Optical device having modulator employing horizontal electrical field
View Patent ↗The optical device includes a waveguide on a base. The device also includes a modulator on the base. The modulator includes an electro-absorption medium configured to receive a light signal from the waveguide. The modulator also includes field sources for generating an electrical field in the electro-absorption medium. The electro-absorption medium is a medium in which the Franz-Keldysh effect occurs in response to the formation of the electrical field in the electro-absorption medium. The field sources are configured so the electrical field is substantially parallel to the base.
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 modulator positioned on the base,
the modulator including an electro-absorption medium having lateral sides that each extends between a top side and a bottom side, the bottom side being between the base and the top side,
the electro-absorption medium configured to receive at least a portion of the light signal from the light-transmitting medium in the waveguide,
the light-transmitting medium and the electro-absorption medium being different materials,
field sources configured to serve as sources of an electrical field in the electro-absorption medium,
the electro-absorption medium being a medium in which the Franz-Keldysh effect occurs in response to the formation of the electrical field in the electro-absorption medium,
the field sources each being a doped region of the electro-absorption medium and the field sources each contacting one of the lateral sides and the lateral sides that are contacted by the field sources being on opposing sides of the electro-absorption medium.
2. The device of claim 1 , wherein each of the lateral sides contacted by one of the field sources is perpendicular to the base.
3. The device of claim 1 , wherein the light-transmitting medium and the electro-absorption 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.
4. The device of claim 3 , wherein the angle is between 80° and 89°.
5. The device of claim 1 , wherein a seed portion of the light-transmitting medium is positioned between the electro-absorption medium and the base, and
the electro-absorption medium contacts the seed portion of the light-transmitting medium.
6. The device of claim 1 , wherein each of the field sources spans a distance between a top of the lateral side contacted by the field source and the bottom of the lateral side contacted by the field source.
7. The device of claim 1 , wherein each of the field sources extends from a top of the lateral side contacted by the field source toward the base.
8. The device of claim 1 , wherein each of the field sources extends toward the base from a location that is above 90% of a distance between a top of the lateral side contacted by the field source and the bottom of the lateral side contacted by the field source.
9. The device of claim 1 , wherein each of the field sources extends toward the base from a location that is within 1 μm of a top of the lateral side.
10. The device of claim 1 , wherein the waveguide includes a horizontal taper positioned such that the waveguide travels directly from the taper to the modulator.
11. The device of claim 1 , wherein the modulator includes a ridge extending from slab regions positioned on opposing sides of the ridge and the electro-absorption medium being included in the ridge and also in the slab regions.
12. The device of claim 11 , wherein the doped regions are positioned on opposing sides of the ridge.
13. The device of claim 11 , wherein the electro-absorption medium included in each slab region is continuous with the electro-absorption medium included in the ridge.
14. The device of claim 11 , wherein one or more of the doped regions is included in both the ridge and one of the slab regions.
15. The device of claim 11 , wherein one or more electrical contacts is positioned on the electro-absorption medium included in one of the slab regions.
16. The device of claim 11 , wherein electrical contacts are each positioned on the electro-absorption medium included in one of the slab regions such that the ridge is positioned between the electrical contacts.