OSA's Digital Library

Journal of the Optical Society of America A

Journal of the Optical Society of America A


  • Editor: Franco Gori
  • Vol. 31, Iss. 1 — Jan. 1, 2014
  • pp: 35–40

Analog-to-digital optical waveguide conversion at sampling periods greater than the free-space wavelength

Tarek A. Ramadan  »View Author Affiliations

JOSA A, Vol. 31, Issue 1, pp. 35-40 (2014)

View Full Text Article

Enhanced HTML    Acrobat PDF (641 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



Nyquist sampling theorem reveals the possibility of sampling the continuous refractive index profiles of optical waveguides at periods greater than the free-space wavelength, λo. Binary encoding of these analog waveguides is investigated using the zero-order effective medium theory, while conserving the quantization of the modal spectrum implied by their boundary conditions. Both analytical and numerical approaches are developed for this analog-to-digital (A-to-D) conversion. An example is presented for the A-to-D conversion of a graded index waveguide with a hyperbolic secant profile at a sample period of 1.3λo. The results are confirmed using a beam propagation method.

© 2013 Optical Society of America

OCIS Codes
(050.1380) Diffraction and gratings : Binary optics
(130.3120) Integrated optics : Integrated optics devices
(230.4170) Optical devices : Multilayers
(230.7370) Optical devices : Waveguides
(260.2065) Physical optics : Effective medium theory
(310.4165) Thin films : Multilayer design

ToC Category:
Optical Devices

Original Manuscript: October 7, 2013
Manuscript Accepted: November 4, 2013
Published: December 4, 2013

Tarek A. Ramadan, "Analog-to-digital optical waveguide conversion at sampling periods greater than the free-space wavelength," J. Opt. Soc. Am. A 31, 35-40 (2014)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. I. Molina-Fernandez, A. Ortega-Monux, and J. G. Wanguemert-Perez, “Improving multimode interference couplers performance through index profile engineering,” J. Lightwave Technol. 27, 1307–1314 (2009). [CrossRef]
  2. U. Levy, M. Nezhad, H.-C. Kim, C.-H. Tsai, L. Pang, and Y. Fainman, “Implementation of a graded-index medium by use of subwavelength structures with graded fill factor,” J. Opt. Soc. Am. A 22, 724–733 (2005). [CrossRef]
  3. M. Born and E. Wolf, Principles of Optics, 6th ed. (Pergamon, 1980), Chap. 14, pp. 705–708.
  4. C. R. Pollock, Fundamentals of Optoelectronics, 1st ed. (Irwin, 1994), Chap. 9, pp. 243–270.
  5. M. Schwartz, Information Transmission, Modulation, and Noise, 4th ed. (McGraw-Hill, 1990), Chap. 3, pp. 96–100.
  6. T. Ramadan, “Sturm-sequence properties of recurrence dispersion functions of periodic waveguide arrays: theory and applications,” J. Lightwave Technol. 27, 4548–4562 (2009). [CrossRef]
  7. K. Muro and K. Shiraishi, “Poly-Si/SiO2 laminated walk-off polarizer having a beam-splitting angle of more than 20°,” J. Lightwave Technol. 16, 127–133 (1998). [CrossRef]
  8. A. Delage, S. Janz, B. Lamontagne, A. Bogdanov, D. Dalacu, D.-X. Xu, and K. P. Yap, “Monolithically integrated asymmetric graded and step-index couplers for microphotonic waveguides,” Opt. Express 14, 148–161 (2006). [CrossRef]
  9. S. Wakui, J. Nakamura, and A. Natori, “First-principles calculations of dielectric constants for ultrathin SiO2 films,” J. Vac. Sci. Technol. B 24, 1992–1996 (2006). [CrossRef]
  10. G. Zhang, M. Yu, C. Tung, and G. Lo, “Quantum size effects on dielectric constants and optical absorption of ultrathin silicon films,” IEEE Electron Dev. Lett. 29, 1302–1305 (2008).
  11. H. Nishihara, M. Haruna, and T. Sukara, Optical Integrated Circuits (McGraw-Hill, 1989), Chap. 2, pp. 21–25.
  12. V. V. Kotlyar, A. A. Kovalev, Y. R. Triandafilov, and A. G. Nalimov, “Simulation of propagation of modes in planar gradient-index hyperbolic secant waveguide,” in 11th International Conference on Laser and Fiber-Optical Networks Modeling (LFNM), Kharkov, Ukraine, September5–8, 2011.
  13. Y. P. Li and C. H. Henry, “Silica-based optical integrated circuits,” IEE Proc. Optoelectron. 143, 263–280 (1996). [CrossRef]
  14. D. Yevick and W. Bardyszewski, “Correspondence of variational finite-difference (relaxation) and imaginary-distance propagation methods for modal analysis,” Opt. Lett. 17, 329–330 (1992). [CrossRef]
  15. G. R. Hadley, “Transparent boundary conditions for the beam propagation method,” IEEE J. Quantum Electron. 28, 363–370 (1992). [CrossRef]
  16. K. S. Chiang, “Construction of refractive-index profiles of planar dielectric waveguides from the distribution of effective indexes,” J. Lightwave Technol. 3, 385–391 (1985). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited