Grating coupler

A grating coupler is a diffractive structure on the surface of a photonic chip that lets light from an optical fiber (arriving nearly perpendicular to the chip) couple into a waveguide guiding light in the plane of the chip.

How does a grating coupler work?

The periodic diffraction-grating structure etched into the waveguide bends the incoming light at an angle that allows it to propagate along the waveguide. Key design parameters are coupling efficiency, spectral bandwidth, and tolerance to fiber incidence-angle deviation.

Applications

Grating couplers are a standard input/output interface in photonic integrated circuits, used for wafer-level testing during production as well as in final optical transceiver modules.

Related terms

Optical waveguide

PIC (Photonic Integrated Circuit)

FDTD