Photonics chip structures including an edge coupler and a layer exhibiting an electric-field-induced Pockels effect
Photonics chip structures including an edge coupler and a layer that exhibits an electric-field-induced Pockels effect and methods of forming such structures. The structure comprises a substrate, an edge coupler on the substrate, and a layer including a portion that has an overlapping relationship with the edge coupler. The layer comprises a material that exhibits an electric-field-induced Pockels effect.
1 . A structure for a photonics chip, the structure comprising:
a first substrate;
a first edge coupler on the first substrate;
a second edge coupler on the first substrate;
a modulator disposed between the first edge coupler and the second edge coupler, the modulator including a first electrode, a second electrode, a third electrode, a first arm including a portion laterally between the first electrode and the second electrode, and a second arm including a portion laterally between the first electrode and the third electrode;
a layer including a first portion that has an overlapping relationship with the first edge coupler and a second portion that has an overlapping relationship with the second edge coupler, the layer comprising a material that exhibits an electric-field-induced Pockels effect; and
a first dielectric layer including a portion between the modulator and the layer, the portion of the first dielectric layer adjoining the layer along a bonding interface,
wherein the first electrode, the second electrode, and the third electrode are disposed between the layer and the bonding interface.
2 . The structure of claim 1 wherein the first edge coupler includes a first facet, the second edge coupler includes a second facet, and the layer has a first side edge that is substantially coterminous with the first facet and a second side edge that is substantially coterminous with the second facet.
3 . The structure of claim 1 wherein the first edge coupler includes a first facet, the second edge coupler includes a second facet, and the layer has a first side edge that is coterminous with the first facet and a second side edge that is coterminous with the second facet.
4 . The structure of claim 1 further comprising:
a light source configured to supply light to the first edge coupler.
5 . The structure of claim 4 further comprising:
an optical fiber configured to receive the light from the second edge coupler.
6 . The structure of claim 1 wherein the material is lithium niobate.
7 . The structure of claim 6 wherein the lithium niobate has a thickness in a range of 300 nanometers to 900 nanometers.
8 . The structure of claim 1 wherein the material is a III-V compound semiconductor.
9 . The structure of claim 1 wherein the material is lithium tantalate, lithium niobate doped with magnesium oxide, or barium titanate.
10 . The structure of claim 1 wherein the material is crystalline and lacks inversion symmetry.
11 . The structure of claim 1 wherein the first edge coupler includes a first facet, and the layer has a first side edge that is substantially coterminous with the first facet.
12 . The structure of claim 11 wherein the second edge coupler includes a second facet, and the layer has a second side edge that is substantially coterminous with the second facet.
13 . The structure of claim 1 wherein the first edge coupler includes a first facet, and the layer has a first side edge that is coterminous with the first facet.
14 . The structure of claim 13 wherein the second edge coupler includes a second facet, and the layer has a second side edge that is coterminous with the second facet.
15 . The structure of claim 1 further comprising:
a second substrate; and
a second dielectric layer on the second substrate, wherein the layer is disposed on the second dielectric layer.
16 . The structure of claim 1 wherein the material has a refractive index that varies in proportional to an applied electric field strength according to an electro-optic coefficient.
17 . A method of forming a structure for a photonics chip, the method comprising:
forming a first edge coupler and a second edge coupler on a first substrate;
forming a modulator disposed between the first edge coupler and the second edge coupler, wherein the modulator includes a first electrode, a second electrode, a third electrode, a first arm including a portion laterally between the first electrode and the second electrode, and a second arm including a portion laterally between the first electrode and the third electrode; and
forming a layer that includes a first portion that has an overlapping relationship with the first edge coupler and a second portion that has an overlapping relationship with the second edge coupler, wherein the layer comprises a material that exhibits an electric-field-induced Pockels effect,
wherein a dielectric layer includes a portion between the modulator and the layer, the portion of the dielectric layer adjoins the layer along a bonding interface, and the first electrode, the second electrode, and the third electrode are disposed between the layer and the bonding interface.
18 . The method of claim 17 further comprising:
bonding the portion of the dielectric layer to the layer along the bonding interface by dielectric bonding or hybrid bonding.
19 . The method of claim 17 further comprising:
placing the layer in a contacting relationship with the portion of the dielectric layer; and
performing a thermal anneal to create a face-to-face bond along the bonding interface.
20 . The method of claim 17 wherein the material is lithium niobate, and the lithium niobate has a thickness in a range of 300 nanometers to 900 nanometers.