Experimental generation of broadband quadrature entanglement using laser pulses

30 years of squeezed light generation

“…By confining the pump field in the nonlinear crystal over a long distance by means of a crystalline waveguide structure (thereby circumventing diverging beams due to diffraction), it is possible to increase the effective nonlinearity even further. Using such systems single-pass pulsed squeezing [48][49][50] and even single-pass continuous wave squeezing has been observed [51,52].…”

An all-fiber source of pulsed twin beams for quantum communication

“…Another approach to enhancing the nonlinearity is to use pulsed lasers as the pump for an OPA due to the available high peak power. 11,12 Experimental systems based on the pulse pumped single-pass OPA are usually simpler than those with cavities but the measured levels of quantum-noise reduction fall short of those in CW cases, particularly for the case of ultrashort pump pulses 7,8,[12][13][14] due to a lack of understanding about spectral properties of the systems. 15 Recently, four-wave mixing (FWM) based on the v ð3Þ nonlinearity in atoms or fibers was used to generate nonclassical light as well.…”

“…This is the highest quantum noise reduction obtained in a FOPA. Moreover, instead of pumping the FOPA with an expensive bulk mode-locked laser, which is used for generating the pulsed CV quantum states in previous experiments, 8,9,12,14 our FOPA is pumped by a mode-locked fiber laser. Therefore, our all-fiber source of pulsed twin beams is compact and robust.…”

Controlling quantum interference in phase space with amplitude

“…To realize this control, a variable attenuator, which consists of a half-wave plate (HWP) and a polarizing beam-splitter (PBS) was inserted in the arm of the control light. The effective squeezing parameter r was estimated to be 0.15 from the measured parametric gain with different pump powers by taking into account the mode matching efficiency between the pump light and the control light 33, 34 . A minimum deamplification of −0.6 dB and maximum amplification of 0.8 dB were obtained at the provided pump power of about 30 mW.…”