Abstract

Optical signal-to-noise ratio (OSNR) monitoring is indispensable for ensuring robust and flexible optical networks that provide failure diagnosis, dynamic lightpath provisioning and modulation format adaptation. We propose and experimentally demonstrate a low-cost, modulation-format-independent OSNR monitoring scheme utilizing reduced-complexity coherent receptions, electrical filtering and radio frequency (RF) power measurements. By measuring the RF power of the coherently received baseband signals at three different frequency components, the proposed OSNR monitor is also insensitive to spectral narrowing induced by cascaded wavelength selective switches (WSSs). We experimentally demonstrate accurate data-format-transparent and filtering-effect-insensitive OSNR monitoring for 25-Gbaud dual-polarization (DP-) transmissions with QPSK, 16-QAM and 64-QAM signals over various distances with different amount of filtering effects by cascaded WSSs. We further characterize the influence of different system parameters, such as the bandwidth of the electrical low-pass filter, the laser frequency offset and laser linewidth on the accuracy of the proposed OSNR monitor. The robustness of the proposed OSNR monitoring scheme to fiber nonlinearities, calibration parameter mismatches and variations of WSS parameters are also investigated.

© 2015 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Modulation format identification and OSNR monitoring using density distributions in Stokes axes for digital coherent receivers

Anlin Yi, Lianshan Yan, Hengjiang Liu, Lin Jiang, Yan Pan, Bin Luo, and Wei Pan
Opt. Express 27(4) 4471-4479 (2019)

Joint OSNR monitoring and modulation format identification in digital coherent receivers using deep neural networks

Faisal Nadeem Khan, Kangping Zhong, Xian Zhou, Waled Hussein Al-Arashi, Changyuan Yu, Chao Lu, and Alan Pak Tao Lau
Opt. Express 25(15) 17767-17776 (2017)

OSNR monitoring for QPSK and 16-QAM systems in presence of fiber nonlinearities for digital coherent receivers

Zhenhua Dong, Alan Pak Tao Lau, and Chao Lu
Opt. Express 20(17) 19520-19534 (2012)

