Engineered electro-optic devices
An electro-optic device includes a substrate and a waveguide on the substrate. The waveguide includes a layer stack including a plurality of electro-optic material layers interleaved with a plurality of interlayers and a waveguide core adjacent to the layer stack. The waveguide may include a pair of electrodes in electrical contact with the plurality of electro-optic material layers. The plurality of interlayers maintains a first lattice structure at room temperature and a cryogenic temperature. The plurality of electro-optic material layers maintains a second lattice structure and crystallographic phase at the room temperature and the cryogenic temperature.
1. A wafer comprising:
a substrate comprising silicon or germanium;
a buffer layer coupled to the substrate and configured to relieve stress within the wafer; and
a layer stack disposed on a top surface of the buffer layer, the layer stack including:
a plurality of electro-optic material layers; and
a plurality of interlayers interleaved with the plurality of electro-optic material layers,
wherein the plurality of interlayers maintains a first lattice structure at a room temperature and at a cryogenic temperature; and
wherein the plurality of electro-optic material layers are under tensile stress and maintain a second lattice structure and crystallographic phase at the room temperature and the cryogenic temperature.
2. The wafer of claim 1 , wherein the buffer layer comprises an oxidized layer of the substrate.
3. The wafer of claim 1 , wherein the plurality of electro-optic material layers are characterized by an in-plane polarization at the cryogenic temperature.
4. The wafer of claim 1 , further comprising an epitaxial seed layer between the buffer layer and the layer stack.
5. The wafer of claim 4 , wherein the epitaxial seed layer includes at least one of SrTiO 3 , LaAlO 3 , or MgO.
6. The wafer of claim 1 , wherein the plurality of electro-optic material layers is characterized by a tetragonal lattice structure at the cryogenic temperature.
7. The wafer of claim 1 , wherein the plurality of electro-optic material layers includes at least one of BaTiO 3 , (Ba,Sr)TiO 3 , Pb(Zr,Ti)O 3 , or (Pb, La)(Zr,Ti)O 3 .
8. The wafer of claim 1 , wherein the plurality of interlayers includes at least one of MgO, (Ba,Sr)TiO 3 , BaHfO 3 , BaZrO 3 , SrHfO 3 , SrZrO 3 , or SrNbO 3 .
9. The wafer of claim 1 , wherein a ratio between a first thickness of each of the plurality of electro-optic material layers and a second thickness of each of the plurality of interlayers is equal to or less than 20:1.
10. An electro-optic device comprising:
a substrate;
a waveguide disposed on top of the substrate;
a layer stack disposed on top of the waveguide and including a plurality of electro-optic material layers interleaved with a plurality of interlayers; and
a waveguide core disposed on top of a portion of the layer stack;
wherein the plurality of interlayers maintains a first lattice structure at a room temperature and at a cryogenic temperature; and
wherein the plurality of electro-optic material layers are under tensile stress and maintain a second lattice structure and crystallographic phase at the room temperature and the cryogenic temperature.
11. The electro-optic device of claim 10 , wherein the plurality of electro-optic material layers is characterized by a tetragonal lattice structure at the cryogenic temperature.
12. The electro-optic device of claim 10 , wherein the plurality of electro-optic material layers includes at least one of BaTiO 3 , (Ba,Sr)TiO 3 , Pb(Zr,Ti)O 3 , or (Pb, La)(Zr, Ti)O 3 .
13. The electro-optic device of claim 10 , wherein the plurality of interlayers includes at least one of MgO, (Ba,Sr)TiO 3 , BaHfO 3 , BaZrO 3 , SrHfO 3 , SrZrO 3 , or SrNbO 3 .
14. The electro-optic device of claim 10 , further comprising an epitaxial seed layer between the substrate and the waveguide.
15. The electro-optic device of claim 10 , wherein the substrate comprises silicon or germanium.
16. The electro-optic device of claim 10 , further comprising a pair of electrodes in physical contact and electrical contact with the plurality of electro-optic material layers.
17. The electro-optic device of claim 10 , wherein the plurality of electro-optic material layers are characterized by an in-plane polarization at the cryogenic temperature.
18. The electro-optic device of claim 10 , wherein the plurality of electro-optic material layers may be characterized by a Pockels coefficient greater than 300 pm/V at the cryogenic temperature.
19. The electro-optic device of claim 10 , wherein a ratio between a first thickness of each of the plurality of electro-optic material layers and a second thickness of each of the plurality of interlayers is equal to or less than 20:1.
20. The electro-optic device of claim 10 , wherein a first thickness of each of the plurality of electro-optic material layers is about 100 nm or thinner and a second thickness of each of the plurality of interlayers is about 10 nm or thinner.