(US4747649-A)      The monolithically integrated wavelength demultiplexing module, comprises a film wave guide for guiding a light beam containing several wavelengths and a wavelength selector is in the waveguide for splitting the light beam into the respective wavelength components and directing the components in different directions through the film waveguide. A number of photodetectors are optically coupled to the film wave guide and respectively positioned to receive respective ones of the components. A common substrate carries the wave guide, the wavelength selector and the photodetectors. The substrate comprises InP, and the film wave guide comprises a quaternary layer.    A reflective element extends transversely relative to the film wave guide and obliquely to the propagation direction of a radiation component to be received by a photodetector, and the reflective element reflects the radiation passing the photodetector in the direction toward the photo detector. (8pp)e    (EP187979-B1)      Monolithically integrated wavelength demultiplex module, there being formed on a common substrate (1) - a film waveguide (10) for guiding radiation containing a plurality of wavelengths (lambda 1, lambda 2), - a wavelength-selecting element (20) for splitting the radiation guided in the film waveguide (10) and propagating in a particular direction (12) into radiation components containing mutually different wavelengths (lambda 1, lambda 2) and propagating in different directions (131, 132) in the film waveguide (10), and - a plurality of photodetectors (31. 32) which are optically coupled to the film waveguide (10) and receive radiation components containing in each case one of the mutually different wavelengths and propagating in different directions, characterised in that the substrate (1) is composed of InP and the film waveguide (10) is composed of a quaternary layer, and in that the photodetector (31, 32) optically coupled to the film waveguide (10) by means of a leaky wave coupling has one or more ternary layers (13) which have different dopings and are applied directly onto the film waveguide (10).