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Springer eBooks

Source of photon-number-squeezed light with adjustable level of squeezing

Ondřej Haderka, Jan Peřina, Jan Soubusta

Published Jan 1, 2003• 0 citations
Publisher
DOI
10.1007/978-1-4419-8907-9_138

Related papers

Generation of Squeezed Light

E. Giacobino

Springer proceedings in physics•Jan 1, 1991•0 citations

Generation of a coherent squeezed-like state defined with the Lie–Trotter product formula using a nonlinear photonic crystal

Hiroo Azuma

Abstract In this paper, we investigate how to generate coherent squeezed-like light using a nonlinear photonic crystal. Because the photonic crystal reduces the group velocity of the incident light, if it is composed of a material with a second-order nonlinear optical susceptibility χ ( 2 ) , the interaction between the nonlinear material and the light passing through it strengthens and the quantum state of the emitted light is largely squeezed. Thus, we can generate a coherent squeezed-like light with a resonating cavity in which the nonlinear photonic crystal is placed. This coherent squeezed-like state is defined with the Lie–Trotter product formula and its mathematical expression is different from those of conventional coherent squeezed states. We show that we can obtain this coherent squeezed-like state with a squeezing level 15.9 dB practically by adjusting the physical parameters for our proposed method. Feeding the squeezed light whose average number of photons is given by one or two into a beam splitter and splitting the flow of the squeezed light into a pair of entangled light beams, we estimate their entanglement quantitatively. This paper is a sequel to Azuma (2022 J. Phys. D: Appl. Phys. 55 315106).

arXiv:2304.11373•Journal of Physics D Applied Physics•Aug 14, 2023•0 citations

Photon number squeezing with a noisy fiber amplifier source by balanced detection technique

Shota Sawai, Hikaru Kawauchi, Kenichi Hirosawa +1 more

Summary form only given. Squeezed light at telecommunication wavelength is important source in the field of quantum information and communication technology, especially for realization of entanglement state with continuous variables. However, erbium-doped fiber amplifier (EDFA) used in classical communication systems contains substantially high intensity noise which is much higher than the shot noise level (SNL) due to beat noise of amplified spontaneous emission. Therefore, alternatively, optical parametric oscillators and Cr:YAG lasers have been employed for generation of squeezed light. In this work, we achieved photon number squeezing at 1.55 μm using a noisy EDFA laser as a light source, making use of collinear balanced detection technique, demonstrated by Nose et al.[1]. This technique compensates intensity noise at a specific radio-frequency by means of pulse splitting and recombination with a relative time delay τ. The photocurrent contributed by pulse trains is given by I(t) = I1(t) + I2(t) = I1(t) + I1(t-τ), where I1(t) and I2(t) is the photocurrent contributed by the first and second pules, respectively. The equation does not contain an interference term because any pulse does not temporally overlap each other. In the Fourier domain,we can obtain I(ω) = I1(ω) + I2(ω) = I1(ω) + I1(ω)exp(iωτ) and confirm the photocurrents are added up destructively at ω = π/τ. In our experiment, laser pulses, of which intensity noise is higher than 10dB from SNL, were divided into two parts and each of them experienced self-phase modulation during propagation through two different single-mode optical fibers. We detected the two pulse trains with a relative time delay and observed photon number squeezing a specific frequency. We used a femtosecond fiber laser (Femtolite, IMRA) as a light source. The center wavelength was 1560 nm and the repetition rate was 47.5 MHz. Figure 1 shows the experimental setup. We added time delay τ=1/frep, where frep is the repetition frequency, to one of the two pulse trains and added another delay deltaτ for preventing optical interference. We confirmed that intensity noise of the two pulse trains colineared at a polarization beam splitter (PBS) was coincident to the SNL both before and after fiber propagation at 22MHz. SNL was measured by balanced homodyne detection. We employed nonlinear polarization interferometer to generate squeezed light[2]. For measuring photon number squeezing, a branch ratio at PBS1 and PBS3,4 was adjusted to 90:10 and 95:5, respectively. We constructed another Michelson interferometer after a beam splitter to compensate the difference of fiber length. As a result, a maximum photon-number squeezing of 2.6 dB was obtained when average power was 4mW.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•May 1, 2013•0 citations

Theory of Squeezed Light Generation

M. D. Reid, Alistair S. Lane, Daniel F. Walls

Springer proceedings in physics•Jan 1, 1986•4 citations

Generation and Application of Squeezed States of Light

Harry J. Kimble, Robert J. Brecha, Luis A. Orozco +3 more

Springer series in optical sciences/SPringer series in optical sciences•Jan 1, 1987•1 citation

Generation of 1.5 µm Squeezed Vacuum Pulse Using a Sagnac Loop Interferometer

Kenichi Hirosawa, Yoshinori Momose, Yuji FUJIWARA +4 more

Photon-number squeezing and quadrature squeezing were studied using ultrafast fibre nonlinear optics pumped by 1.5 µm femtosecond laser pulses. To obtain quadrature squeezing using an Erbium doped fibre amplifiers (EDFA) light source, we developed temporal homodyne technology to exclude the excess noise of an EDFA light source. We also performed a quadrature squeezing experiment using an optical parametric oscillator light source in stead of an EDFA light source exhibiting substantially high excess noise. Although the photon-number squeezing of -3dB was obtained from an asymmetric Sagnac fibre loop, the quadrature noise could not decrease to less than the Shot noise level without cooling the fibre, which is presumably due to GAWBS. To suppress guided acoustic wave Brillouin scattering, we refrigerated the fibre loop by liquid nitrogen, and squeezing at -0.7 dB was obtained by cooling the fiber at liquid nitrogen temperature.

