No Arabic abstract
High-flux entangled photon source is the key resource for quantum optical study and application. Here it is realized in a lithium niobate on isolator (LNOI) chip, with 2.79*10^11 Hz/mW photon pair rate and 1.53*10^9 Hz/nm/mW spectral brightness. These data are boosted by over two orders of magnitude compared to existing technologies. A 130-nm broad bandwidth is engineered for 8-channel multiplexed energy-time entanglement. Harnessed by high-extinction frequency correlation and Franson interferences up to 99.17% visibility, such energy-time entanglement multiplexing further enhances high-flux data rate, and warrants broad applications in quantum information processing on a chip.
Integrated quantum optics becomes a consequent tendency towards practical quantum information processing. Here, we report the on-chip generation and manipulation of photonic entanglement based on reconfigurable lithium niobate waveguide circuits. By introducing periodically poled structure into the waveguide interferometer, two individual photon-pair sources with controllable phase-shift are produced and cascaded by a quantum interference, resulting in a deterministically separated identical photon pair. The state is characterized by 92.9% visibility Hong-Ou-Mandel interference. Continuous morphing from two-photon separated state to bunched state is further demonstrated by on-chip control of electro-optic phase-shift. The photon flux reaches ~1.4*10^7 pairs nm-1 mW-1. Our work presents a scenario for on-chip engineering of different photon sources and paves a way to the fully integrated quantum technologies.
We report an on-chip single mode microlaser with low-threshold fabricated on Erbium doped lithium niobate on insulator (LNOI). The single mode laser emission at 1550.5 nm wavelength is generated in a coupled photonic molecule, which is facilitated by Vernier effect when pumping the photonic molecule at 970 nm. A threshold pump power as low as 200 uW is demonstrated thanks to the high quality factor above 10^6. Moreover, the linewidth of the microlaser reaches 4 kHz, which is the best result in LNOI microlasers. Such single mode micro-laser lithographically fabricated on chip is highly in demand by photonic community.
The ultimate goal of quantum information science is to build a global quantum network, which enables quantum resources to be distributed and shared between remote parties. Such quantum network can be realized by all fiber elements, which takes advantage of low transmission loss,low cost, scalable and mutual fiber communication techniques such as dense wavelength division multiplexing. Therefore high quality entangled photon sources based on fibers are on demanding for building up such kind of quantum network. Here we report multiplexed polarization and timebin entanglement photon sources based on dispersion shifted fiber operating at room temperature. High qualities of entanglement are characterized by using interference, Bell inequality and quantum state tomography. Simultaneous presence of entanglements in multichannel pairs of a 100GHz DWDM shows the great capacity for entanglements distribution over multi-users. Our research provides a versatile platform and moves a first step toward constructing an all fiber quantum network.
Using the process of spontaneous parametric down conversion in a novel two-crystal geometry, one can generate a source of polarization-entangled photon pairs which is orders of magnitude brighter than previous sources. We have measured a high level of entanglement between photons emitted over a relatively large collection angle, and over a 10-nm bandwidth. As a demonstration of the source intensity, we obtained a 242-$sigma$ violation of Bells inequalities in less than three minutes.
We demonstrate waveguide-integrated superconducting nanowire single-photon detectors on thin-film lithium niobate (LN). Using a 250 um-long NbN superconducting nanowire lithographically defined on top of a 125 um-long LN nanowaveguide, on-chip detection efficiency of 46% is realized with simultaneous high performance in dark count rate and timing jitter. As LN possesses high second-order nonlinear c{hi}(2) and electro-optic properties, an efficient single-photon detector on thin-film LN opens up the possibility to construct small scale fully-integrated quantum photonic chip which includes single-photon sources, filters, tunable quantum gates and detectors.