OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 15, Iss. 1 — Jan. 8, 2007
  • pp: 56–61
« Show journal navigation

Polarization-interleaved WDM signals in a fiber optical parametric amplifier with orthogonal pumps

K. K. Y. Wong, Guo-Wei Lu, and Lian-Kuan Chen  »View Author Affiliations


Optics Express, Vol. 15, Issue 1, pp. 56-61 (2007)
http://dx.doi.org/10.1364/OE.15.000056


View Full Text Article

Acrobat PDF (312 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

We have demonstrated a polarization-interleaved wavelength-division multiplexed system with a two-orthogonal-pump optical parametric amplifier. The sensitivity has been improved by about 2dB compared to its counterpart with all channels co-polarized, with the same signal gain, which itself dramatically improved over the conventional two-parallel-pump OPA.

© 2007 Optical Society of America

1. Introduction

In this paper, we further demonstrate that with the aid of polarization interleaving (POIN) [20

20. S. G. Evangelides Jr., L. F. Mollenauer, J. P. Gordon, and N. S. Bergano, “Polarization multiplexing with solitons,” J. Lightwave Technol. ,10, pp.28–35 (1992). [CrossRef]

], the WDM signal degradation can be improved significantly. That is because FWM is strongly dependent on the states of polarization (SOPs) of neighboring channels and is essentially suppressed if two channels are orthogonal to each other [21

21. K. Inoue, “Polarization effect on four-wave mixing efficiency in a single-mode fiber,” IEEE J. of Quantum. Elect. ,28,883–894 (1992). [CrossRef]

]. We will focus on the large-signal behavior in 2P-OPA, particularly 2OP-OPA.

2. Theory

The signal quality degradation of WDM channels due to XGM and FWM in a 2P-OPA system is illustrated in Fig. 1. Only channel #1 (λ 1) is shown with intensity-modulation (IM) for clarity. Also note that the corresponding idlers for all four channels (λ 1 - λ 4) have not been shown here for simplicity. The signal (λ 1) is amplified by the parametric gain (with pump wavelengths at λ p1 and λ p2). As it grows, it draws power away from the pump(s), because the total optical power remains constant. As a result, the pump power itself now has IM and all channels #2 – #4 will exhibit slightly different gains at different times, depending on whether they travel with a depleted part of the pump, or an undepleted one. As a result, the amplified channels #2 – #4 will themselves exhibit IM, which constitutes crosstalk. If we now consider that channels #2 – #4 are replaced by independent modulation signals, it is clear that their amplitudes will experience fluctuations due to XGM crosstalk induced by the first channel and vice versa, which will lead to deterioration of their qualities. Furthermore, the spurious FWM also lead to extra signal quality degradation [11

11. S. Radic, C. J. McKinstrie, R. M. Jopson, J. C. Centanni, Q. Lin, and G. P. Agrawal, “Record performance of parametric amplifier constructed with highly nonlinear fibre,” IEE Elect. Lett. ,39,838–839 (2003). [CrossRef]

].

Fig. 1. Illustration of the signal quality degradation of WDM system due to XGM and FWM effects in a 2P-OPA configuration. Refer to the text for details.

Previously, we have demonstrated with co-polarized (COPO) WDM channels in a 2OP-OPA [as shown in Fig. 2(a)], that the WDM signal degradation improved by at least 1.7 dB in the Q-factor measurement, and by more than 2 dB in the power penalty, compared to the 2PP-OPA counterpart. Now, we propose that by using POIN WDM channels [as shown in Fig. 2 (b)], the signal quality can further be improved.

Fig. 2. 2OP-OPA system with WDM channels that are: (a) Co-polarized (COPO); (b) Polarization-interleaved (POIN).

3. Experiments

Fig. 3. 2OP-OPA with POIN configuration. TLS: Tunable laser source. PC: Polarization controller. PM: Phase modulator. VOA: variable optical attenuator. MZ-IM: Mach-Zehner intensity modulator. ISO: Isolator.

4. Results and discussion

Fig. 4. Optical spectra for 2OP-OPA with three POIN WDM channels.
Fig. 5. Eye diagrams (with Q factors) for 2OP-OPA with COPO signals at different λs (nm): (a) 1551.1; (b) 1551.9; (c) 1552.7; (d) 1553.5. The corresponding eye diagrams with POIN signals (e) – (h).

The results are shown in Fig. 4, Fig. 5, and Fig. 6. Firstly, Fig. 4 shows the output optical spectrum with channels #1, #3 and #4 turned ON, while channel #2 was OFF. Since the noise floor at channel #2 (1551.9 nm) is about -20dB below channel #1 (1551.1 nm), the FWM crosstalk is at least -20dB, which is marginally better than that measured in a 2OP-OPA with COPO signals (i.e. -19.4dB) [19

19. K. K. Y. Wong, G.-W. Lu, M. E. Marhic, and L.-K. Chen, “Experimental reduction of WDM signal crosstalk in fiber optical parametric amplifiers by using orthogonal pumps,” in Proc. European Conf. on Opt. Comm. , vol.3, Sept. 2005, paper We4.P.136.

]. It cannot provide conclusive evidence of the improvement of 2OP-OPA with POIN over COPO signals.

Therefore, we measured the eye diagrams and Q-factors for all four channels (including channel #2, which was OFF in Fig. 4) and the results are shown in Fig. 5(a) – (h). The eye diagrams for 2OP-OPA with POIN signals have wider eye openings than those with COPO signals, as shown in Fig. 5(a) – (h). Also the Q factor is improved by at least 3dB. Note that the increase of the crosspoint is due to the OPA gain saturation. We take advantage of it to suppress the noise in the mark level.

Fig. 6 BER curves for all four channels with POIN and COPO signals.

In order to quantify the power penalty due to the OPA, we also measured the BER of the amplified signal for 2OP-OPA with POIN and COPO signals. The results are shown in Fig. 6. Note that there is about a 2dB improvement in sensitivity of POIN over COPO signals, which is consistent with what we inferred from Fig. 5. The power penalty over the back-to-back curve is due to the imperfect SBS suppression and the ASE noise inherited from the high power EDFA.

The common parameters used here were the same as in our experiments, namely: Fiber: HNL-DSF; L = 2 km; γ = 10.4 W-1 km-1; λ 0 = 1543.4 nm; dispersion slope of 0.019 ps/nm2km. When four WDM channels were present at the same set of wavelengths as in our experiments, the simulation results showed a FWM crosstalk reduction by at least 7dB as the channel separation was increased from 100GHz to 400GHz. This helps to justify limiting our experiments to only four WDM wavelengths, 100GHz apart.

We also extended the system to 32 WDM channels, and similar simulation results were obtained. POIN performed better than COPO by at least 1.5 dB in term of Q-factor for most of the WDM channels, especially those channels with poorer Q-factors.

The rationale for the experiments is based on the FWM reduction due to POIN signals. However, there is no similar expectation for XGM. In fact, since in a polarization-independent OPA the gain is the same regardless of SOP, so should be the pump depletion, and the XGM. Therefore, we conclude that the improvement is due to the suppressed spurious FWM in the POIN over COPO configurations.

5. Conclusion

We have demonstrated, for the first time to our knowledge, a polarization-interleaved WDM system with a two-orthogonal-pump OPA. The sensitivity has been improved by about 2dB compared to its counterpart with all co-polarized WDM channels with the same signal gain. These results should help design high-performance OPAs for use in WDM communication systems.

Acknowledgment

The work described in this paper was partially support by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. HKU 7179/06E). Thanks are also due to M. E. Marhic for interesting discussions.

References and Links

1.

K. K. Y. Wong, K. Shimizu, K. Uesaka, G. Kalogerakis, M. E. Marhic, and L. G. Kazovsky, “Continuous-wave fiber optical parametric amplifier with 60 dB gain using a novel two-segment design,” IEEE Photon. Technol. Lett. ,15,1707–1709 (2003). [CrossRef]

2.

M. E. Marhic, K. K. Y. Wong, and L. G. Kazovsky, “Wideband Tuning of the Gain Spectra of One-Pump Fiber Optical Parametric Amplifiers,” IEEE J. on Selected Topics in Quantum Electronics ,10,1133–1141 (2004). [CrossRef]

3.

K. K. Y. Wong, M. E. Marhic, K. Uesaka, and L. G. Kazovsky, “Polarization-Independent Two-Pump Fiber Optical Parametric Amplifier,” IEEE Photon. Technol. Lett. ,14,911–913 (2002). [CrossRef]

4.

R. Jopson and R. E. Tench, “Polarisation-independent phase conjugation of lightwave signals,” IEE Elect. Lett. ,29,2216–2217 (1993). [CrossRef]

5.

K. Inoue, “Polarization independent wavelength conversion using fiber four-wave mixing with two orthogonal pump lights of different frequencies,” J. Lightwave Technol. ,12,1916–1920 (1994). [CrossRef]

6.

M. E. Marhic, G. Kalogerakis, K. K. Y. Wong, and L. G. Kazovsky, “Pump-to-signal transfer of low-frequency intensity modulation in fiber optical parametric amplifiers,” J. Lightwave Technol. ,23,1049–1055 (2005). [CrossRef]

7.

G. Kalogerakis, M. E. Marhic, and L. G. Kazovsky, “Signal-Signal Cross-Phase Modulation in Fiber OPAs,” 15D1-3 in Optoelectronics and Comm. Conf., Kanagawa, Japan, Jul. 2004.

8.

T. H. Torounidis, H. Sunnerud, P. O. Hedekvist, and P. A. Andrekson, “Amplification of WDM signals in fiber-based optical parametric amplifiers,” IEEE Photon. Technol. Lett. ,15,1061–1063 (2003). [CrossRef]

9.

F. Forghieri, R. W. Tkach, A. R. Chraplyvy, and D. Marcuse, “Reduction of four-wave mixing crosstalk in WDM systems using unequally spaced channels,” IEEE Photon. Technol. Lett. ,6,754–756 (1994). [CrossRef]

10.

M. E. Marhic, Y. Park, F. S. Yang, and L. G. Kazovsky, “Broadband fiber-optical parametric amplifiers and wavelength converters with low-ripple Chebyshev gain spectra,” Opt. Lett. ,21,1354–1356 (1996). [CrossRef] [PubMed]

11.

S. Radic, C. J. McKinstrie, R. M. Jopson, J. C. Centanni, Q. Lin, and G. P. Agrawal, “Record performance of parametric amplifier constructed with highly nonlinear fibre,” IEE Elect. Lett. ,39,838–839 (2003). [CrossRef]

12.

J. M. Chavez Boggio, J. D. Marconi, and H. L. Fragnito, “Double-Pumped Fiber Optical Parametric Amplifier With Flat Gain Over 47-nm Bandwidth Using a Conventional Dispersion-Shifted Fiber,” IEEE Photon. Technol. Lett. ,17,1842–1844 (2005). [CrossRef]

13.

F. A. Callegari, J. M. Chavez Boggio, and H. L. Fragnito, “Spurious Four-Wave Mixing in Two-Pump Fiber-Optic Parametric Amplfiers,” IEEE Photon. Technol. Lett. ,16,434–436 (2004). [CrossRef]

14.

J. D. Marconi, J. M. Chavez Boggio, and H. L. Fragnito, “Crosstalk in double-pumped fiber optic parametric amplifiers for wavelength division multiplexing systems,” Opt. Comm. ,259,94–103 (2006). [CrossRef]

15.

J. L. Blows and P. -F. Hu, “Cross-talk-induced limitations of two-pump optical fiber parametric amplifiers,” J. of Opt. Soc. Of Amer. B. ,21,989–995 (2004). [CrossRef]

16.

J. L. Blows, “Design strategy for controlling four-wave mixing-induced crosstalk between channels in a fibre optical parametric amplifier,” Opt. Comm. ,236,115–122 (2004). [CrossRef]

17.

S. Radic, R. Jopson, C. McKinstrie, A. Gnauck, S. Chandrasekhar, and J. C. Centanni, “Wavelength division multiplexed transmission over standard single mode fiber using polarization insensitive signal conjugation in highly nonlinear optical fiber,” in Proc. Optical Fiber Communications Conf., vol.3, Mar. 2003, PD12.

