High-Performance Grating Coupler Array on Silicon for a Perfectly-Vertically Mounted Multicore Fiber

Vertical Coupling Between Waveguides and Optical Fibers Utilizing Polarization Gratings

“…In these methods asymmetry is introduced into the grating to enhance coupling efficiency in the vertical direction. Other options are using non-uniform periodic grating couplers [9][10][11], the implementing double-layer grating couplers [12,13] or making 2D variation of grating couplers [14] with the goal of achieving vertical coupling. These approaches demand the application of high-resolution deep ultraviolet (DUV) etch.…”

“…These approaches demand the application of high-resolution deep ultraviolet (DUV) etch. Furthermore, the attainment of low coupling loss necessitates materials that are not CMOS compatible, such as the inclusion of a Au reflective layer inside the SOI stack [11].…”

High-efficiency silicon nitride grating coupler for perfectly vertical coupling

“…Among them, perfectly vertical grating couplers are very promising since using them avoids adjustment of the fiber coupling angle during the test process which can further improve the characterization efficiency. At present, perfectly vertical grating couplers are mainly achieved on the SOI platform 7 . Due to the low refractive index contrast between silica and silicon nitride, it is still challenging to design an efficient silicon nitride grating coupler for perfectly vertical coupling.…”