Abstract: An integrated optical arrangement for multiplexing a plurality of different waveguide channels including a film waveguide disposed on a substrate having an arrangement for coupling a plurality of waveguide channels into the film waveguide, said film waveguide having a diffraction grating for separating the waveguide channels into a plurality of diffracted channels extending to a plurality of strip waveguides for conducting them from the film waveguide, and each of the strip waveguides having a photodetector in the form of an integrated diode for detecting the light being coupled from the film waveguide. The method includes providing a plurality of layers, removing the layers to form the diodes, further removing portions of the remaining layers to form the strip waveguides and film waveguides.