Generation of 8.3 dB continuous variable quantum entanglement at a telecommunication wavelength of 1550 nm

Abstract

Continuous variable quantum entanglement at a telecommunication wavelength of 1550 nm is experimentally generated using a single nondegenerate optical parametric amplifier based on a type-II periodically poled KTiOPO 4 crystal. The triply resonant of the nondegenerate optical parametric amplifier is adjusted by tuning the crystal temperature and tilting the orientation of the crystal in the optical cavity. Einstein-Podolsky-Rosen-entangled beams with quantum correlations of 8.3 dB for both the amplitude and phase quadratures are experimentally generated. This system can be used for continuous variable fibre-based quantum communication.

Production and applications of non-Gaussian quantum states of light

“…The highest squeezing levels have so far been observed using OPAs in the continuous-wave (cw) regime: 15 dB for single-mode squeezing 8.3-8.4 dB for two-mode squeezing (Jinxia et al, 2018;Zhou et al, 2015). Optical powers available in this regime are too low to obtain significant parametric gains in a single pass through a non-linear crystal.…”

Novel continuous-variable quantum secure direct communication and its security analysis

“…The continuous-variable (CV) regime in contrast is more attractive given that it can be well compatible with fully developed optical telecommunication technologies. In particular, the realization of CV quantum entanglement, which can be adopted for CV fiber-based quantum communication, helps the development of CV-based QSDC [25]. It is essential to combine QSDC with the CV regime to accomplish the communication task with lower implementation costs.…”

Improvement of the entanglement properties for entangled states using a superposition of number-conserving operations

“…However, due to the low detection efficiency and the high cost, there are some limitations in the preparation and manipulation of the DV-based entangled state [7]. In order to overcome the above limitations, the entangled state in continuous-variable (CV) systems has been of great concern in recent years [8][9][10][11]. In particular, a Gaussian entangled state is usually treated as an important entanglement source in the successful implementations of quantum cryptography [12,13], quantum metrology [14][15][16] and quantum repeaters [17,18].…”