Dead spaces are generated in the fast-axis direction of the laser diode stack (LDS) because of the construction of the LDS. A new method of using a plane-parallel plate array to eliminate dead spaces between the bars of the LDS is presented. The design method of the plane-parallel plate is also investigated, and the beam parameter product is used to evaluate the quality of the beams. As an example, the plane-parallel plate array for an LDS consisting of four bars is designed and simulated. The simulation results show that the dead spaces are eliminated, the spots size is compressed from 6.5 mm X 10 mm to 3.5 mm X 10mm, and the energy loss is about 2%. (C) 2007 Society of Photo-Optical Instrumentation Engineers.