| 摘要 |
A novel germanium (Ge) photodetector is disclosed, containing a stripe layer including Ge, a substrate supporting the stripe layer, and P and N regions, which are located inside the substrate and near opposite sides of the stripe. The stripe layer containing Ge for light absorption is operated in a slow-light mode by adding combinations of a gradual taper indent structure and a periodic indent structure to reduce light scatterings and to control light group velocity inside the stripe. Due to the slower light traveling velocity inside the stripe, the absorption coefficient of the stripe containing Ge is upgraded to be 1 to 2 orders of magnitude larger than that of a traditional bulk Ge at L band, and so the absorption coefficient reaches more than 1 dB/μm at the wavelength of 1600 nm. |
| 主权项 |
1. A photodetector having absorption enhanced under a slow-light mode, comprising
a silicon-on-insulator (SOI) substrate, said SOI substrate comprising an insulating layer and a Si island layer on top of said insulating layer, said Si island layer comprising a bulk-stripe layer interface and two flat surfaces, said two flat surfaces being separately located on two sides of said bulk-stripe layer interface; and a stripe layer containing Ge, said stripe layer being obtained on top of said Si island layer, said stripe layer comprising an upper surface, a first side surface and a second side surface, said second side surface is at opposite side of said first side surface, wherein said stripe layer has a gradual taper indent structure at a direction toward an light-inlet side and a periodic indent structure following said gradual taper indent structure, wherein said stripe layer is butt-coupled to a SOI waveguide, wherein a distance between said stripe layer and said SOI waveguide is 10 nm to 100 nm; and wherein a dielectric layer is located in said distance. |
