In this paper, we address the problem of designing wavelength division multiplexing (WDM) optical interconnects with reduced hardware complexity. We propose a new WDM optical interconnect design that reduces both the number of space switches and the cost of wavelength conversion. Wavelength conversion in the proposed design occurs between two predefined wavelengths, eliminating the need for expensive wide-range wavelength converters used in most existing designs. In addition, the proposed design follows the recursive structure of the Benes network, and hence, scalability occurs in an orderly fashion. A systematic method for developing interconnects with arbitrary number of wavelengths and fibers is given, and the main properties of the new design are analyzed and compared with existing designs. We show that, the new design requires the minimum number of switching stages and space switches compared to any existing WDM Benes interconnect. Moreover, our design has minimum wavelength conversion cost compared to most existing designs.