Active photonic devices incorporating high dielectric constant materials
A waveguide structure includes a substrate and a waveguide core coupled to the substrate and including a first material characterized by a first index of refraction and a first electro-optic coefficient. The waveguide structure also includes a first cladding layer at least partially surrounding the waveguide core and including a second material characterized by a second index of refraction less than the first index of refraction and a second electro-optic coefficient greater than the first electro-optic coefficient. The second cladding layer is coupled to the first cladding layer.
1. A waveguide structure comprising:
a substrate;
a waveguide core coupled to the substrate and including a first material characterized by a first index of refraction and a first electro-optic coefficient;
a first cladding layer at least partially surrounding the waveguide core and including a second material characterized by a second index of refraction less than the first index of refraction and a second electro-optic coefficient greater than the first electro-optic coefficient; and
a second cladding layer coupled to the first cladding layer, wherein the first cladding layer is disposed between the waveguide core and the second cladding layer.
2. The waveguide structure of claim 1 wherein the second cladding layer includes a third material characterized by a third electro-optic coefficient greater than the first electro-optic coefficient.
3. The waveguide structure of claim 2 wherein the second electro-optic coefficient and the third electro-optic coefficient are greater than or equal to an electro-optic coefficient for silicon.
4. The waveguide structure of claim 2 wherein the third electro-optic coefficient is less than the second electro-optic coefficient.
5. The waveguide structure of claim 2 wherein the first cladding layer comprises 200 nm of the second material proximal to the waveguide core and the second cladding layer comprises 2 μm of the third material distal to the waveguide core.
6. The waveguide structure of claim 1 wherein the waveguide core comprises silicon, the first cladding layer comprises tantalum oxide, and the second cladding layer comprises silicon dioxide.
7. The waveguide structure of claim 1 wherein the second material is characterized by a χ (3) value greater than 2.2×10 −18 m 2 /W.
8. The waveguide structure of claim 1 wherein the second material comprises tantalum oxide (Ta 2 O 5 ).
9. The waveguide structure of claim 1 wherein the second material is characterized by a χ (2) value greater than zero.
10. The waveguide structure of claim 9 wherein the χ (2) value is greater than 10 pm/V.
11. The waveguide structure of claim 10 wherein the χ (2) value is greater than 100 pm/V.
12. The waveguide structure of claim 9 wherein the second material comprises at least one of lead zirconate titanate (PZT) or barium titanate (BaTiO 3 ).
13. The waveguide structure of claim 1 wherein the waveguide structure comprises a Mach-Zehnder interferometer.
14. The waveguide structure of claim 1 wherein the waveguide structure comprises a ring resonator.
15. A switch structure with a positive DC Kerr effect and positive Pockels effect, the switch structure comprising:
at least one optical input port;
at least one optical output port;
a waveguide structure, wherein the waveguide structure is optically coupled to the at least one optical input port, and wherein the waveguide structure comprises:
a substrate;
a waveguide core coupled to the substrate and including a first material characterized by a first index of refraction and a first electro-optic coefficient;
a first cladding layer at least partially surrounding the waveguide core and including a second material characterized by a second index of refraction less than the first index of refraction and a second electro-optic coefficient greater than the first electro-optic coefficient; and
a second cladding layer coupled to the first cladding layer.
16. The switch structure of claim 15 wherein the first electro-optic coefficient and the second electro-optic coefficient are the Kerr coefficient χ (3) .
17. The switch structure of claim 15 wherein the first electro-optic coefficient and the second electro-optic coefficient are the Pockels coefficient χ (2) .
18. The switch structure of claim 15 wherein the waveguide core supports a guided mode characterized by an optical power and a majority of the optical power is contained in the waveguide core.
19. The switch structure of claim 15 wherein the waveguide core comprises silicon.
20. The switch structure of claim 15 further comprising:
a first electric contact and a second electrical contact configured to generate an applied electric field produced in the waveguide structure that is characterized by a direction; and
at least one of the first cladding layer or the second cladding layer is characterized by an electro-optic coefficient tensor having a maximum value aligned along the direction.