OPTICAL WAVEGUIDE GRATING COUPLER INCORPORATING REFLECTIVE OPTICAL ELEMENTS AND ANTI-REFLECTION ELEMENTS

摘要

An optical wavelength grating coupler (102) incorporating one or more distributed Bragg reflectors (DBR) (434) or other reflective elements to enhance the coupling efficiency thereof. The grating coupler (102) has a grating (408) comprising scattering elements (103), and the one or more DBRs (434) are positioned with respect to the grating such that light passing through the grating towards the substrate (414) of the grating coupler (102) is reflected back by DBRs toward the grating. The DBR (434) comprises a multilayer stack of various materials and may be formed on the substrate (414). The grating coupler (102) may include a gas-filled cavity (472), where the cavity is formed by a conventional etching process and is used to reflect light toward the grating (408). The grating coupler (102) may also incorporate an anti-reflection coating (486) to reduce reflective loss on the surface of the grating.