Abstract

We present theoretical and experimental results which demonstrate the superior sensitivity of swept source (SS) and Fourier domain (FD) optical coherence tomography (OCT) techniques over the conventional time domain (TD) approach. We show that SS- and FD-OCT have equivalent expressions for system signal-to-noise ratio which result in a typical sensitivity advantage of 20–30dB over TD-OCT. Experimental verification is provided using two novel spectral discrimination (SD) OCT systems: a differential fiber-based 800nm FD-OCT system which employs deep-well photodiode arrays, and a differential 1300nm SS-OCT system based on a swept laser with an 87nm tuning range.

© 2003 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |

  1. D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, and C. A. Puliafito, "Optical coherence tomography," Science 254, 1178-1181 (1991).
    [CrossRef] [PubMed]
  2. A. F. Fercher, C. K. Hitzenberger, G. Kamp, and S. Y. Elzaiat, "Measurement of Intraocular Distances by Backscattering Spectral Interferometry," Opt. Commun. 117, 43-48 (1995).
    [CrossRef]
  3. G. Häusler and M. W. Lindner, ""Coherence Radar" and "Spectral Radar"�??New Tools for Dermatological Diagnosis," J. Biomed. Opt. 3, 21-31 (1998).
    [CrossRef]
  4. M. Wojtkowski, R. Leitgeb, A. Kowalczyk, T. Bajraszewski, and A. F. Fercher, "In vivo human retinal imaging by Fourier domain optical coherence tomography," J. Biomed. Opt. 7, 457-463 (2002).
    [CrossRef] [PubMed]
  5. M. Wojtkowski, A. Kowalczyk, R. Leitgeb, and A. F. Fercher, "Full range complex spectral optical coherence tomography technique in eye imaging," Opt. Lett. 27, 1415-1417 (2002).
    [CrossRef]
  6. S. R. Chinn, E. A. Swanson, and J. G. Fujimoto, "Optical coherence tomography using a frequency-tunable optical source," Opt. Lett. 22, 340-342 (1997).
    [CrossRef] [PubMed]
  7. B. Golubovic, B. E. Bouma, G. J. Tearney, and J. G. Fujimoto, "Optical frequency-domain reflectometry using rapid wavelength tuning of a Cr4+:forsterite laser," Opt. Lett. 22, 1704-1706 (1997).
    [CrossRef]
  8. F. Lexer, C. K. Hitzenberger, A. F. Fercher, and M. Kulhavy, "Wavelength-tuning interferometry of intraocular distances," Appl. Opt. 36, 6548-6553 (1997).
    [CrossRef]
  9. U. H. P. Haberland, V. Blazek, and H. J. Schmitt, "Chirp Optical Coherence Tomography of Layered Scattering Media," J. of Biomed. Opt. 3, 259-266 (1998).
    [CrossRef]
  10. R. Leitgeb, C. K. Hitzenberger, and A. F. Fercher, "Performance of fourier domain vs. time domain optical coherence tomography," Opt. Express 11, 889-894 (2003).
    [CrossRef] [PubMed]
  11. E. A. Swanson, D. Huang, M. R. Hee, J. G. Fujimoto, C. P. Lin, and C. A. Puliafito, "High-Speed Optical Coherence Domain Reflectometry," Opt. Lett. 17, 151-153 (1992).
    [CrossRef] [PubMed]
  12. M. A. Choma, C. Yang, and J. A. Izatt, "Instantaneous quadrature low coherence interferometry with 3x3 fiber optic couplers," Accepted to Opt. Lett. (2003).
    [CrossRef]
  13. A. M. Rollins and J. A. Izatt, "Optimal interferometer designs for optical coherence tomography," Opt. Lett. 24, 1484-1486 (1999).
    [CrossRef]
  14. S. U. Pillai, Array Signal Processing (Springer-Verlag, New York, 1989).
    [CrossRef]
  15. A. G. Podoleanu, "Unbalanced versus balanced operation in an optical coherence tomography system," Appl. Opt. 39, 173-182 (2000).
    [CrossRef]
  16. C. Dorrer, N. Belabas, J. P. Likforman, and M. Joffre, "Spectral resolution and sampling issues in Fourier-transform spectral interferometry," J. Opt. Soc. Am. B 17, 1795-1802 (2000).
    [CrossRef]

Appl. Opt. (2)

J. Biomed. Opt. (2)

G. Häusler and M. W. Lindner, ""Coherence Radar" and "Spectral Radar"�??New Tools for Dermatological Diagnosis," J. Biomed. Opt. 3, 21-31 (1998).
[CrossRef]