18.

P. -F. Hu and J. L. Blows, “Four-wave mixing crosstalk in optical fibre parametric amplifiers with orthogonal pumps,” Opt. Comm. ,250,421–427 (2005). [CrossRef]

19.

K. K. Y. Wong, G.-W. Lu, M. E. Marhic, and L.-K. Chen, “Experimental reduction of WDM signal crosstalk in fiber optical parametric amplifiers by using orthogonal pumps,” in Proc. European Conf. on Opt. Comm. , vol.3, Sept. 2005, paper We4.P.136.

20.

S. G. Evangelides Jr., L. F. Mollenauer, J. P. Gordon, and N. S. Bergano, “Polarization multiplexing with solitons,” J. Lightwave Technol. ,10, pp.28–35 (1992). [CrossRef]

21.

K. Inoue, “Polarization effect on four-wave mixing efficiency in a single-mode fiber,” IEEE J. of Quantum. Elect. ,28,883–894 (1992). [CrossRef]

22.

A. Carena, V. Curri, R. Gaudino, P. Poggiolini, and S. Benedetto,OptSim, distributed by RSoft (http://www.rsoftdesign.com). “Time-domain optical transmission system simulation package accounting for nonlinear and polarization-related effects in fiber,” IEEE J. Sel. Areas in Comm. ,15,751–765 (1997). [CrossRef]

OCIS Codes
(060.2320) Fiber optics and optical communications : Fiber optics amplifiers and oscillators
(060.2330) Fiber optics and optical communications : Fiber optics communications
(190.4370) Nonlinear optics : Nonlinear optics, fibers

ToC Category:
Fiber Optics and Optical Communications

History
Original Manuscript: September 26, 2006
Revised Manuscript: November 20, 2006
Manuscript Accepted: December 19, 2006
Published: January 8, 2007

Citation
K. K. Y. Wong, Guo-Wei Lu, and Lian-Kuan Chen, "Polarization-interleaved WDM signals in a fiber optical parametric amplifier with orthogonal pumps," Opt. Express 15, 56-61 (2007)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-15-1-56