References

  • View by:
  • |
  • |
  • |

  1. A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
    [Crossref]
  2. Q. Sui, A. P. T. Lau, and C. Lu, “Fast and robust blind chromatic dispersion estimation using auto-correlation of signal power waveform for digital coherent systems,” J. Lightwave Technol. 31(2), 306–312 (2013).
    [Crossref]
  3. S. J. Savory, “Digital coherent optical receivers: algorithms and subsystems,” IEEE J. Sel. Top. Quantum Electron. 16(5), 1164–1179 (2010).
    [Crossref]
  4. D. J. Ives, B. C. Thomsen, R. Maher, and S. J. Savory, “Estimating OSNR of equalised QPSK signals,” in Proc. Eur. Conf. Exhib. Opt. Commun. (ECOC), Geneva, Switzerland, Sep. 2011, Paper Tu.6.A.6.
  5. M. S. Faruk, Y. Mori, and K. Kikuchi, “In-Band estimation of optical signal-to-noise ratio from equalized signals in digital coherent receivers,” IEEE Photonics J. 6(1), 7800109 (2014).
    [Crossref]
  6. C. Zhu, A. V. Tran, S. Chen, L. B. Du, C. C. Do, T. Anderson, A. J. Lowery, and E. Skafidas, “Statistical moments-based OSNR monitoring for coherent optical systems,” Opt. Express 20(16), 17711–17721 (2012).
    [Crossref] [PubMed]
  7. Z. Dong, A. P. T. Lau, and C. Lu, “OSNR monitoring for QPSK and 16-QAM systems in presence of fiber nonlinearities for digital coherent receivers,” Opt. Express 20(17), 19520–19534 (2012).
    [Crossref] [PubMed]
  8. Z. Dong, Q. Sui, A. P. T. Lau, K. Zhong, L. Li, Z. Li, and C. Lu, “Optical performance monitoring in DSP-based coherent optical systems,” in Proc. Opt. Fiber Commun. (OFC), Los Angeles, CA, Mar. 2015, Paper W4D.1.
  9. C. C. Do, C. Zhu, and A. V. Tran, “Data-aided OSNR estimation using low-bandwidth coherent receivers,” IEEE Photon. Technol. Lett. 26(13), 1291–1294 (2014).
    [Crossref]
  10. X. Liu, Y. H. Kao, S. Chandrasekhar, I. Kang, S. Cabot, and L. L. Buhl, “OSNR monitoring method for OOK and DPSK based on optical delay interferometer,” IEEE Photon. Technol. Lett. 19(15), 1172–1174 (2007).
    [Crossref]
  11. S. Oda, J. Y. Yang, Y. Akasaka, K. Sone, Y. Aoki, M. Sekiya, and J. C. Rasmussen, “In-band OSNR monitor using an optical bandpass filter and optical power measurements for superchannel signals,” in Proc. Eur. Conf. Exhib. Opt. Commun. (ECOC), London, U. K., Sep. 2013, paper P.3.12.
    [Crossref]
  12. G. Nakagawa, S. Oda, K. Sone, Y. Aoki, T. Hoshida, and J. C. Rasmussen, “Demonstration of integrated optical path monitoring sub-system in CDCG-ROADM network,” in 2014 European Conference on Optical Communication (IEEE, 2014), P.4.1.
    [Crossref]
  13. C. Pulikkaseril, L. A. Stewart, M. A. Roelens, G. W. Baxter, S. Poole, and S. Frisken, “Spectral modeling of channel band shapes in wavelength selective switches,” Opt. Express 19(9), 8458–8470 (2011).
    [Crossref] [PubMed]
  14. Optical Monitoring for DWDM Systems. ITU-T recommendation G.697, June 2004.
  15. H. Rosenfeldt, I. Clarke, S. Frisken, G. Dash, X. Huang, H. Li, W. Cui, J. Zhang, J. Chen, Z. Kong, and S. Poole, “Miniaturized heterodyne channel monitor with tone detection,” in Optical Fiber Communication Conference, OSA Technical Digest (online) (Optical Society of America, 2015), paper W4D.7.
    [Crossref]
  16. VPIsystemsTM, “VPltransmission MakerTM”.
  17. Y. Sakamaki, T. Kawai, T. Komukai, M. Fukutoku, and T. Kataoka, “Evaluation of optical filtering penalty in digital coherent detection system,” IEICE Commun. Express 1(2), 54–59 (2012).

2014 (3)

M. S. Faruk, Y. Mori, and K. Kikuchi, “In-Band estimation of optical signal-to-noise ratio from equalized signals in digital coherent receivers,” IEEE Photonics J. 6(1), 7800109 (2014).
[Crossref]

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

C. C. Do, C. Zhu, and A. V. Tran, “Data-aided OSNR estimation using low-bandwidth coherent receivers,” IEEE Photon. Technol. Lett. 26(13), 1291–1294 (2014).
[Crossref]

2013 (1)

2012 (3)

2011 (1)

2010 (1)

S. J. Savory, “Digital coherent optical receivers: algorithms and subsystems,” IEEE J. Sel. Top. Quantum Electron. 16(5), 1164–1179 (2010).
[Crossref]

2007 (1)

X. Liu, Y. H. Kao, S. Chandrasekhar, I. Kang, S. Cabot, and L. L. Buhl, “OSNR monitoring method for OOK and DPSK based on optical delay interferometer,” IEEE Photon. Technol. Lett. 19(15), 1172–1174 (2007).
[Crossref]

Anderson, T.

Aoki, Y.

G. Nakagawa, S. Oda, K. Sone, Y. Aoki, T. Hoshida, and J. C. Rasmussen, “Demonstration of integrated optical path monitoring sub-system in CDCG-ROADM network,” in 2014 European Conference on Optical Communication (IEEE, 2014), P.4.1.
[Crossref]

Baxter, G. W.

