Twin beams and squeezing via optical fiber instabilities

Martin A. Finger, T. Sh. Iskhakov, Nicolas Y. Joly +2 more

We report a novel source of twin beams based on modulational instability in high-pressure argon-filled hollow-core kagome-style photonic-crystal fiber. The source is Raman-free and manifests strong photon-number correlations for femtosecond pulses of squeezed vacuum with a record brightness of ∼2500 photons per mode. The ultra-broadband (∼50 THz) twin beams are frequency tunable and contain one spatial and less than 5 frequency modes. The presented source outperforms all previously reported squeezed-vacuum twin-beam sources in terms of brightness and low mode content.

Claude Fabre, E. Giacobino, Serge Reynaud +3 more

T. A. B. Kennedy

We consider the quantum correlations between fields generated through cross-phase-modulational instability in an optical fiber. Two examples of this instability are addressed, one relating to the linear-polarization eigenstates in a high-birefringence fiber, and the other to two-color propagation in a fiber. The degrees of second-order coherence of the quantum noise sidebands generated in this ${\mathrm{\ensuremath{\chi}}}^{(3)}$ process are calculated, and the violation of a classical Cauchy-Schwarz inequality and intensity-difference squeezing is reported for light transmitted by a passive filter. Around 50% intensity-difference squeezing is possible in the case of the two-color instability. This illustrates the quantum-statistical nature of the sideband correlations and how passive processing may in some circumstances help accentuate quantum correlations.

Christopher Richard Doerr, Ilya Lyubomirsky, Gadi Lenz +3 more

Hong-Yi Yan, Wen Zhen Zhao, Xueshi Guo +1 more

We demonstrate an adaptive electrical gain optimized detection scheme for pulsed twin beams in optical fiber. Intensity difference squeezing level of -7.5 dB has been measured without the need of accurately calibrating channel losses.

P. D. Drummond