OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 18 — Aug. 31, 2009
  • pp: 16027–16028
« Show journal navigation

1 μs tunable delay using para-metric mixing and optical phase conjugation in Si waveguides: comment

N. Alic, C. J. McKinstrie, S. Namiki, and S. Radic  »View Author Affiliations


Optics Express, Vol. 17, Issue 18, pp. 16027-16028 (2009)
http://dx.doi.org/10.1364/OE.17.016027


View Full Text Article

Acrobat PDF (176 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

A recent report of 1μs all-optical delay using silicon convertor elements in the 1550-nm band is analyzed.

© 2009 OSA

In recently published work [1

1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

], the authors claim the introduction of a new delay architecture and experimental measurement of a 1-μs tunable delay. The purpose of this comment is to point out that these claims are not supported by the material reported in [1

1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

]. Indeed, the delay scheme in [1

1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

] appears to be identical to the scheme proposed and demonstrated by Namiki [2

2. S. Namiki, “Wide-Band and -Range Tunable Dispersion Compensation Through Parametric Wavelength Conversion and Dispersive Optical Fibers,” J. Lightwave Technol. 26(1), 28–35 (2008). [CrossRef]

,3

3. S. Namiki, and T. Kurosu, “17 ns Tunable Delay for Picosecond Pulses through Simultaneous and Independent Control of Delay and Dispersion Using Cascaded Parametric Processes,” Proc. ECOC 2008, postdeadline paper Th.3.C.3, Brussels, Belgium.

]. Specifically, the concept described in [1

1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

] is a reduced version of the Namiki scheme that does not include higher-order dispersion compensation. This simplification was enabled by the use of a moderate (10Gbps) data rate and, contrary to the authors’ claim, cannot be extended to considerably higher data rates. The true difference introduced in [1

1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

] is the use of a silicon waveguide instead of a high confinement fiber. Its performance appears to be a main reason for the system results reported in [1

1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

]. It appears that the claim of a measured all-optical delay is not substantiated as [1

1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

] reports only a partial experimental result. Specifically, only two of the three required wavelength conversions are reported, reducing the measured architecture to a new, yet unclassified functionality: each delay setting corresponds to a different wavelength output. We believe that it was reasonable to use only two conversions to demonstrate the principle of the scheme [2

2. S. Namiki, “Wide-Band and -Range Tunable Dispersion Compensation Through Parametric Wavelength Conversion and Dispersive Optical Fibers,” J. Lightwave Technol. 26(1), 28–35 (2008). [CrossRef]

,3

3. S. Namiki, and T. Kurosu, “17 ns Tunable Delay for Picosecond Pulses through Simultaneous and Independent Control of Delay and Dispersion Using Cascaded Parametric Processes,” Proc. ECOC 2008, postdeadline paper Th.3.C.3, Brussels, Belgium.

]. However, as it is now well established, subsequent demonstrations [5

5. N. Alic, E. Myslivets, S. Moro, B. P. P. Kuo, R. M. Jopson, C. J. McKinstrie, and S. Radic, “1.83-μs wavelength-transparent all-optical delay,” Proc. OFC 2009, postdeadline paper PDP-1, San Diego, CA.

], and particularly those aiming for record performance, should perform all three conversions to be relevant.

The experiment reported in [1

1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

] is, to the authors’ credit, an attempt to perform a complex system measurement. Unfortunately, the reported measurements fall short of the rigorous requirements outlined above and should not be trivialized. They are of a more fundamental nature inherent in physical properties of silicon and should not be rationalized by the statement that the addition of the third conversion stage “will have no impact on the dispersion management and the delay range.” This rather important assessment is in direct contradiction to (a) the measured penalty and (b) the means used to measure the performance of the partial (two-conversion) architecture. Indeed, the measured penalty of 4.5dB represents a considerable impairment in any system operating at 10Gbps, even if the reader does allow that “wavelength conversion based on the Si waveguide will result in a small power penalty (~ 1 dB) to the system”. If only two conversions contribute a 4.5dB penalty, a question remains about the total penalty accumulated after a third conversion with an efficiency of only −20dB [1

1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

]. Would one actually measure BER below 10−9 by completing the experiment? The last issue becomes even more relevant if one considers the fact that the authors chose to measure performance using a short (223-1), rather than a standard (231-1) pattern length. This is in spite of well-known pattern-dependent effects expected in non-ideal converters such as silicon. Two-photon absorption and pump depletion effects are only two of many impairment mechanisms that a researcher in field would test before deciding to use a non-standard test-word length. Indeed, the risks of understating the system penalty by using a short, rather than standard (231-1) test pattern in wavelength converters were quantified more than a decade ago [6

6. J. M. Wiesenfeld, J. S. Perino, A. H. Gnauck, and B. Glance, “Bit error rate performance for wavelength conversion at 20Gbit/s,” Electron. Lett. 30(9), 720–721 (1994). [CrossRef]

]. The reported back-to-back measurement (−19dB SNR at a BER of 10−9) is significantly below the standard reference level of about −34dBm [7

7. L. M. Lunardi, S. Chandrasekhar, A. H. Gnauck, C. A. Burrus, R. A. Ha, J. W. Sulhoff, and J. L. Zyskind, “A 12-Gb/s High-Performance, High-Sensitivity Monolithic p-i-n/HBT Photoreceiver Module for Long-Wavelength Transmission Systems,” IEEE Photon. Technol. Lett. 7(2), 182–184 (1995). [CrossRef]

], suggesting a large penalty which might mask other effects in this experiment.

References and links

1.

Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]

2.

