Correlations on a chip

Peyman Sarrafi, Eric Y. Zhu, Ksenia Dolgaleva +4 more

We report on the demonstration of correlated photon pair generation in a quasi-phase-matched superlattice GaAs/AlGaAs waveguide using a continuous-wave pump. Our photon pair source has a low noise level and achieves a high coincidence-to-accidental ratio greater than 100, which is the highest value reported in III–V chips so far. This correlated photon pair source has the potential to be monolithically integrated with on-chip pump laser sources fabricated on the same superlattice wafer structure, enabling direct correlated/entangled photon pair production from a compact electrically powered chip.

M. Bönitz

Anonymous

Przybyz, J. X., Miller, D. L., Lavoie, Chris +1 more

The contract for Battlefield Online with Superconductive Systems build upon the success of previous AFRL contracts to develop components based on superconductive electronics for spread spectrum modems. The prior work had demonstrated a low power chip that operated at 2 GHz and performed spread spectrum functions. This contract developed a Digital Correlator and a rapid Synchronizer and demonstrated that the correlation and synchronization could be performed with superconductive digital electronics. The Digital Correlator demonstrated correct mixing of 2-bit Data with Code and accumulation of the correlation sum at speeds up to 320 MHz. It correctly accumulated single inputs at rates up to 3 GHz. The synchronizer demonstrated most of its functions at low speed. Another task supported the design of a Glue Chip for use in a Crossbar data switch. The Glue Chip is part of a multichip module that forms the switch fabric. The Glue Chip was designed to have high sensitivity to weal signals, but changes in the design of the Switch Chip created a stronger signal, so the sensitive Glue Chips were not built. The high-speed circuits developed under these AFRL contracts have the ability to transform communications. The report contains two scientific papers: "Spread Spectrum Data Transfer from Dewar to Dewar at 2 Gigachips per Second," and "Digital Correlator for a Spread Spectrum Modem Operating at 2 Gigachips per Second."

Davide Grassani, Angelica Simbula, Mihir Pant +7 more

We demonstrate the generation of quantum-correlated photon pairs combined with the spectral filtering of the pump field by more than 95 dB on a single silicon chip using electrically tunable ring resonators and passive Bragg reflectors. Moreover, we perform the demultiplexing and routing of signal and idler photons after transferring them via an optical fiber to a second identical chip. Nonclassical two-photon temporal correlations with a coincidence-to-accidental ratio of 50 are measured without further off-chip filtering. Our system, fabricated with high yield and reproducibility in a CMOS-compatible process, paves the way toward large-scale quantum photonic circuits by allowing sources and detectors of single photons to be integrated on the same chip.

Christof Wetterich