The design of a bidirectional free-space optical interconnect system is presented. Vertical-cavity surface-emitting laser (VCSEL) arrays as a coherent light source and VCSEL beam collimation are described. Hologram array design and a way to improve the diffraction efficiency by use of a copying technique utilizing Dupont photopolymers are presented. Scattering from the hologram as a noise source is measured. An optical model for the design of system parameters such as the VCSEL beam diameter, size and apodization of the hologram, and size of the detector is given on the basis of cross-talk analysis of the system. The effect of VCSEL wavelength variation on system design is considered. Aberrations caused by the Fourier lens in the system are calculated, and ways for correction of the aberrations are discussed.