Generation of highly pure single-photon state at telecommunication wavelength

Abstract

Telecommunication wavelength with well-developed optical communication technologies and low losses in the waveguide are advantageous for quantum applications. However, an experimental generation of non-classical states called non-Gaussian states at the telecommunication wavelength is still underdeveloped. Here, we generate highly-pure-single-photon states, one of the most primitive non-Gaussian states, by using a heralding scheme with an optical parametric oscillator and a superconducting nano-strip photon detector. The Wigner negativity, the indicator of non-classicality, of the generated single photon state is -0.228 ± 0.004, corresponded to 85.1 ± 0.7% of single photon and the best record of the minimum value at all wavelengths. The quantum-optics-technology we establish can be easily applied to the generation of various types of quantum states, opening up the possibility of continuous-variable-quantum-information processing at the telecommunication wavelength.

Non-Gaussian quantum state generation by multi-photon subtraction at the telecommunication wavelength

“…The propagation loss of 5% is mainly due to variable beam splitters consisting HWPs and PBSs for tapping and the HD. If these were replaced with fixed-ratio beamsplitters of high quality, the propagation loss could be reduced to 3% [30].…”

“…Recent advances in superconducting photon detectors at telecommunication wavelengths [25][26][27][28][29] have enabled the observation of non-Gaussian states with Wigner negativity in the continuous-wave (cw) regime [30,31]. Additionally, wavelength conversion methods have been used to generate non-Gaussian states [32].…”

Acousto-optic modulator-based bi-frequency interferometer for quantum technology

“…However, in this scheme, both the isolation and the transmission efficiency of the switch are confined by the visibility of the interference. In quantum technologies, AOM-based switches are often used as a protection stage before a weak light detection process [7,9] , and good isolation is a critical requirement for such a switch. To solve this problem, we propose the optical switch scheme in Fig.…”

“…In addition to the aforementioned applications in classical technology, AOMs are also indispensable for many quantum technologies. Taking advantage of switching with high isolation, they have been used in photon subtraction-based non-Gaussian state generation [7,8] , photon-triggered homodyne tomography [9] , or controlling of quantum memory [10] . Taking advantage of introducing frequency shifting to an optical field, they are used to implement optical heterodyning [11,12] , to observe a beating signal from single photons [13] , or to generate a phase-locking reference without displacing the quantum state [14] .…”