Squeezing of light in a degenerate parametric amplifier under small detuning of the pumping frequency

Ivan Deutsch, J. C. Garrison

Ivan Deutsch, J. C. Garrison

Alessandro Vaglica, Cristina Leonardi, G. Vetri

Hidenori Koyano, Tomohiko Uyematsu, Norihiro Yoshida +1 more

Abstract In this paper, characteristics of degenerate parametric amplifiers are analyzed and are expected to be useful as a generator of a squeezed state or a noiseless amplifier for an optical wave. Especially, when a degenerate parametric amplifier is used as a noiseless amplifier or a squeezed‐state generator (squeezer), the depletion of the pumping light which has been neglected affects the quantum noise characteristic of the squeezed light. This effect is analyzed in this paper. Further, when the incident light does not satisfy the phase matching condition, the effect of this phase shift on the gain and quantum noise characteristics of the degenerate parametric amplifier is studied. On the other hand, when a degenerate parametric amplifier is used as a preamplifier for the receiving side of the communication system, the phase noise of the pumping light can be a cause of degradation of the communication system performance. The phase noise of the pumping light is classified as the phase shift and the phase fluctuation caused by the quantum noise and then the effects of these phase noises on the quantum noise characteristics of the squeezed light are analyzed. Further, in the BPSK optical coherent communication system, the effect of the phase noise on the bit error rate is analyzed. A quantitative evaluation is made to determine how small the phase noise of the pumping light should be in order not to degrade the error rate.

Lei Yang, Fengwei Sun, Ningbo Zhao +1 more

Using a Sagnac fiber loop functions as a deterministic splitter of photon pairs produced by the frequency degenerate four wave mixing, we show that the background noise of the degenerate photon pairs is contributed by both Raman scattering and frequency non-degenerate four wave mixing. To improve the purity of photon pairs in the high gain regime, in addition to suppressing the noise photons by cooling the nonlinear fiber and by optimizing the detuning between the frequencies of the pump and photon pairs, the walk-off effect of the two pulsed pump fields should be mitigated by managing the dispersion of the fiber. Our investigation is not only the first step towards the generation of multi-mode squeezed vacuum in fiber optical parametric amplifiers pumped with pulsed lights, but also contributes to improving the purity of the fiber sources of degenerate photon pairs.

Aashish A. Clerk, McDonald, Alexander

Optimally detuned parametric amplification amplifies a signal in a resonator that is driven off-resonance, with respect to a signal mode, using a far-detuned pump. This pump establishes a parametric drive strength, and is "far-detuned" in that its detuning from the signal mode is greater than the drive strength. The amplitude and frequency of the pump are chosen so that the eigenfrequency of the resulting Bogoliobov mode matches a photonic loss rate of the Bogoliobov mode. In this case, a signal coupled into the Bogoliobov mode will be amplified with a gain that is broader and flatter than that achieved with conventional parametric amplification, and is not limited by a gain-bandwidth product. Optimally detuned parametric amplification may be used for degenerate or non-degenerate parametric amplification, and may be used to amplify microwaves, light, electronic signals, acoustic waves, or any other type of signal that can be amplified using conventional parametric amplification.