We describe an optical system developed to form the basis of a 64 x 64 free-space optical matrix-matrix crossbar switch. The design and performance of each of the main optical components is discussed: lenses, diffractive optical elements, and polarizing beamsplitters, together with the optomechanical hardware design. For these components, throughput levels of -6.9 dB have been achieved, which is compatible with full system operation at 10(-12) bit error rates at greater than or equal to 270 Mbits s(-1). (C) 1996 Optical Society of America