OPTICAL heterodyNE detection PHOTONICS INSIGHTS
Optical heterodyne detection
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Arnaud ROGEMONT 1, Aurélien COILLET 1, Tiphaine DELSALLE 2, Benjamin SPRENGER 2, Romain STOMP 3 and Benoît CLUZEL 1, *
1
Université Bourgogne Europe, Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR6303, Dijon, France
2
Menlo Systems GmbH, Martinsried, Germany
3
Zurich Instruments AG, Technoparkstrasse 1, Zurich, Switzerland * benoit. cluzel @ ube. fr
Optical heterodyne detection has become one of the fundamental measurement techniques in modern photonics. Originally developed in radio-frequency communications to improve receiver sensitivity and frequency selectivity, the heterodyne principle was later transposed to optical frequencies following the emergence of coherent laser sources. This article reviews the physical principles of heterodyne detection from its historical origins in radio engineering to its implementation in modern optical systems.
Canadian stamp in honour of Reginald A. Fessenden, inventor of heterodyne detection. https:// doi. org / 10.1051 / photon / 202614023
Coherent detection encompasses all techniques based on the interference of an optical signal with a coherent reference wave, referred to as the local oscillator( LO), prior to conversion into an electrical signal by photodetection. This approach enables the information carried by both the amplitude and phase of the optical field to be transferred to the radio-frequency domain, where it can be detected and electronically processed with high sensitivity. Two specific regimes can be distinguished depending on the frequency difference between the optical signal and the local oscillator. When the two waves have the same optical frequency, the detection scheme is referred to as homodyne detection. Conversely, when a non-zero frequency offset is introduced between the signal and the local oscillator, the optical beat signal is shifted to an intermediate frequency, resulting in heterodyne detection.
Basic concepts from radiocommunications
Heterodyne detection has its historical roots in radio communications, where engineers faced the difficulty of processing information carried by electromagnetic waves at frequencies far beyond the bandwidth of available electronic circuits. The heterodyne principle consists of mixing the received signal with a locally generated oscillation so as to translate its spectrum to a lower intermediate frequency while preserving its
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