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. K. K. Y. Wong, K. Shimizu, K. Uesaka, G. Kalogerakis, M. E. Marhic, and L. G. Kazovsky, "Continuous-wave fiber optical parametric amplifier with 60 dB gain using a novel two-segment design," IEEE Photon. Technol. Lett.,  15, 1707−1709 (2003). [CrossRef]
  2. M. E. Marhic, K. K. Y. Wong, and L. G. Kazovsky, "Wideband Tuning of the Gain Spectra of One-Pump Fiber Optical Parametric Amplifiers," IEEE J. on Selected Topics in Quantum Electronics, 10, 1133−1141 (2004). [CrossRef]
  3. K. K. Y. Wong, M. E. Marhic, K. Uesaka, and L. G. Kazovsky, "Polarization-Independent Two-Pump Fiber Optical Parametric Amplifier," IEEE Photon. Technol. Lett.,  14, 911−913 (2002). [CrossRef]
  4. R. Jopson and R. E. Tench, "Polarisation-independent phase conjugation of lightwave signals," IEE Elect. Lett.,  29, 2216-2217 (1993). [CrossRef]
  5. K. Inoue, "Polarization independent wavelength conversion using fiber four-wave mixing with two orthogonal pump lights of different frequencies," J. Lightwave Technol.,  12, 1916-1920 (1994). [CrossRef]
  6. M. E. Marhic, G. Kalogerakis, K. K. Y. Wong, and L. G. Kazovsky, "Pump-to-signal transfer of low-frequency intensity modulation in fiber optical parametric amplifiers," J. Lightwave Technol.,  23,1049−1055 (2005). [CrossRef]
  7. <conf>. G. Kalogerakis, M. E. Marhic, and L. G. Kazovsky, "Signal-Signal Cross-Phase Modulation in Fiber OPAs," 15D1-3 in Optoelectronics and Comm. Conf., Kanagawa, Japan, Jul. 2004.</conf>
  8. T. H. Torounidis, H. Sunnerud, P. O. Hedekvist, and P. A. Andrekson, "Amplification of WDM signals in fiber-based optical parametric amplifiers," IEEE Photon. Technol. Lett.,  15, 1061-1063 (2003). [CrossRef]
  9. F. Forghieri, R. W. Tkach, A. R. Chraplyvy, and D. Marcuse, "Reduction of four-wave mixing crosstalk in WDM systems using unequally spaced channels," IEEE Photon. Technol. Lett.,  6, 754-756 (1994). [CrossRef]
  10. M. E. Marhic, Y. Park, F. S. Yang, and L. G. Kazovsky, "Broadband fiber-optical parametric amplifiers and wavelength converters with low-ripple Chebyshev gain spectra," Opt. Lett.,  21, 1354-1356 (1996). [CrossRef] [PubMed]
  11. S. Radic, C. J. McKinstrie, R. M. Jopson, J. C. Centanni, Q. Lin, and G. P. Agrawal, "Record performance of parametric amplifier constructed with highly nonlinear fibre," IEE Elect. Lett.,  39, 838-839 (2003). [CrossRef]
  12. J. M. Chavez Boggio, J. D. Marconi, and H. L. Fragnito, "Double-Pumped Fiber Optical Parametric Amplifier With Flat Gain Over 47-nm Bandwidth Using a Conventional Dispersion-Shifted Fiber," IEEE Photon. Technol. Lett.,  17, 1842-1844 (2005). [CrossRef]
  13. F. A. Callegari, J. M. Chavez Boggio, and H. L. Fragnito, "Spurious Four-Wave Mixing in Two-Pump Fiber-Optic Parametric Amplfiers," IEEE Photon. Technol. Lett.,  16, 434-436 (2004). [CrossRef]
  14. J. D. Marconi, J. M. Chavez Boggio, and H. L. Fragnito, "Crosstalk in double-pumped fiber optic parametric amplifiers for wavelength division multiplexing systems," Opt. Comm., 259, 94−103 (2006). [CrossRef]
  15. J. L. Blows and P. -F. Hu, "Cross-talk-induced limitations of two-pump optical fiber parametric amplifiers," J. of Opt. Soc. Of Amer. B., 21, 989−995 (2004). [CrossRef]
  16. J. L. Blows, "Design strategy for controlling four-wave mixing-induced crosstalk between channels in a fibre optical parametric amplifier," Opt. Comm., 236, 115−122 (2004). [CrossRef]
  17. S. Radic, R. Jopson, C. McKinstrie, A. Gnauck, S. Chandrasekhar, and J. C. Centanni, "Wavelength division multiplexed transmission over standard single mode fiber using polarization insensitive signal conjugation in highly nonlinear optical fiber," in Proc. Optical Fiber Communications Conf., vol. 3, Mar. 2003, PD12.
  18. P. -F. Hu and J. L. Blows, "Four-wave mixing crosstalk in optical fibre parametric amplifiers with orthogonal pumps," Opt. Comm., 250, 421−427 (2005). [CrossRef]
  19. K. K. Y. Wong, G.-W. Lu, M. E. Marhic, and L.-K. Chen, "Experimental reduction of WDM signal crosstalk in fiber optical parametric amplifiers by using orthogonal pumps," in Proc. European Conf. on Opt. Comm., vol. 3, Sept. 2005, paper We4.P.136.
  20. S. G. EvangelidesJr., L. F. Mollenauer, J. P. Gordon, N. S. Bergano, "Polarization multiplexing with solitons," J. Lightwave Technol.,  10, pp. 28-35 (1992). [CrossRef]
  21. K. Inoue, "Polarization effect on four-wave mixing efficiency in a single-mode fiber," IEEE J. of Quantum. Elect., 28, 883-894 (1992). [CrossRef]
  22. OptSim, distributed by RSoft (http://www.rsoftdesign.com). A. Carena, V. Curri, R. Gaudino, P. Poggiolini, and S. Benedetto, "Time-domain optical transmission system simulation package accounting for nonlinear and polarization-related effects in fiber," IEEE J. Sel. Areas in Comm., 15, 751-765 (1997). [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