Compact, Broadband, and Wide-Angle Optical Coupling for Silicon Waveguide

Compact, Broadband, and Wide-Angle Optical Coupling for Silicon Waveguide

Blog Article

A novel grating coupling scheme with simultaneously broadband and wide-angle efficiency for unidirectionally coupling freely propagating light into a silicon waveguide is proposed and theoretically investigated.The coupling structure is composed of two cascaded subgratings with proper spectral and angular intervals.A semi-analytical theory based on coupled-mode model is developed to facilitate the design.Proof-of-principle demonstrations show that the spectral and angular Circuit Board full-width half-maximums (FWHMs) are simultaneously broadened to nearly three times at a specific wavelength or incidence angle, compared with the reference grating of the same number of periodic features.The spectral FWHM reaches 200 nm, covering E + S + C or C + L + U communication bands, and meanwhile, the angular FWHM is up to 8°; if the spectral FWHM is diminished to 40 nm only cheeks balm covering C band, the angular FWHM will be as large as 40°.

This paper may be of great interest in related applications such as biochemical sensing and optical interconnect.