Noise in homodyne and heterodyne detection

Horace P. Yuen, Vincent W.S. Chan

Research output: Contribution to journalArticlepeer-review

615 Scopus citations


Quantum-mechanical calculations of the mean-square fluctuation spectra in optical homodyning and heterodyning are made for arbitrary input and local-oscillator quantum states. In addition to the unavoidable quantum fluctuations, it is shown that excess noise from the local oscillator always affects homodyning and, when it is broadband, also heterodyning. Both the quantum and the excess noise of the local oscillator can be eliminated by coherent subtraction of the two outputs of a 50-50 beam splitter. This result also demonstrates the fact that the basic quantum noise in homodyning and heterodyning is signal quantum fluctuation, not local-oscillator shot noise.

Original languageEnglish (US)
Pages (from-to)177-179
Number of pages3
JournalOptics Letters
Issue number3
StatePublished - Mar 1983

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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