Buhl, L. L.

X. Liu, Y. H. Kao, S. Chandrasekhar, I. Kang, S. Cabot, and L. L. Buhl, “OSNR monitoring method for OOK and DPSK based on optical delay interferometer,” IEEE Photon. Technol. Lett. 19(15), 1172–1174 (2007).
[Crossref]

Cabot, S.

X. Liu, Y. H. Kao, S. Chandrasekhar, I. Kang, S. Cabot, and L. L. Buhl, “OSNR monitoring method for OOK and DPSK based on optical delay interferometer,” IEEE Photon. Technol. Lett. 19(15), 1172–1174 (2007).
[Crossref]

Chagnon, M.

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

Chandrasekhar, S.

X. Liu, Y. H. Kao, S. Chandrasekhar, I. Kang, S. Cabot, and L. L. Buhl, “OSNR monitoring method for OOK and DPSK based on optical delay interferometer,” IEEE Photon. Technol. Lett. 19(15), 1172–1174 (2007).
[Crossref]

Chen, S.

Do, C. C.

C. C. Do, C. Zhu, and A. V. Tran, “Data-aided OSNR estimation using low-bandwidth coherent receivers,” IEEE Photon. Technol. Lett. 26(13), 1291–1294 (2014).
[Crossref]

C. Zhu, A. V. Tran, S. Chen, L. B. Du, C. C. Do, T. Anderson, A. J. Lowery, and E. Skafidas, “Statistical moments-based OSNR monitoring for coherent optical systems,” Opt. Express 20(16), 17711–17721 (2012).
[Crossref] [PubMed]

Dong, Z.

Du, L. B.

Faruk, M. S.

M. S. Faruk, Y. Mori, and K. Kikuchi, “In-Band estimation of optical signal-to-noise ratio from equalized signals in digital coherent receivers,” IEEE Photonics J. 6(1), 7800109 (2014).
[Crossref]

Frisken, S.

Fukutoku, M.

Y. Sakamaki, T. Kawai, T. Komukai, M. Fukutoku, and T. Kataoka, “Evaluation of optical filtering penalty in digital coherent detection system,” IEICE Commun. Express 1(2), 54–59 (2012).

Gao, Y.

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

Hoshida, T.

G. Nakagawa, S. Oda, K. Sone, Y. Aoki, T. Hoshida, and J. C. Rasmussen, “Demonstration of integrated optical path monitoring sub-system in CDCG-ROADM network,” in 2014 European Conference on Optical Communication (IEEE, 2014), P.4.1.
[Crossref]

Kang, I.

X. Liu, Y. H. Kao, S. Chandrasekhar, I. Kang, S. Cabot, and L. L. Buhl, “OSNR monitoring method for OOK and DPSK based on optical delay interferometer,” IEEE Photon. Technol. Lett. 19(15), 1172–1174 (2007).
[Crossref]

Kao, Y. H.

X. Liu, Y. H. Kao, S. Chandrasekhar, I. Kang, S. Cabot, and L. L. Buhl, “OSNR monitoring method for OOK and DPSK based on optical delay interferometer,” IEEE Photon. Technol. Lett. 19(15), 1172–1174 (2007).
[Crossref]

Kataoka, T.

Y. Sakamaki, T. Kawai, T. Komukai, M. Fukutoku, and T. Kataoka, “Evaluation of optical filtering penalty in digital coherent detection system,” IEICE Commun. Express 1(2), 54–59 (2012).

Kawai, T.

Y. Sakamaki, T. Kawai, T. Komukai, M. Fukutoku, and T. Kataoka, “Evaluation of optical filtering penalty in digital coherent detection system,” IEICE Commun. Express 1(2), 54–59 (2012).

Kikuchi, K.

M. S. Faruk, Y. Mori, and K. Kikuchi, “In-Band estimation of optical signal-to-noise ratio from equalized signals in digital coherent receivers,” IEEE Photonics J. 6(1), 7800109 (2014).
[Crossref]

Komukai, T.

