An arrangement for multiplexing and/or demultiplexing optical signals having a plurality of wavelengths, including a multiplex body having two parallel surfaces between which light is reflected back and forth and in this case is coupled in or out in a wavelength-dependent manner, and structures for coupling optical signals into or out of the multiplex body. According to the invention, the structures for coupling optical signals into or out of the multiplex body have a plurality of essentially structurally identical subassemblies, each subassembly having an optoelectronic transducer and an associated optical system, by which light having a wavelength is respectively coupled into or out of the multiplex body.