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Publication Citation: Exploiting shot noise correlations in the photodetection of ultrashort optical pulse trains

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Author(s): Franklyn J. Quinlan; Tara M. Fortier; Haifeng (. Jiang; Archita Hati; Craig W. Nelson; Yang Fu; Joe Campbell; Scott A. Diddams;
Title: Exploiting shot noise correlations in the photodetection of ultrashort optical pulse trains
Published: March 10, 2013
Abstract: Photocurrent shot noise represents the fundamental quantum limit of amplitude, phase and timing measurements of optical signals. It is generally assumed that non-classical states of light must be employed to alter the standard, time-invariant shot noise detection limit. However, in the case of the detection of periodic signals, correlations in the shot noise spectrum can impact the quantum limit of detection. Here we show how these correlations can be exploited to improve shot noise-limited optical pulse timing measurements by several orders of magnitude. This has allowed us to realize a photodetected pulse train timing noise floor at an unprecedented 25 zeptoseconds/sqrt(Hz), which is ~5 dB below the level predicted by the accepted time-invariant shot noise behavior. This new understanding of the shot noise of time-varying signals can be exploited to greatly improve photonic systems, impacting a wide range of communication, navigation, and precision measurement applications.
Citation: Nature Photonics
Volume: 7
Pages: pp. 290 - 293
Keywords: Microwave Photonics;Phase Noise;Shot noise;Timing Jitter;Ultrafast Optics
Research Areas: Physics
DOI: http://dx.doi.org/10.1038/NPHOTON.2013.33  (Note: May link to a non-U.S. Government webpage)
PDF version: PDF Document Click here to retrieve PDF version of paper (232KB)