dorsal/arxiv
View SchemaThe effects of time delays in adaptive phase measurements
| Authors | D. W. Berry, H. M. Wiseman |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0010059 |
| URL | https://arxiv.org/abs/quant-ph/0010059 |
| DOI | 10.1080/09500340108230953 |
| Journal | Journal of Modern Optics 48, 797 (2001) |
Abstract
It is not possible to make measurements of the phase of an optical mode using linear optics without introducing an extra phase uncertainty. This extra phase variance is quite large for heterodyne measurements, however it is possible to reduce it to the theoretical limit of log(n)/(4n^2) using adaptive measurements. These measurements are quite sensitive to experimental inaccuracies, especially time delays and inefficient detectors. Here it is shown that the minimum introduced phase variance when there is a time delay of tau is tau/(8n). This result is verified numerically, showing that the phase variance introduced approaches this limit for most of the adaptive schemes using the best final phase estimate. The main exception is the adaptive mark II scheme with simplified feedback, which is extremely sensitive to time delays. The extra phase variance due to time delays is considered for the mark I case with simplified feedback, verifying the tau/2 result obtained by Wiseman and Killip both by a more rigorous analytic technique and numerically.
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"abstract": "It is not possible to make measurements of the phase of an optical mode using\nlinear optics without introducing an extra phase uncertainty. This extra phase\nvariance is quite large for heterodyne measurements, however it is possible to\nreduce it to the theoretical limit of log(n)/(4n^2) using adaptive\nmeasurements. These measurements are quite sensitive to experimental\ninaccuracies, especially time delays and inefficient detectors. Here it is\nshown that the minimum introduced phase variance when there is a time delay of\ntau is tau/(8n). This result is verified numerically, showing that the phase\nvariance introduced approaches this limit for most of the adaptive schemes\nusing the best final phase estimate. The main exception is the adaptive mark II\nscheme with simplified feedback, which is extremely sensitive to time delays.\nThe extra phase variance due to time delays is considered for the mark I case\nwith simplified feedback, verifying the tau/2 result obtained by Wiseman and\nKillip both by a more rigorous analytic technique and numerically.",
"arxiv_id": "quant-ph/0010059",
"authors": [
"D. W. Berry",
"H. M. Wiseman"
],
"categories": [
"quant-ph"
],
"doi": "10.1080/09500340108230953",
"journal_ref": "Journal of Modern Optics 48, 797 (2001)",
"title": "The effects of time delays in adaptive phase measurements",
"url": "https://arxiv.org/abs/quant-ph/0010059"
},
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