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arXiv · 1201.5289

Continuous-wave non-classical light with GHz squeezing bandwidth

Stefan Ast·Aiko Samblowski·Moritz Mehmet·Sebastian Steinlechner·Tobias Eberle·Roman Schnabel
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Abstract

Squeezed states can be employed for entanglement-based continuous-variable quantum key distribution, where the secure key rate is proportional to the bandwidth of the squeezing. We produced a non-classical continuous-wave laser field at the telecommunication wavelength of 1550 nm, which showed squeezing over a bandwidth of more than 2 GHz. The experimental setup used parametric down-conversion via a periodically poled potassium titanyl phosphate crystal (PPKTP). We did not use any resonant enhancement for the funda- mental wavelength, which should in principle allow a production of squeezed light over the full phase-matching bandwidth of several nanometers. We measured the squeezing to be up to 0.3 dB below the vacuum noise from 50 MHz to 2 GHz limited by the measuring bandwidth of the homodyne detector. The squeezing strength was possibly limited by thermal lensing inside the non-linear crystal.

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Stefan Ast, Aiko Samblowski, Moritz Mehmet, Sebastian Steinlechner, Tobias Eberle, Roman Schnabel. 2012-04-27. Continuous-wave non-classical light with GHz squeezing bandwidth. https://doi.org/10.1364/ol.37.002367

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