Multi-wavelength light detecting and/or emitting apparatuses having serially arranged grating directional couplers

摘要

In a multi-wavelength light detecting and/or emitting apparatus, there are provided of a first unit of a first directional coupler having a grating for an optical coupling function and a photodetector having a photoelectric conversion function and a second unit of a second directional coupler having a grating for an optical coupling function and a semiconductor laser, and a common light waveguide extending parallel with the unit in a light propagating direction. The first directional coupler and the photodetector are serially arranged in the light propagating direction and parallel with the common light waveguide, and the second directional coupler and the semiconductor laser are serially arranged in the light propagating direction and parallel with the common light waveguide. When there are formed a plurality of the first units and the gratings have different pitches, wavelength multiplexed light signals can be simultaneously detected per each wavelength with an equal detection performance. When there are formed a plurality of the second units and the gratings have different pitches, laser lights of different wavelengths can be emitted from a single emission end of the common waveguide and the semiconductor lasers can be independently driven.