This invention is suited for applications in communications, radar, broadcasting and astronomy.
Conventional vertical couplers are designed to be large to maximize coupling efficiency. This size limits the coupler bandwidth and usefulness for other application, such as Optical Phased Arrays (OPAs). Therefore, there is a need for compact couplers that have high coupling efficiency.
This invention is a frequency-chirped nano-antenna that provides efficient sub-wavelength vertical emission from a dielectric waveguide. This nano-antenna consists of a set of plasmonic dipoles (resonators) on the opposite side of a Si3N4 waveguide from a ground plane. The resulting structure, which is less than half a wavelength long, emits a broadband beam that can be coupled into an optical fiber. Because this coupling structure is short, it is suitable for vertical coupling in Silicon On Insulator (SOI) based Optical Phased Arrays (OPAs).
- Better coupling efficiency than traditional vertical couplers
- Reduced element size