Y. Sakamaki, T. Kawai, T. Komukai, M. Fukutoku, and T. Kataoka, “Evaluation of optical filtering penalty in digital coherent detection system,” IEICE Commun. Express 1(2), 54–59 (2012).

Lau, A. P. T.

Liu, X.

X. Liu, Y. H. Kao, S. Chandrasekhar, I. Kang, S. Cabot, and L. L. Buhl, “OSNR monitoring method for OOK and DPSK based on optical delay interferometer,” IEEE Photon. Technol. Lett. 19(15), 1172–1174 (2007).
[Crossref]

Lowery, A. J.

Lu, C.

Mori, Y.

M. S. Faruk, Y. Mori, and K. Kikuchi, “In-Band estimation of optical signal-to-noise ratio from equalized signals in digital coherent receivers,” IEEE Photonics J. 6(1), 7800109 (2014).
[Crossref]

Morsy-Osman, M.

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

Nakagawa, G.

G. Nakagawa, S. Oda, K. Sone, Y. Aoki, T. Hoshida, and J. C. Rasmussen, “Demonstration of integrated optical path monitoring sub-system in CDCG-ROADM network,” in 2014 European Conference on Optical Communication (IEEE, 2014), P.4.1.
[Crossref]

Oda, S.

G. Nakagawa, S. Oda, K. Sone, Y. Aoki, T. Hoshida, and J. C. Rasmussen, “Demonstration of integrated optical path monitoring sub-system in CDCG-ROADM network,” in 2014 European Conference on Optical Communication (IEEE, 2014), P.4.1.
[Crossref]

Plant, D. V.

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

Poole, S.

Pulikkaseril, C.

Rasmussen, J. C.

G. Nakagawa, S. Oda, K. Sone, Y. Aoki, T. Hoshida, and J. C. Rasmussen, “Demonstration of integrated optical path monitoring sub-system in CDCG-ROADM network,” in 2014 European Conference on Optical Communication (IEEE, 2014), P.4.1.
[Crossref]

Roelens, M. A.

Sakamaki, Y.

Y. Sakamaki, T. Kawai, T. Komukai, M. Fukutoku, and T. Kataoka, “Evaluation of optical filtering penalty in digital coherent detection system,” IEICE Commun. Express 1(2), 54–59 (2012).

Savory, S. J.

S. J. Savory, “Digital coherent optical receivers: algorithms and subsystems,” IEEE J. Sel. Top. Quantum Electron. 16(5), 1164–1179 (2010).
[Crossref]

Skafidas, E.

Sone, K.

G. Nakagawa, S. Oda, K. Sone, Y. Aoki, T. Hoshida, and J. C. Rasmussen, “Demonstration of integrated optical path monitoring sub-system in CDCG-ROADM network,” in 2014 European Conference on Optical Communication (IEEE, 2014), P.4.1.
[Crossref]

Stewart, L. A.

Sui, Q.

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

Q. Sui, A. P. T. Lau, and C. Lu, “Fast and robust blind chromatic dispersion estimation using auto-correlation of signal power waveform for digital coherent systems,” J. Lightwave Technol. 31(2), 306–312 (2013).
[Crossref]

Tran, A. V.

C. C. Do, C. Zhu, and A. V. Tran, “Data-aided OSNR estimation using low-bandwidth coherent receivers,” IEEE Photon. Technol. Lett. 26(13), 1291–1294 (2014).
[Crossref]

C. Zhu, A. V. Tran, S. Chen, L. B. Du, C. C. Do, T. Anderson, A. J. Lowery, and E. Skafidas, “Statistical moments-based OSNR monitoring for coherent optical systems,” Opt. Express 20(16), 17711–17721 (2012).
[Crossref] [PubMed]

Wang, D.

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

Xu, X.

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

Zhu, C.

