Direct-phase and amplitude digitalization based on free-space interferometry

Vladimir Kleiner, Arkady Rudnitsky, Zeev Zalevsky

Research output: Contribution to journalArticlepeer-review


A novel ADC configuration that can be characterized as a photonic-domain flash analog-to-digital convertor operating based upon free-space interferometry is proposed and analysed. The structure can be used as the front-end of a coherent receiver as well as for other applications. Two configurations are considered: the first, 'direct free-space interference', allows simultaneous measuring of the optical phase and amplitude; the second, 'extraction of the ac component of interference by means of pixel-by-pixel balanced photodetection', allows only phase digitization but with significantly higher sensitivity. For both proposed configurations, we present Monte Carlo estimations of the performance limitations, due to optical noise and photo-current noise, at sampling rates of 60 giga-samples per second. In terms of bit resolution, we simulated multiple cases with growing complexity of up to 4 bits for the amplitude and up to 6 bits for the phase. The simulations show that the digitization errors in the optical domain can be reduced to levels close to the quantization noise limits. Preliminary experimental results validate the fundamentals of the proposed idea.

Original languageEnglish
Article number125704
JournalJournal of Optics (United Kingdom)
Issue number12
StatePublished - Dec 2017

Bibliographical note

Publisher Copyright:
© 2017 IOP Publishing Ltd.


  • analog optical signal processing
  • information processing
  • interferometry


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