S. Namiki, “Wide-Band and -Range Tunable Dispersion Compensation Through Parametric Wavelength Conversion and Dispersive Optical Fibers,” J. Lightwave Technol. 26(1), 28–35 (2008). [CrossRef]

3.

S. Namiki, and T. Kurosu, “17 ns Tunable Delay for Picosecond Pulses through Simultaneous and Independent Control of Delay and Dispersion Using Cascaded Parametric Processes,” Proc. ECOC 2008, postdeadline paper Th.3.C.3, Brussels, Belgium.

4.

J. Ren, N. Alic, E. Myslivets, R. E. Saperstein, C. J. McKinstrie, R. M. Jopson, A. H. Gnauck, P. A. Andrekson, and S. Radic, “12.47 ns continuously-tunable two-pump parametric delay,” Proc. ECOC 2006, postdeadline paper Th4.4.3, Cannes, France.

5.

N. Alic, E. Myslivets, S. Moro, B. P. P. Kuo, R. M. Jopson, C. J. McKinstrie, and S. Radic, “1.83-μs wavelength-transparent all-optical delay,” Proc. OFC 2009, postdeadline paper PDP-1, San Diego, CA.

6.

J. M. Wiesenfeld, J. S. Perino, A. H. Gnauck, and B. Glance, “Bit error rate performance for wavelength conversion at 20Gbit/s,” Electron. Lett. 30(9), 720–721 (1994). [CrossRef]

7.

L. M. Lunardi, S. Chandrasekhar, A. H. Gnauck, C. A. Burrus, R. A. Ha, J. W. Sulhoff, and J. L. Zyskind, “A 12-Gb/s High-Performance, High-Sensitivity Monolithic p-i-n/HBT Photoreceiver Module for Long-Wavelength Transmission Systems,” IEEE Photon. Technol. Lett. 7(2), 182–184 (1995). [CrossRef]

8.

T. Torounidis, P. A. Andrekson, and B. E. Olsson, “Fiber-optical parametric amplifier with 70-dB gain,” Photon. Technol. Lett. 18(10), 1194–1196 (2006). [CrossRef]

9.

V. G. Ta'eed, M. D. Pelusi, and B. J. Eggleton, “All-Optical Wavelength Conversion of 80 Gb/s Signal in Highly Nonlinear Serpentine Chalcogenide Planar Waveguides,” Proc. OFC 2008, paper OMP2, San Diego, CA.

ToC Category:
Nonlinear Optics

History
Original Manuscript: June 1, 2009
Revised Manuscript: June 25, 2009
Manuscript Accepted: June 26, 2009
Published: August 25, 2009

Citation
N. Alic, C. J. McKinstrie, S. Namiki, and S. Radic, "1 μs tunable delay using para-metric mixing and optical phase conjugation
in Si waveguides: comment," Opt. Express 17, 16027-16028 (2009)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-17-18-16027


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. Y. Dai, X. Chen, Y. Okawachi, A. C. Turner-Foster, M. A. Foster, M. Lipson, A. L. Gaeta, and C. Xu, “1 micros tunable delay using parametric mixing and optical phase conjugation in Si waveguides,” Opt. Express 17(9), 7004–7010 (2009). [CrossRef] [PubMed]
  2. S. Namiki, “Wide-Band and -Range Tunable Dispersion Compensation Through Parametric Wavelength Conversion and Dispersive Optical Fibers,” J. Lightwave Technol. 26(1), 28–35 (2008). [CrossRef]
  3. S. Namiki, and T. Kurosu, “17 ns Tunable Delay for Picosecond Pulses through Simultaneous and Independent Control of Delay and Dispersion Using Cascaded Parametric Processes,” Proc. ECOC 2008, postdeadline paper Th.3.C.3, Brussels, Belgium.
  4. J. Ren, N. Alic, E. Myslivets, R. E. Saperstein, C. J. McKinstrie, R. M. Jopson, A. H. Gnauck, P. A. Andrekson, and S. Radic, “12.47 ns continuously-tunable two-pump parametric delay,” Proc. ECOC 2006, postdeadline paper Th4.4.3, Cannes, France.
  5. N. Alic, E. Myslivets, S. Moro, B. P. P. Kuo, R. M. Jopson, C. J. McKinstrie, and S. Radic, “1.83-μs wavelength-transparent all-optical delay,” Proc. OFC 2009, postdeadline paper PDP-1, San Diego, CA.
  6. J. M. Wiesenfeld, J. S. Perino, A. H. Gnauck, and B. Glance, “Bit error rate performance for wavelength conversion at 20Gbit/s,” Electron. Lett. 30(9), 720–721 (1994). [CrossRef]
  7. L. M. Lunardi, S. Chandrasekhar, A. H. Gnauck, C. A. Burrus, R. A. Ha, J. W. Sulhoff, and J. L. Zyskind, “A 12-Gb/s High-Performance, High-Sensitivity Monolithic p-i-n/HBT Photoreceiver Module for Long-Wavelength Transmission Systems,” IEEE Photon. Technol. Lett. 7(2), 182–184 (1995). [CrossRef]
  8. T. Torounidis, P. A. Andrekson, and B. E. Olsson, “Fiber-optical parametric amplifier with 70-dB gain,” Photon. Technol. Lett. 18(10), 1194–1196 (2006). [CrossRef]
  9. V. G. Ta'eed, M. D. Pelusi, and B. J. Eggleton, “All-Optical Wavelength Conversion of 80 Gb/s Signal in Highly Nonlinear Serpentine Chalcogenide Planar Waveguides,” Proc. OFC 2008, paper OMP2, San Diego, CA.

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