C. C. Do, C. Zhu, and A. V. Tran, “Data-aided OSNR estimation using low-bandwidth coherent receivers,” IEEE Photon. Technol. Lett. 26(13), 1291–1294 (2014).
[Crossref]

C. Zhu, A. V. Tran, S. Chen, L. B. Du, C. C. Do, T. Anderson, A. J. Lowery, and E. Skafidas, “Statistical moments-based OSNR monitoring for coherent optical systems,” Opt. Express 20(16), 17711–17721 (2012).
[Crossref] [PubMed]

Zhuge, Q.

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

IEEE J. Sel. Top. Quantum Electron. (1)

S. J. Savory, “Digital coherent optical receivers: algorithms and subsystems,” IEEE J. Sel. Top. Quantum Electron. 16(5), 1164–1179 (2010).
[Crossref]

IEEE Photon. Technol. Lett. (2)

C. C. Do, C. Zhu, and A. V. Tran, “Data-aided OSNR estimation using low-bandwidth coherent receivers,” IEEE Photon. Technol. Lett. 26(13), 1291–1294 (2014).
[Crossref]

X. Liu, Y. H. Kao, S. Chandrasekhar, I. Kang, S. Cabot, and L. L. Buhl, “OSNR monitoring method for OOK and DPSK based on optical delay interferometer,” IEEE Photon. Technol. Lett. 19(15), 1172–1174 (2007).
[Crossref]

IEEE Photonics J. (1)

M. S. Faruk, Y. Mori, and K. Kikuchi, “In-Band estimation of optical signal-to-noise ratio from equalized signals in digital coherent receivers,” IEEE Photonics J. 6(1), 7800109 (2014).
[Crossref]

IEEE Signal Process. Mag. (1)

A. P. T. Lau, Y. Gao, Q. Sui, D. Wang, Q. Zhuge, M. Morsy-Osman, M. Chagnon, X. Xu, C. Lu, and D. V. Plant, “Advanced DSP techniques enabling high spectral efficiency and flexible transmissions: toward elastic optical networks,” IEEE Signal Process. Mag. 31(2), 82–92 (2014).
[Crossref]

IEICE Commun. Express (1)

Y. Sakamaki, T. Kawai, T. Komukai, M. Fukutoku, and T. Kataoka, “Evaluation of optical filtering penalty in digital coherent detection system,” IEICE Commun. Express 1(2), 54–59 (2012).

J. Lightwave Technol. (1)

Opt. Express (3)

Other (7)

Z. Dong, Q. Sui, A. P. T. Lau, K. Zhong, L. Li, Z. Li, and C. Lu, “Optical performance monitoring in DSP-based coherent optical systems,” in Proc. Opt. Fiber Commun. (OFC), Los Angeles, CA, Mar. 2015, Paper W4D.1.

D. J. Ives, B. C. Thomsen, R. Maher, and S. J. Savory, “Estimating OSNR of equalised QPSK signals,” in Proc. Eur. Conf. Exhib. Opt. Commun. (ECOC), Geneva, Switzerland, Sep. 2011, Paper Tu.6.A.6.

S. Oda, J. Y. Yang, Y. Akasaka, K. Sone, Y. Aoki, M. Sekiya, and J. C. Rasmussen, “In-band OSNR monitor using an optical bandpass filter and optical power measurements for superchannel signals,” in Proc. Eur. Conf. Exhib. Opt. Commun. (ECOC), London, U. K., Sep. 2013, paper P.3.12.
[Crossref]

G. Nakagawa, S. Oda, K. Sone, Y. Aoki, T. Hoshida, and J. C. Rasmussen, “Demonstration of integrated optical path monitoring sub-system in CDCG-ROADM network,” in 2014 European Conference on Optical Communication (IEEE, 2014), P.4.1.
[Crossref]

Optical Monitoring for DWDM Systems. ITU-T recommendation G.697, June 2004.

