the intermediate band regime.