Undercut design with a bonded base cover for friendly assembly and effective thermal tuning of micro-ring resonator (MRR) in open cavity photonic integrated chips (OCPIC)
Embodiments disclosed herein include optoelectronic systems and methods of forming such systems. In an embodiment, an optoelectronic system comprises a first substrate, a second substrate over the first substrate, a micro-ring resonator (MRR) over the second substrate, a heater integrated into the MRR, a cladding over the MRR, an opening through the first substrate and the second substrate to expose a bottom surface of the MRR, and a base spanning across the opening.
1. An optoelectronic system, comprising:
a first substrate;
a second substrate over the first substrate;
a micro-ring resonator (MRR) over the second substrate;
a heater integrated into the MRR;
a cladding over the MRR;
an opening through the first substrate and the second substrate to expose a bottom surface of the MRR; and
a base spanning across the opening.
2. The optoelectronic system of claim 1 , wherein the first substrate comprises silicon and the second substrate comprises an oxide.
3. The optoelectronic system of claim 1 , wherein the opening continues into the cladding adjacent to sidewalls of the MRR.
4. The optoelectronic system of claim 3 , wherein the opening continues into the cladding past a top surface of the MRR.
5. The optoelectronic system of claim 1 , wherein the base comprises silicon.
6. The optoelectronic system of claim 1 , wherein the base comprises glass.
7. The optoelectronic system of claim 1 , wherein a thickness of the base is greater than a thickness of the first substrate.
8. The optoelectronic system of claim 1 , wherein the opening through the first substrate has substantially vertical sidewalls.
9. The optoelectronic system of claim 1 , wherein the opening through the first substrate has tapered sidewalls.
10. The optoelectronic system of claim 1 , further comprising:
contacts coupled to a top surface of the MRR.
11. The optoelectronic system of claim 10 , wherein the contacts are electrically coupled to pads on a top surface of the cladding.
12. The optoelectronic system of claim 1 , wherein the MRR has a thickness that is approximately 250 nm or less.
13. A method of forming an optoelectronic system, comprising:
forming a micro-ring resonator (MRR) with a heater on a substrate, wherein the substrate is a silicon on insulator (SOI) substrate with a silicon substrate and an oxide layer over the silicon substrate, and wherein a cladding is provided over and around the MRR;
applying a mask to a bottom surface of the silicon substrate, wherein an opening of the mask is aligned with the MRR;
etching through the silicon substrate and the oxide layer to expose a bottom surface of the MRR; and
attaching a base to the silicon substrate that spans across a hole in the silicon substrate.
14. The method of claim 13 , wherein a width of the opening of the mask is wider than a width of the MRR.
15. The method of claim 14 , wherein the etching further comprises etching the cladding adjacent to the MRR.
16. The method of claim 15 , wherein the etching of the cladding extends past a top surface of the MRR.
17. The method of claim 13 , wherein the base comprises silicon or glass.
18. An optoelectronic system, comprising:
a package substrate;
a photonics integrated circuit (PIC) coupled to the package substrate, wherein the PIC comprises:
a first substrate;
a second substrate over the first substrate;
a micro-ring resonator (MRR) over the second substrate;
a heater integrated into the MRR;
a cladding over the MRR;
an opening through the first substrate and the second substrate to expose a bottom surface of the MRR; and
a base spanning across the opening; and
an electronic integrated circuit (EIC) coupled to the PIC.
19. The optoelectronic system of claim 18 , wherein the base comprises glass.
20. The optoelectronic system of claim 18 , wherein the base comprises silicon.