Integrated optical multiplex-demultiplex module for optical communications transmission

Claim 1

In an integrated optical multiplex-demultiplex module particularly useful for bi-directional optical communication transmissions, said module having a substrate with a laser diode and a strip waveguide for guiding output from the laser diode to an out-coupling region disposed on one surface of the substrate and a photodetector arranged on an opposite surface of the substrate, a frequency-selective grating being arranged in said waveguide and said frequency-selective grating essentially not influencing the guided laser diode emissions traveling in the waveguide to an in-coupling region but deflecting a wavelength different than the wavelength of the laser diode emissions into a second waveguide extending from the first mentioned waveguide and a diffraction grating having grid lines proceeding perpendicular relative to the propagation direction of the radiation of this other wavelength traveling in the second waveguide, said diffraction grating directing the other wavelength onto the photodetector, the improvements comprising said frequency-selective grating and said diffraction grating being formed by a common single grating, which is fashioned on the first waveguide leading from the laser diode to the out-coupling and in-coupling regions, said single grating having grid lines extending perpendicular to the propagation direction of the light in said first waveguide.