H. Rosenfeldt, I. Clarke, S. Frisken, G. Dash, X. Huang, H. Li, W. Cui, J. Zhang, J. Chen, Z. Kong, and S. Poole, “Miniaturized heterodyne channel monitor with tone detection,” in Optical Fiber Communication Conference, OSA Technical Digest (online) (Optical Society of America, 2015), paper W4D.7.
[Crossref]

VPIsystemsTM, “VPltransmission MakerTM”.

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 (11)

Fig. 1
Fig. 1 (a) Schematic diagram of proposed OSNR monitor; (b) Signal spectra before and after coherent receptions; RF spectrum after electrical filtering showing filtered signal (marked in green) and ASE noise (marked in red), whereas PCF, POF1 and POF2 denote RF power after electrical filtering when the LO frequency is set to the center frequency of the spectrum fCF and two other offset frequencies fOF1 and fOF2, (c) WSS filtering induced optical spectral narrowing and RF spectral narrowing. ROADM: reconfigurable optical add-drop multiplexer, EDFA: erbium-doped fiber amplifier, OPM: optical performance monitor, Rx: receiver. ASE: amplified spontaneous emission.
Fig. 2
Fig. 2 Experimental setup. Att: attenuator, AWG: arbitrary waveform generator, AOM: acousto-optic modulator, ECL: external cavity laser, PBS: polarization beam splitter, PBC: polarizing beam combiner, PC: polarization controller, SSMF: standard single-mode fiber.
Fig. 3
Fig. 3 Amplitude spectrum of the programmable WSS with 5th-order super-Gaussian transfer function for the channel of interest and all-pass shapes for the two neighboring channels.
Fig. 4
Fig. 4 Experimental OSNR monitoring error versus actual OSNR for DP-64-QAM signals transmitted over 640 km using an electrical filter with bandwidth from 500 MHz to 8GHz.
Fig. 5
Fig. 5 Experimental OSNR monitoring error versus actual OSNR for DP-64-QAM signals transmitted over 640 km using various sets of offset frequency fOF1 and fOF2.
Fig. 6
Fig. 6 Experimental OSNR monitoring error versus actual OSNR for DP-QPSK/16-QAM /64-QAM signals over various transmission distances (different number of WSSs). All the monitoring errors are less than 0.7 dB by using Eq. (4). The results showed in pink curve are the monitoring errors for DP-64-QAM signals after 640 km transmission obtained by using Eq. (2) when WSS filtering is not taken into account.
Fig. 7
Fig. 7 Experimental OSNR monitoring error versus actual OSNR for DP-64-QAM signals transmitted over 640 km in the presence of different frequency offsets up to 1 GHz between the lasers of transmitter and receiver.
Fig. 8
Fig. 8 Simulated OSNR monitoring error versus actual OSNR for DP-16-QAM and DP-64-QAM signals transmitted over 640 km of different channels in a WDM system at different launched power per channel.
Fig. 9
Fig. 9 Simulated OSNR monitoring error versus actual OSNR for DP-16-QAM and DP-64-QAM signals transmitted over 640 km of different channels in a WDM system using LO with 1-MHz and 5-MHz linewidth.
Fig. 10
Fig. 10 Simulated OSNR monitoring error versus actual OSNR for DP-QPSK signals transmitted over 800 km under different degrees of calibration parameter mismatches.
Fig. 11
Fig. 11 OSNR monitoring error versus actual OSNR for DP-QPSK signals transmitted over 800 km with non-identical cascaded WSSs.

Equations (4)

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

P CF = P SIG + P ASE , P OF1 = R 1 P SIG + P ASE .
OSNR=γ P SIG P ASE =γ 1- P CF / P OF1 ( P CF / P OF1 ) R 1 -1 ,
P CF = P SIG + P ASE , P OF1 = R 1 α N P SIG + P ASE , P OF2 = R 2 β N P SIG + P ASE .
P OF1 P CF R 1 + P OF1 / P CF 1 R 1 OSNR = ( P OF2 P CF R 2 + P OF2 / P CF 1 R 2 OSNR ) logα / logβ .

Metrics