Optical cladding layer design
Embodiments of the invention describe apparatuses, optical systems, and methods related to utilizing optical cladding layers. According to one embodiment, a hybrid optical device includes a silicon semiconductor layer and a III-V semiconductor layer having an overlapping region, wherein a majority of a field of an optical mode in the overlapping region is to be contained in the III-V semiconductor layer. A cladding region between the silicon semiconductor layer and the III-V semiconductor layer has a spatial property to substantially confine the optical mode to the III-V semiconductor layer and enable heat dissipation through the silicon semiconductor layer.
1. An apparatus, comprising:
a silicon semiconductor layer defining a longitudinal direction perpendicular to a top surface of the silicon semiconductor layer and a lateral direction parallel to the silicon semiconductor layer, the silicon semiconductor layer having a first thickness in a first lateral region and a second thickness in a second lateral region, the second thickness being less than the first thickness;
a cladding layer positioned on the silicon semiconductor layer, the cladding layer having a third thickness in a third lateral region, the third lateral region positioned longitudinally adjacent to the first lateral region, the cladding layer having a fourth thickness in a fourth lateral region, the fourth lateral region positioned longitudinally adjacent to the second lateral region, the fourth thickness being greater than the third thickness; and
a III-V semiconductor layer positioned on the cladding layer, the III-V semiconductor layer having a refractive index greater than a refractive index of the cladding layer, the III-V semiconductor layer having a fifth thickness in a fifth lateral region, at least a portion of the fifth lateral region being longitudinally adjacent to at least a portion of the third lateral region, the III-V semiconductor layer having a sixth thickness in a sixth lateral region, the sixth thickness being greater than the fifth thickness, at least a portion of the sixth lateral region being longitudinally adjacent to at least a portion of the fourth lateral region.
2. The apparatus of claim 1 , wherein the first, second, third, fourth, fifth, and sixth lateral regions are shaped to form a waveguide for at least a first wavelength of light.
3. The apparatus of claim 2 , wherein the first, second, third, and fourth lateral regions are shaped to form a thermal shunt of silicon extending into the cladding layer.
4. The apparatus of claim 3 , wherein the thermal shunt has dimensions smaller than the first wavelength of light in the silicon semiconductor layer.
5. The apparatus of claim 2 , wherein the first, second, third, and fourth lateral regions are shaped to form a plurality of thermal shunts of silicon extending into the cladding layer.
6. The apparatus of claim 5 , wherein each thermal shunt has dimensions smaller than the first wavelength of light in the silicon semiconductor layer.
7. The apparatus of claim 1 , wherein the III-V semiconductor layer extends laterally beyond the first, second, third, and fourth lateral regions.
8. The apparatus of claim 1 , wherein a sum of the second and fourth thicknesses equals a sum of the first and third thicknesses.
9. The apparatus of claim 1 , wherein the cladding layer has a thermal conductivity less than a thermal conductivity of silicon.
10. The apparatus of claim 1 , wherein the cladding layer includes a dielectric material.
11. The apparatus of claim 1 , wherein the cladding layer includes a polymer.
12. An apparatus, comprising:
a silicon semiconductor layer defining a longitudinal direction perpendicular to a top surface of the silicon semiconductor layer and a lateral direction parallel to the silicon semiconductor layer, the silicon semiconductor layer having a first thickness in a first lateral region and a second thickness in a second lateral region, the second thickness being less than the first thickness;
a cladding layer positioned on the silicon semiconductor layer, the cladding layer having a third thickness in a third lateral region, the third lateral region positioned longitudinally adjacent to the first lateral region, the cladding layer having a fourth thickness in a fourth lateral region, the fourth lateral region positioned longitudinally adjacent to the second lateral region, the fourth thickness being greater than the third thickness, the cladding layer having a thermal conductivity less than a thermal conductivity of silicon, wherein the first, second, third, and fourth lateral regions are shaped to form at least one thermal shunt of silicon extending into the cladding layer; and
a III-V semiconductor layer positioned on the cladding layer, the III-V semiconductor layer having a refractive index greater than a refractive index of the cladding layer, the III-V semiconductor layer having a fifth thickness in a fifth lateral region, at least a portion of the fifth lateral region being longitudinally adjacent to at least a portion of the third lateral region, the III-V semiconductor layer having a sixth thickness in a sixth lateral region, the sixth thickness being greater than the fifth thickness, at least a portion of the sixth lateral region being longitudinally adjacent to at least a portion of the fourth lateral region.
13. The apparatus of claim 12 , wherein:
the first, second, third, fourth, fifth, and sixth lateral regions are shaped to form a waveguide for at least a first wavelength of light; and
each thermal shunt has dimensions smaller than the first wavelength of light in the silicon semiconductor layer.