All-fiber common-path optical coherence tomography: Sensitivity optimization and system analysis

Utkarsh Sharma, Nathaniel M. Fried, Jin U. Kang

Research output: Contribution to journalArticlepeer-review

89 Scopus citations


A fully integrated all-fiber implementation of common-path interferometer-based optical coherence tomography (OCT) has been successfully demonstrated. Unlike conventional Michelson-based OCT systems, there is no separate reference arm as the reference signal is derived from the probe-end back reflection. This leads to "downlead insensitivity," which makes the device more compatible with existing endoscopic medical instruments. We also theoretically analyze the optimization of system sensitivity in balanced and unbalanced detection. We have conducted experiments to confirm some of our signal-to-noise ratio (SNR) analysis, which are in excellent agreement with the theory. Interestingly, our analysis predicts existence of much higher beat noise in common-path OCT as compared with the conventional OCT. We predict a maximum upper limit of only 6-dB improvement in the SNR when the balanced detection is used, as compared with the unbalanced detection.

Original languageEnglish (US)
Pages (from-to)799-805
Number of pages7
JournalIEEE Journal on Selected Topics in Quantum Electronics
Issue number4
StatePublished - Jul 2005


  • Medical and biological imaging
  • Medical optics instrumentation
  • Noise in imaging systems
  • Optical coherence tomography (OCT)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Atomic and Molecular Physics, and Optics


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