Optical device having light sensor employing horizontal electrical field
View Patent ↗The device includes an optical waveguide on a base. The waveguide is configured to guide a light signal through a light-transmitting medium. A light sensor is also positioned on the base. The light sensor including a ridge extending from slab regions. The slab regions are positioned on opposing sides of the ridge. A light-absorbing medium is positioned to receive at least a portion of the light signal from the light-transmitting medium included in the waveguide. The light-absorbing medium is included in the ridge and also in the slab regions. The light-absorbing medium includes doped regions positioned such that an application of a reverse bias across the doped regions forms an electrical field in the light-absorbing medium included in the ridge.
1. An optical device, comprising:
a waveguide on a base, the waveguide configured to guide a light signal through a light-transmitting medium; and
a light sensor positioned on the base,
the light sensor including
a ridge extending from slab regions, the slab regions being on opposing sides of the ridge,
a light-absorbing medium positioned to receive at least a portion of the light signal from the light-transmitting medium in the waveguide,
the light-absorbing medium being included in the ridge and also in the slab regions,
the light-transmitting medium and the light-absorbing medium being different materials,
the light-absorbing medium including doped regions positioned such that an application of a reverse bias between the doped regions forms an electrical field in the light-absorbing medium included in the ridge.
2. The device of claim 1 , wherein the doped regions are positioned on opposing sides of the ridge.
3. The device of claim 1 , wherein the light-absorbing medium included in each slab region is continuous with the light-absorbing medium included in the ridge.
4. The device of claim 1 , wherein the light-absorbing medium included in each slab region is continuous with the light-absorbing medium included in the ridge.
5. The device of claim 1 , wherein one or more of the doped regions is included in both the ridge and one of the slab regions.
6. The device of claim 1 , wherein one or more electrical contacts is positioned on the light-absorbing medium included in one of the slab regions.
7. The device of claim 1 , wherein electrical contacts are each positioned on the light-absorbing medium included in one of the slab regions such that the ridge is positioned between the electrical contacts.
8. The device of claim 7 , wherein each electrical contact contacts the light-absorbing medium.
9. The device of claim 1 , wherein at least a portion of the electrical field can form on a path from one of the slab regions, through light-absorbing medium under the ridge, and then to another one of the slab regions without entering the light transmitting medium.
10. The device of claim 1 , wherein the light-transmitting material is between the light-absorbing medium included in the ridge and the base.
11. The device of claim 1 , wherein the light-transmitting material is between the light-absorbing medium included in the slab regions and the base.
12. The device of claim 1 , wherein the light-transmitting material is between the light-absorbing medium included in the ridge and the base and also between the light-absorbing medium included in each of the slab regions and the base.
13. The device of claim 1 , wherein the light-absorbing medium included in the ridge has a top side between lateral sides and each of the doped regions contacts one of the lateral sides.
14. The device of claim 1 , wherein a portion of the light-absorbing medium included in the ridge is between doped regions and is undoped.
15. The device of claim 1 , wherein the light-absorbing material includes germanium.
16. The device of claim 1 , wherein the light-transmitting medium and the light-absorbing medium contact one another at an interface, the interface being configured such that the light signal travels through the interface, the interface being at a non-perpendicular angle relative to a direction of propagation of the light signals through the waveguide at the interface.
17. The device of claim 16 , wherein the angle is between 80° and 85°.