Photonic communication platform
Described herein are photonic communication platforms that can overcome the memory bottleneck problem, thereby enabling scaling of memory capacity and bandwidth well beyond what is possible with conventional computing systems. Some embodiments provide photonic communication platforms that involve use of photonic modules. Each photonic module includes programmable photonic circuits for placing the module in optical communication with other modules based on the needs of a particular application. The architecture developed by the inventors relies on the use of common photomask sets (or at least one common photomask) to fabricate multiple photonic modules in a single wafer. Photonic modules in multiple wafers can be linked together into a communication platform using optical or electronic means.
1 . A method for fabricating a photonic system, comprising:
using a stepper machine to lithographically pattern a semiconductor wafer with a plurality of photonic modules, wherein patterning the semiconductor wafer comprises:
forming a first photonic module by patterning a first area of the semiconductor wafer using a first photomask, wherein the first photomask defines optical waveguides;
subsequent to forming the first photonic module, forming a second photonic module by patterning a second area of the semiconductor wafer using the first photomask, wherein the second area of the semiconductor wafer is adjacent to the first area of the semiconductor wafer such that, when formed, the first photonic module and the second photonic module are optically coupled to each other;
doping the first photonic module using a second photomask, wherein the second photomask defines doping regions;
subsequent to doping the first photonic module, doping the second photonic module using the second photomask;
forming a first silicon nitride waveguide in the first photonic module using a third photomask; and
subsequent to forming the first silicon nitride waveguide in the first photonic module, forming a second silicon nitride waveguide in the second photonic module using the third photomask.
2 . The method of claim 1 , further comprising:
forming first metal pads in the first photonic module using a fourth photomask; and
subsequent to forming the first metal pads in the first photonic module, forming second metal pads in the second photonic module using the fourth photomask, wherein the first and second metal pads are sized to bond to electronic chips.
3 . The method of claim 1 , further comprising:
forming first metal traces in the first photonic module using a fourth photomask; and
subsequent to forming the first metal traces in the first photonic module, forming second metal traces in the second photonic module using the fourth photomask.
4 . The method of claim 3 , further comprising:
forming a first germanium region in the first photonic module using a fifth photomask; and
subsequent to forming the first germanium region in the first photonic module, forming a second germanium region in the second photonic module using the fifth photomask.
5 . The method of claim 1 , wherein, when formed, the first photonic module comprises a first waveguide and the second photonic module comprises a second waveguide, wherein the first waveguide is coupled to the second waveguide.
6 . The method of claim 5 , wherein the first waveguide is physically connected to the second waveguide.
7 . The method of claim 5 , wherein the first waveguide is separated from the second waveguide by a gap.
8 . The method of claim 1 , wherein doping the first photonic module comprises p-doping the first photonic module and doping the second photonic module comprises p-doping the second photonic module,
wherein the method further comprises:
n-doping the first photonic module using a fourth photomask, wherein the third photomask defines doping regions; and
subsequent to n-doping the first photonic module, n-doping the second photonic module using the fourth photomask.
9 . The method of claim 1 , wherein, when formed, the plurality of photonic modules are arranged in a two-dimensional scheme.
10 . A method for fabricating a photonic system, comprising:
using a stepper machine to lithographically pattern a semiconductor wafer with a plurality of photonic modules arranged in a two-dimensional scheme, wherein patterning the semiconductor wafer comprises:
forming a first photonic module by patterning a first area of the semiconductor wafer using a first photomask, wherein the first photomask defines optical waveguides;
subsequent to forming the first photonic module, forming a second photonic module by patterning a second area of the semiconductor wafer using the first photomask;
subsequent to forming the second photonic module, forming a third photonic module by patterning a third area of the semiconductor wafer using the first photomask, wherein the first area of the semiconductor wafer is adjacent to both the second and third areas of the semiconductor wafer such that, when formed, the first photonic module is optically coupled to the second photonic module in a first direction and to the third photonic module in a second direction perpendicular to the first direction;
forming a first silicon nitride waveguide in the first photonic module using a second photomask;
subsequent to forming the first silicon nitride waveguide in the first photonic module, forming a second silicon nitride waveguide in the second photonic module using the second photomask; and
subsequent to forming the second silicon nitride waveguide in the second photonic module, forming a third silicon nitride waveguide in the third photonic module using the second photomask.
11 . The method of claim 10 , further comprising:
doping the first photonic module using a third photomask, wherein the second photomask defines doping regions;
subsequent to doping the first photonic module, doping the second photonic module using the third photomask; and
subsequent to doping the second photonic module, doping the third photonic module using the third photomask.
12 . The method of claim 11 , wherein doping the first photonic module comprises p-doping the first photonic module, doping the second photonic module comprises p-doping the second photonic module, and doping the third photonic module comprises p-doping the third photonic module,
wherein the method further comprises:
n-doping the first photonic module using a fourth photomask, wherein the third photomask defines doping regions;
subsequent to n-doping the first photonic module, n-doping the second photonic module using the fourth photomask; and
subsequent to n-doping the second photonic module, n-doping the third photonic module using the fourth photomask.
13 . The method of claim 10 , further comprising:
forming a first germanium region in the first photonic module using a third photomask;
subsequent to forming the first germanium region in the first photonic module, forming a second germanium region in the second photonic module using the third photomask; and
subsequent to forming the second germanium region in the second photonic module, forming a third germanium region in the third photonic module using the third photomask.
14 . The method of claim 10 , wherein, when formed, the first photonic module comprises a first waveguide and the second photonic module comprises a second waveguide, wherein the first waveguide is coupled to the second waveguide.
15 . The method of claim 14 , wherein the first waveguide is physically connected to the second waveguide.
16 . The method of claim 14 , wherein the first waveguide is separated from the second waveguide by a gap.