Quantum Nanophotonics with Lithium Niobate
Abstract
Photonic quantum computing (PQC) has recently emerged as a promising alternative to trapped ion/atom and superconducting qubit based quantum computing technologies. While less mature, PQC offer several exciting opportunities, including room temperature operation (unless superconducting detectors are integrated on the same chip), and large information bandwidth that allows for frequency domain multiplexing and realization of complex quantum states (e.g. cluster states). The most popular and developed integrated PQC platform is based on path-entangled schemes, where the quantum information is imprinted in different waveguide modes. Unfortunately, scaling this approach up to large quantum states is difficult even with the most advanced integrated photonic technology, due to the large size and complexity of photonic circuits needed. To move to a more scalable integrated quantum approach, it is required to change to a different degree of freedom of light. It has recently been shown that the time- and frequency domains of photons are ideal candidates for large-scale quantum optics. Both approaches leverage the wide bandwidth of optical photons that allows multiple qubits to be encoded in the same spatial mode (e.g. the same waveguide mode) but using different frequency or time bins. Frequency PQC can be implemented using a network consisting of simple elements: i) single photon sources, ii) phase shifters, iii) spectral beam splitters, and iv) photon counters. Furthermore, spectral demultiplexers (e.g. filter banks or wavelength selective switches) are required to separate different frequencies and perform measurements on the qubit. In the course of the proposed program we will leverage recent advances in integrated lithium niobate (LN) photonics, pioneered by the PI, to build the main components needed for the realization of a quantum frequency processor (QFP) including: frequency multiplexed single photon source; frequency shifter and frequency beam splitter, implemented using novel photonic molecule concept, and its application as a single-qubit gate; frequency demultiplexer/ wavelength selective switch, leveraging our work on add-drop filters developed for frequency comb applications; We will also demonstrate integration of two or more of these components on the same chip, and evaluate our integrated photonics approach against the state of the art in PQC - approach based on discrete components.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 09, 2020
- Source ID
- W911NF2010248
Entities
People
- Marko Loncar
Organizations
- Army Contracting Command
- Defense Advanced Research Projects Agency
- Harvard University