M. Wojtkowski, R. Leitgeb, A. Kowalczyk, T. Bajraszewski, and A. F. Fercher, "In vivo human retinal imaging by Fourier domain optical coherence tomography," J. Biomed. Opt. 7, 457-463 (2002).
[CrossRef] [PubMed]

J. of Biomed. Opt. (1)

U. H. P. Haberland, V. Blazek, and H. J. Schmitt, "Chirp Optical Coherence Tomography of Layered Scattering Media," J. of Biomed. Opt. 3, 259-266 (1998).
[CrossRef]

J. Opt. Soc. Am. B (1)

Opt. Commun. (1)

A. F. Fercher, C. K. Hitzenberger, G. Kamp, and S. Y. Elzaiat, "Measurement of Intraocular Distances by Backscattering Spectral Interferometry," Opt. Commun. 117, 43-48 (1995).
[CrossRef]

Opt. Express (1)

Opt. Lett. (6)

Science (1)

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, and C. A. Puliafito, "Optical coherence tomography," Science 254, 1178-1181 (1991).
[CrossRef] [PubMed]

Other (1)

S. U. Pillai, Array Signal Processing (Springer-Verlag, New York, 1989).
[CrossRef]

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (4)

Fig. 1.
Fig. 1.

A) Differential SS-OCT setup. The output of detectors 1 and 2 are differenced in software. B) Differential FD-OCT setup. Differential detection is accomplished by dithering the phase of the reference arm field by 180°° with a piezo-mounted mirror on alternate scans. C) Swept source output measured with an optical spectrum analyzer (OSA). The apparent modulation appearing in the OSA plot is an artifact of spectral resolution and sweep time setting of the OSA. D) Czerny-Turner grating spectrometer (Spec) employed in FD-OCT system. D, detector; DG, diffraction grating; f, focal length of reflective optical element; M, mirror; PDA, photodiode array; PZT, piezoelectric actuator.

Fig. 2.
Fig. 2.

Sensitivity advantage of SS-OCT and FD-OCT over conventional TD-OCT with a Gaussian source at 1300nm. Sensitivity advantage is defined as SNR sdoct /SNR tdoct and expressed in dB.

Fig. 3.
Fig. 3.

A) SS-OCT peaks from a calibrated -47dB reflector at 200µm spacing increments. B) FD-OCT peaks from a calibrated -38dB reflector at 100µm increments. The shoulders (Sh) are artifacts of interpolation of the data from wavelength to wavenumber [16]. Imperfections in software differencing lead to residual DC (R) and autocorrelation (AC) peaks.

Fig. 4.
Fig. 4.

Comparison of predicted TD-OCT SNR to predicted and experimental SNR of SDOCT. The additional losses in the final column include measured recoupling inefficiencies in the sample arm and spectrometer losses. All predicted SNR values assume shot noise-limited detection. The TD-OCT predicted is based on a setup per reference 11. Briefly, it is a 2×2 fiber coupler-based Michelson interferometer with a broadband SLD source, a scanning reference arm mirror, and a single photodetector. The splitting ratio of the 2×2 coupler is 50%.

Equations (10)

Equations on this page are rendered with MathJax. Learn more.

P D i ( k ) = E D i ( k ) 2 = S ( k ) R R + S ( k ) R s + 2 S ( k ) R R R S cos ( 2 k Δ x + φ i ) .
D i [ k m ] = 1 2 i ρ S [ k m ] ( R R + R S + 2 R R R S cos ( 2 k m Δ x + φ i ) ) .
D [ x n ] = m = 1 M D i [ k m ] Exp [ j 2 k m x n ] .
D [ x n ] = m = 1 M [ ( D 0 [ k m ] D DC [ k m ] ) + j ( D 90 [ k m ] D DC [ k m ] ) ] Exp [ j 2 k m x n ] .
D [ x n ] = m = 1 M ( 1 2 D 1 [ k m ] D 2 [ k m ] ) Exp [ j 2 k m x n ] .
D [ x n = ± Δ x ] = 1 2 ρ R R R S m = 1 M S [ k m ] = 1 2 ρ R R R S S ssoct .
σ x = m = 1 M σ 2 [ k m ] = e ρ R R S ssoct B ssoct ,
SNR ssoct = ρ R S S ssoct 4 e B ssoct M ρ R S S tdoct 4 e B ssoct .
SNR tdoct = ρ R S S tdoct 2 e B tdoct .
SNR sdoct = ρ S R S Δ t 2 e .

Metrics