Heterogenous Quantum Device Integration: Pick and Place Design and Assembly
Currently, quantum computers in either commercial sector or academic labs are relatively bulky and have large footprints, as computing qubits and detection devices are usually connected through optical fibers or free space optical components. Our research group aims to integrate both through pick and placing nanostructures/cavities that contain diamond solid state qubits onto the target photonic circuit.
Ideally, monolithic integration will be the option to aim for the best device performance, compactness and reduced interconnect complexity, but for our case working with diamond devices, we have to settle with the limitation of current still early-stage diamond-based fabrication technology, and hence, requires heterogenous integration of diamond chip onto the target substrate via pick and place method for intermediate quantum devices.
However, if done correctly, just as the conventional silicon counterpart, heterogeneous integration can benefit from flexibility, customization, faster prototyping, diverse functionality, scalability and interoperability versus monolithic design. Therefore, heterogenous integration technology should be considered as equal and parallel to monolithic design development.
Ref  provides a basic overview of pick and placing microchiplets with single emitters onto target photonic substrate.
In this project, you will integrate state of the art nanostructures, such as diamond chiplet/ cavity/ waveguide and SNSPD (superconducting nanowire single-photon detector), by operating a piezocontrolled pick and place machine that has a step size resolution of tens of nanometer in our lab. Typical tasks are the following:
- Operate pick and place machine to place SNSPD/diamond nanostructures onto the receptor photonic circuit
- Study and optimize pick and place process to achieve higher yield and placement accuracy onto the target substrate
- Design auxiliary support nanostructures for optimizing pick and place process
- Perform photonic simulation that characterize optical coupling efficiency between waveguides
- Measurement of photonic coupling efficiency for the integrated device after pick and place
- Fabricate required nanostructures, such as SiN waveguide arrays for the receptor chip and diamond waveguides/cavities for the donor chip in the cleanroom for pick and place characterization
Multiple students may be admitted to this project.
 Wan, Noel H., et al. "Large-scale integration of artificial atoms in hybrid photonic circuits." Nature 583.7815 (2020): 226-231.