Silicon-based optical antenna with reflective layer and preparation method therefor
Embodiments of the present disclosure provide a silicon-based optical antenna with a reflective layer and a preparation method therefor. The silicon-based optical antenna comprises: an SOI substrate, the SOI substrate at least comprises a bottom silicon layer, a buried oxide layer, and a top silicon layer, the buried oxide layer is located between the bottom silicon layer and the top silicon layer, the top silicon layer is etched to form a row of waveguides, spacings between the waveguides in the row of the waveguides are in an uneven distribution, each waveguide of the row of the waveguides is etched with gratings, the bottom silicon layer is formed with a groove directly reaching a surface of the buried oxide layer facing the bottom silicon layer, and the surface of the buried oxide layer in the groove is formed with a metal reflective layer.
1. A silicon-based optical antenna with a reflective layer, wherein the optical antenna comprises: a silicon-on-insulator (SOI) substrate, the SOI substrate at least comprises a bottom silicon layer, a buried oxide layer, and a top silicon layer, the buried oxide layer is located between the bottom silicon layer and the top silicon layer, the top silicon layer is etched to form a row of waveguides, spacings between the waveguides in the row of the waveguides are in an uneven distribution, each waveguide of the row of the waveguides is etched with gratings, the bottom silicon layer is formed with a groove directly reaching a surface of the buried oxide layer facing the bottom silicon layer, and the surface of the buried oxide layer in the groove is formed with a metal reflective layer;
the gratings on the waveguides are combined into a two-dimensional diffraction grating; when optical waves enter a region where the two-dimensional diffraction grating is located, refraction and reflection are formed on the gratings, wherein refracted optical waves emit from the gratings and form coupling in a free space; when the optical waves reflected by the gratings reach the metal reflective layer, the optical waves are reflected back by the metal reflective layer, so that the optical waves enter the free space, to further coupling with the foregoing optical waves refracted into the free space.
2. The optical antenna according to claim 1 , wherein a region where the metal reflective layer is located corresponds to a region where the gratings are located and is larger than the region where the gratings are located.
3. The optical antenna according to claim 1 , wherein a thickness of the metal reflective layer corresponds to a metal material of the metal reflective layer and a wavelength emitted by the optical antenna.
4. The optical antenna according to claim 1 , wherein the row of waveguides is a row of waveguides arranged horizontally.
5. The optical antenna according to claim 1 , wherein the row of waveguides comprises multiple waveguides in a horizontal plane and arranged in parallel.
6. The optical antenna according to claim 1 , wherein the spacings between the waveguides in the row of the waveguides are in an Gaussian distribution, wherein the spaces between the waveguides in a center of the row of the waveguides are denser, and the spaces between the waveguides in both sides of the row of the waveguides are sparser.
7. A preparation method for a silicon-based optical antenna with a reflective layer, comprising:
acquiring a silicon-on-insulator (SOI) substrate, the SOI substrate at least comprising a bottom silicon layer, a buried oxide layer, and a top silicon layer;
etching the top silicon layer to form a row of waveguides, and etching each waveguide of the row of the waveguides with gratings, wherein spacings between the waveguides in the row of the waveguides are in an uneven distribution;
etching the bottom silicon layer to form a groove corresponding to a region where the gratings are located and directly reaching a surface of the buried oxide layer facing the bottom silicon layer, and forming a reflective surface on a surface of the buried oxide layer in the groove; and
depositing a metal reflective layer on the reflective surface;
wherein, the gratings on the waveguides are combined into a two-dimensional diffraction grating; when optical waves enter a region where the two-dimensional diffraction grating is located, refraction and reflection are formed on the gratings, wherein refracted optical waves emit from the gratings and form coupling in a free space; when the optical waves reflected by the gratings reach the metal reflective layer, the optical waves are reflected back by the metal reflective layer, so that the optical waves enter the free space, to further coupling with the foregoing optical waves refracted into the free space.
8. The preparation method according to claim 7 , wherein a region covered by the metal reflective layer is larger than a corresponding region where the gratings are located.
9. The preparation method according to claim 7 , wherein a thickness of the metal reflective layer corresponds to a metal material of the metal reflective layer and a wavelength emitted by the optical antenna.
10. The preparation method according to claim 7 , further comprising:
growing a SiO 2 protective layer on the region where the gratings of the SOI substrate are located.
11. The preparation method according to claim 7 , wherein the row of the waveguides is a row of waveguides arranged horizontally.
12. The preparation method according to claim 7 , wherein the row of the waveguides comprises multiple waveguides in a horizontal plane and arranged in parallel.
13. The preparation method according to claim 7 , wherein the spacings between the waveguides in the row of the waveguides are in an Gaussian distribution, wherein the spaces between the waveguides in a center of the row of the waveguides are denser, and the spaces between the waveguides in both sides of the row of the waveguides are sparser.