TWIN WAVEGUIDE BASED DESIGN FOR PHOTONIC INTEGRATED CIRCUITS

摘要

An asymmetric twin waveguide (ATG) structure (11) significantly reduces the negative effects of inter-modal interferences in symmetric twin-waveguide structures and which can be effectively used to implement a variety of optic al devices. The ATG structure (11) of the invention can be monolithically fabricated on a single epitaxial structure without the necessity of epitaxia l re-growth. The effective index of the passive waveguide in the ATG is varied from that of a symmetric twin waveguide such that one mode of the even and o dd modes of propagation is primarily confined to the passive waveguide and the other to the active waveguide (71). The different effective indices of the t wo coupled waveguides result in the even and odd modes becoming highly asymmetric. The mode with the larger confinement factor in the active waveguide (71) experiences higher gain and becomes dominant. Furthermore, a grating region is incorporated atop the passive waveguide (125) to select certain frequencies for transmission of light through the passive waveguide (125).