Electro-optical and optoelectronic devices
The present invention is notably directed to an electro-optical device. The latter comprises a layer structure with: a silicon substrate; a buried oxide layer over the silicon substrate; a tapered silicon waveguide core over the buried oxide layer, the silicon waveguide core cladded by a first cladding structure; a bonding layer over the first cladding structure; and a stack of III-V semiconductor gain materials on the bonding layer, the stack of III-V semiconductor gain materials cladded by a second cladding structure. The layer structure is configured to optically couple radiation between the stack of III-V semiconductor gain materials and the tapered silicon waveguide core. The first cladding structure comprises a material having: a refractive index that is larger than 1.54 for said radiation; and a bandgap, which, in energy units, is larger than an average energy of said radiation.
1. An electro-optical device, comprising a layer structure comprising:
a silicon substrate;
a buried oxide layer over the silicon substrate;
a tapered silicon waveguide core over the buried oxide layer, the tapered silicon waveguide core cladded by a first cladding structure, wherein the first cladding structure overlaps a tapered portion of the tapered silicon waveguide core;
a bonding layer over the first cladding structure;
a stack of III-V semiconductor gain materials on the bonding layer, the stack of III-V semiconductor gain materials cladded by a second cladding structure,
wherein:
the layer structure is configured to optically couple radiation between the stack of III-V semiconductor gain materials and the tapered silicon waveguide core; and
the first cladding structure comprises a material, wherein the material is a higher refractive index material, the material having:
a refractive index that is larger than 1.54 for said radiation; and
a bandgap, which, in energy units, is larger than an average energy of said radiation, wherein the first cladding structure further comprises a residual cladding material, wherein the higher refractive index material is laterally embedded in the residual cladding material, wherein the higher refractive index material has a first coplanar interface and a second coplanar interface with the residual cladding material, wherein the first coplanar interface is opposite the second coplanar interface;
wherein a first side of the higher refractive index material directly contacts the bonding layer and a second side of the higher refractive index material directly contacts the tapered silicon waveguide core, wherein the first side is opposite the second side.
2. The electro-optical device according to claim 1 , wherein:
said material of the first cladding structure has a refractive index that is larger than 1.7 for said radiation.
3. The electro-optical device according to claim 1 , wherein:
said material of the first cladding structure has a refractive index that is less than 2.4 for said radiation.
4. The electro-optical device according to claim 1 , wherein:
said material of the first cladding structure comprises one or more of: SiON; Si x N y ; AN; AlO x ; AlON; HfO x ; Ta 2 O 5 ; TiO x ; and ZrO x .
5. The electro-optical device according to claim 1 , wherein:
said material of the first cladding structure is laterally embedded in a medium comprising SiO 2 , said medium covering, at least partly, the buried oxide layer.
6. The electro-optical device according to claim 5 , wherein:
said material of the first cladding structure fills a trench in said medium.
7. The electro-optical device according to claim 1 , wherein:
a minimal distance between a lower layer of said stack of III-V semiconductor gain materials and the tapered silicon waveguide core is between 10 and 1000 nm.
8. The electro-optical device according to claim 7 , wherein:
said minimal distance is between 300 and 800 nm.
9. The electro-optical device according to claim 8 , wherein:
said average thickness of the stack is between 220 nm and 280 nm.
10. The electro-optical device according to claim 7 , wherein:
said minimal distance is between 400 and 600 nm.
11. The electro-optical device according to claim 7 , wherein:
an average thickness of said stack of III-V semiconductor gain materials is between 50 nm and 400 nm.
12. The electro-optical device according to claim 1 , wherein:
said stack of III-V semiconductor gain materials is configured as one of: a laser; an optical detector; and a semiconductor optical amplifier, or SOA.
13. An optoelectronic device comprising:
an integrated circuit, or IC, integrated with the electro-optical device according to claim 1 , as a complementary metal oxide semiconductor integrated circuit, or CMOS IC.
14. The optoelectronic device according to claim 13 , wherein:
said integrated circuit is integrated with said electro-optical device on said silicon substrate.
15. The optoelectronic device according to claim 13 , wherein:
said optoelectronic device is a BiCMOS device and said integrated circuit comprises a heterostructure bipolar transistor.
16. The optoelectronic device according to claim 15 , wherein:
said material of the first cladding structure is laterally embedded in a medium comprising SiO 2 , said medium covering, at least partly, the buried oxide layer; and
said heterostructure bipolar transistor comprises: a silicon collector; a silicon germanium base; and a silicon emitter, each embedded in said medium.