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OSA Advanced Photonics Congress

Ultra-low Raman Noise Correlated Photon-Pair Generation in a Dispersion Engineered As2S3 Waveguide

Matthew J. Collins, Alex S. Clark, J. He, Duk‐Yong Choi, Robert J. Williams, A. C. Judge, Michael J. Steel, Barry Luther‐Davies, Chunle Xiong, Benjamin J. Eggleton

Published Jan 1, 2012• 0 citations
Publisher

Abstract

We demonstrate ultra-low Raman noise generation of correlated photon-pairs in a dispersion-engineered 10mm As2S3 waveguide at room temperature. We show a coincidence-to-accidental ratio (CAR) of 16.8, a 250 times increase compared with previously published results.
DOI
10.1364/bgpp.2012.jw4d.6

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We report the characterization of correlated photon pairs generated in dispersion-engineered silicon slow-light photonic crystal waveguides pumped by picosecond pulses. We found that taking advantage of the 15-nm flat-band slow-light window (vg~c/30), the bandwidth for correlated photon-pair generation in 96- and 196-μm-long waveguides was at least 11.2 nm, while a 396-μm-long waveguide reduced the bandwidth to 8 nm (only half of the slow-light bandwidth due to the increased impact of phase matching in a longer waveguide). The key metrics for a photon-pair source: coincidence to accidental ratio (CAR) and pair brightness were measured to be a maximum 33 at a pair generation rate of 0.004 pair per pulse in a 196- μm-long waveguide. Within the measurement errors, the maximum CAR achieved in 96-, 196-, and 396-μm-long waveguides is constant. The noise analysis shows that detector dark counts, leaked pump light, linear and nonlinear losses, multiple pair generation, and detector jitter are the limiting factors to the CAR performance of the sources.
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