The Review of Laser Engineering•Jan 1, 2008•0 citations
Abstract In this paper, we investigate how to generate coherent squeezed-like light using a nonlinear photonic crystal. Because the photonic crystal reduces the group velocity of the incident light, if it is composed of a material with a second-order nonlinear optical susceptibility χ ( 2 ) , the interaction between the nonlinear material and the light passing through it strengthens and the quantum state of the emitted light is largely squeezed. Thus, we can generate a coherent squeezed-like light with a resonating cavity in which the nonlinear photonic crystal is placed. This coherent squeezed-like state is defined with the Lie–Trotter product formula and its mathematical expression is different from those of conventional coherent squeezed states. We show that we can obtain this coherent squeezed-like state with a squeezing level 15.9 dB practically by adjusting the physical parameters for our proposed method. Feeding the squeezed light whose average number of photons is given by one or two into a beam splitter and splitting the flow of the squeezed light into a pair of entangled light beams, we estimate their entanglement quantitatively. This paper is a sequel to Azuma (2022 J. Phys. D: Appl. Phys. 55 315106).
Summary form only given. Squeezed light at telecommunication wavelength is important source in the field of quantum information and communication technology, especially for realization of entanglement state with continuous variables. However, erbium-doped fiber amplifier (EDFA) used in classical communication systems contains substantially high intensity noise which is much higher than the shot noise level (SNL) due to beat noise of amplified spontaneous emission. Therefore, alternatively, optical parametric oscillators and Cr:YAG lasers have been employed for generation of squeezed light. In this work, we achieved photon number squeezing at 1.55 μm using a noisy EDFA laser as a light source, making use of collinear balanced detection technique, demonstrated by Nose et al.[1]. This technique compensates intensity noise at a specific radio-frequency by means of pulse splitting and recombination with a relative time delay τ. The photocurrent contributed by pulse trains is given by I(t) = I1(t) + I2(t) = I1(t) + I1(t-τ), where I1(t) and I2(t) is the photocurrent contributed by the first and second pules, respectively. The equation does not contain an interference term because any pulse does not temporally overlap each other. In the Fourier domain,we can obtain I(ω) = I1(ω) + I2(ω) = I1(ω) + I1(ω)exp(iωτ) and confirm the photocurrents are added up destructively at ω = π/τ. In our experiment, laser pulses, of which intensity noise is higher than 10dB from SNL, were divided into two parts and each of them experienced self-phase modulation during propagation through two different single-mode optical fibers. We detected the two pulse trains with a relative time delay and observed photon number squeezing a specific frequency. We used a femtosecond fiber laser (Femtolite, IMRA) as a light source. The center wavelength was 1560 nm and the repetition rate was 47.5 MHz. Figure 1 shows the experimental setup. We added time delay τ=1/frep, where frep is the repetition frequency, to one of the two pulse trains and added another delay deltaτ for preventing optical interference. We confirmed that intensity noise of the two pulse trains colineared at a polarization beam splitter (PBS) was coincident to the SNL both before and after fiber propagation at 22MHz. SNL was measured by balanced homodyne detection. We employed nonlinear polarization interferometer to generate squeezed light[2]. For measuring photon number squeezing, a branch ratio at PBS1 and PBS3,4 was adjusted to 90:10 and 95:5, respectively. We constructed another Michelson interferometer after a beam splitter to compensate the difference of fiber length. As a result, a maximum photon-number squeezing of 2.6 dB was obtained when average power was 4mW.
Photon-number squeezing and quadrature squeezing were studied using ultrafast fibre nonlinear optics pumped by 1.5 µm femtosecond laser pulses. To obtain quadrature squeezing using an Erbium doped fibre amplifiers (EDFA) light source, we developed temporal homodyne technology to exclude the excess noise of an EDFA light source. We also performed a quadrature squeezing experiment using an optical parametric oscillator light source in stead of an EDFA light source exhibiting substantially high excess noise. Although the photon-number squeezing of -3dB was obtained from an asymmetric Sagnac fibre loop, the quadrature noise could not decrease to less than the Shot noise level without cooling the fibre, which is presumably due to GAWBS. To suppress guided acoustic wave Brillouin scattering, we refrigerated the fibre loop by liquid nitrogen, and squeezing at -0.7 dB was obtained by cooling the fiber at liquid nitrogen temperature.