OSA's Digital Library

Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 22, Iss. 6 — Mar. 24, 2014
  • pp: 6925–6933
« Show journal navigation

Power budget improvement of symmetric 40-Gb/s DML-based TWDM-PON system

Meihua Bi, Shilin Xiao, Lilin Yi, Hao He, Jun Li, Xuelin Yang, and Weisheng Hu  »View Author Affiliations


Optics Express, Vol. 22, Issue 6, pp. 6925-6933 (2014)
http://dx.doi.org/10.1364/OE.22.006925


View Full Text Article

Acrobat PDF (1907 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

We propose a symmetric 40-Gb/s time and wavelength division multiplexed passive optical network (TWDM-PON) system with directly modulated laser (DML) as both downstream and upstream transmitters. A single bi-pass delay interferometer (DI), deployed in the optical line terminal (OLT), is used to mitigate multiple channels’ signal distortions induced by laser chirp and fiber chromatic dispersion. With the help of the DI, we successfully demonstrate error-free transmission with the aggregate capacity of 40 Gb/s over different transmission distance. And in back-to-back case, by using a 0.2-nm free spectrum range (FSR) DI, ~11 dB optical power budget improvement is achieved at a bit error ratio of 1e-3. Owing to this high power budget, the maximum reach can be extended to 50 km for 1024 splits, 75 km for 256 splits, and 100 km for 64 splits. Meanwhile, the impacts of FSR of DI and laser wavelength shift on system performance are investigated in terms of receiver sensitivity. It is shown that, our system can achieve more than 43-dB power budget and support ± 2.5-GHz wavelength shift when the FSR is less than 0.2 nm.

© 2014 Optical Society of America

1. Introduction

In this paper, we propose a symmetric 40-Gb/s TWDM-PON system employing low-cost DML as both upstream and downstream transmitters and a single bi-pass DI deployed in the optical line terminal (OLT) to mitigate the distortions of multiple bidirectional wavelength channels. With the help of DI, this scheme enhances the capabilities of system transmission distance and greatly improves OPB. The feasibility of proposed system is experimentally verified with different free-spectral range (FSR) of DI. Results show that, the system power budget depends on the FSR of DI and this system can support wide range of fiber transmission no matter the signal is severely or slightly distorted. Meanwhile, the system without repeater achieves 1:1024, 1:256 and 1:64 splitting ratio over 50 km, 75 km and 100 km fiber transmission respectively.

2. System architecture and experimental setup

In each ONU, the downstream signals pass through a TOF with 0.8-nm bandwidth before being detected by an avalanche photo diode (APD). As for uplink, the DFB biased at 65mA has ~9-dBm stable output power with tunable wavelength range of ~3.0 nm, thus each ONU can be tuned among four wavelength channels with 0.8-nm spacing. After the power coupling and fiber transmission, the upstream signals are firstly injected into the bi-directional EDFA for pre-amplification and then into the DI for suppressing the distortion caused by the frequency chirp and dispersion. The filtered signals after DI are then fed into AWG and received by APD for upstream performance evaluation. It is worth noting that, since the specific wavelength plan standard for NG-PON2 is not ultimately defined yet and using the C-band wavelength can easily facilitate the co-existence with legacy PONs (GPON, XG-PON, and 10GEPON) [7

7. Y. Luo, X. Zhou, F. Effenberger, X. Yan, G. Peng, Y. Qian, and Y. Ma, “Time and Wavelength Division Multiplexed Passive Optical Network (TWDM-PON) for Next Generation PON Stage 2 (NG-PON2),” J. Lightwave Technol. 31(4), 587–593 (2013). [CrossRef]

,13

13. E. Wong, M. Mueller, and M. C. Amann, “Characterization of energy-efficient and colorless ONUs for future TWDM-PONs,” Opt. Express 21(18), 20747–20761 (2013). [CrossRef] [PubMed]

], thus the upstream wavelengths in our experiment are set at 1541.71 nm, 1542.51 nm, 1543.31 nm and 1544.11 nm.

3. Experimental results

The spectra of both downstream and upstream signals over 25-km SMF transmission with and without DI, and the transmittance curve of DI are shown in Fig. 2
Fig. 2 optical spectrum of signal for 25-km SMF without and with the 0.2-nm FSR DI, and the DI transmittance spectrum in (a) downstream, (b) upstream.
. Here, we use the DI with 0.2-nm FSR for simultaneous multi-channels operation with 0.8-nm spacing, and similar results can be achieved under other FSRs. By controlling the thermoelectric cooler (TEC) modules and electrically feed-back loop, the initial phase of DI is adjusted to a suitable place so that it can provide an optimum wavelength-offset with respect to the optical carrier. As shown in Fig. 2(a), the peak wavelength of DI transmittance curve is detuned ~0.04 nm to the short wavelength from the carrier. Thus, it can filter out the red shift chirp-induced spectrum broadening low-frequency components which is corresponding to the “0”s of data sequences, and hence increasing the extinction ratio (ER) of signals. Owing to the periodical notch property of DI, the partial noise floor of DML is also filtered out, therefore improving the signal to noise ratio.

The upstream BER and electrical eye diagrams with different fiber length are shown in Fig. 4(b). In comparison with the BtB case excluding DI, the receiver sensitivities at BER = 1e-3 are improved by ~11 dB, ~10.8 dB, ~9.6 dB and ~9 dB for 25 km, 50 km, 75 km and 100 km SMF transmission respectively, which results in significant OPB improvement. A little power penalty difference among the different distance is also observed from this figure, which can be attributed to different accumulated residual chromatic dispersion effect. In addition, it should be noted that, this DI-based scheme can be acted as a tunable dispersion compensator rather than a fixed dispersion one, and can support continuous length repeater-less fiber transmission. Thereby, it can be considered as a flexible and promising method for reducing the impacting of chirp on the DML-based TWDM-PON system. Meanwhile, due to the chirp properties of DML [16

16. J. L. Wei, C. Sánchez, R. P. Giddings, E. Hugues-Salas, and J. M. Tang, “Wavelength-Offset Filtering in Optical OFDM IMDD Systems Using Directly Modulated DFB Lasers,” J. Lightwave Technol. 29(18), 2861–2870 (2011). [CrossRef]

18

18. B. Wedding, B. Franz, and B. Junginger, “10-Gb/s optical transmission up to 253 km via standard single-mode fiber using the method of dispersion-supported transmission,” J. Lightwave Technol. 12(10), 1720–1727 (1994). [CrossRef]

] and the periodical features of bi-pass DI, our scheme can support various data rate TWDM-PON system, and the corresponding work need to be further investigated.

4. Further discussion

To investigate the impact of the FSR of DI on TWDM-PON system, we use a DI with tunable FSR. Figure 5
Fig. 5 measured upstream sensitivity at BER = 1e-3 versus the fiber length with the different FSR of DI, the insets (i) the DI transmission spectrum with different FSR.
shows the upstream sensitivity at BER = 1e-3 with the worst case among four channels for different fiber length without and with DI. It is shown that, for the excluding DI case, the sensitivity firstly degrades at 25-km SMF, then becomes better with the increase of fiber distance, and it is even up to ~-29 dBm over 75-km SMF. These results can be explained as the dispersion-supported transmission (DST) caused by the interaction of chirp with fiber dispersion [18

18. B. Wedding, B. Franz, and B. Junginger, “10-Gb/s optical transmission up to 253 km via standard single-mode fiber using the method of dispersion-supported transmission,” J. Lightwave Technol. 12(10), 1720–1727 (1994). [CrossRef]

]. Using the DI, it is evidence that the sensitivity is improved with different FSRs. Meanwhile, no matter what fiber length is, the sensitivity always decreases with the increase of FSR. The reason is explained as follows. From observations in the inset (i) of Fig. 5, as the FSR increases, the slope of DI transmission spectrum is not steep, leading to a poor spectral reshaping. It should be pointed out that, when the 0.1-nm and 0.2-nm FSRs are employed, almost the same performance is obtained, which means that 0.2-nm FSR DI is good enough for our system. The similar result is observed in the case of downlink.

Finally, considering the factor of the FSR of DI, we get the whole system power budget as depicted in Fig. 7
Fig. 7 Power budget of the proposed TWDM-PON system as a function of fiber length and the FSR of DI.
. It is clearly observed that, for a fixed FSR, an increasing fiber length brings in OPB reduction, resulting from the residual dispersion induced system degradation. An increasing in FSR also produces a low power budget due to the unfiltered chirp induced signal distortions. These two effects worsen the power budget and subsequently reduce the user numbers that the system can support. Thus, for a specific fiber length, a suitable FSR occurs, according to which a large power budget is observed. In addition, it can be seen in Fig. 7, for the FSR of < 0.4 nm, the minimum power budget of ~43 dB can be obtained for the fiber length of < 60 km, which supports at least 512 users. When the FSR <0.2 nm, we achieve the minimum power budget of ~43 dB over 100-km SMF and ~45 dB over 60-km SMF, which accommodate 64 users and 1024 users, respectively. From above analysis, it can be seen that the system power budget is adjustable when different FSR is adopted.

4. Conclusion

Acknowledgments

The work was jointly supported by the National Nature Science Fund of China (No. 61271216, No. 61221001, No. 61090393 and No. 60972032), the National “973” Project of China (No.2010CB328205, No. 2010CB328204 and No. 2012CB315602), China Postdoctoral Science Foundation (No. 2013M540361) and the National “863” Hi-tech Project of China.

References and links

1.

H. Nakamura, “NG-PON2 Technology,” in Proc. OFC 2013, paper NTh4F.5 (2013).

2.

D. Iida, S. Kuwano, J. Kani, and J. Terada, “Dynamic TWDM-PON for mobile radio access networks,” Opt. Express 21(22), 26209–26218 (2013). [CrossRef] [PubMed]

3.

C. W. Chow and C. H. Yeh, “Using downstream DPSK and upstream wavelength-shifted ASK for rayleigh backscattering mitigation in TDM-PON to WDM-PON migration scheme,” IEEE Photon. J. 5(2), 7900407 (2013). [CrossRef]

4.

N. Cvijetic, “OFDM for Next Generation Optical Access Networks,” J. Lightwave Technol. 30(4), 384–398 (2012). [CrossRef]

5.

S. Smolorz, E. Gottwald, H. Rohde, D. Smith, and A. Poustie, “Demonstration of a coherent UDWDM-PON with real-time processing,” in Proc. OFC, 2012, Paper PDPD4.

6.

K. Y. Cho, U. H. Hong, Y. Takushima, A. Agata, T. Sano, M. Suzuki, Y. C. Chung, C. Keun Yeong, H. Ui Hyun, Y. Takushima, A. Agata, T. Sano, M. Suzuki, and Y. C. Chung, “103-Gb/s long-reach WDM PON implemented by using directly modulated RSOAs,” IEEE Photon. Technol. Lett. 24(3), 209–211 (2012). [CrossRef]

7.

Y. Luo, X. Zhou, F. Effenberger, X. Yan, G. Peng, Y. Qian, and Y. Ma, “Time and Wavelength Division Multiplexed Passive Optical Network (TWDM-PON) for Next Generation PON Stage 2 (NG-PON2),” J. Lightwave Technol. 31(4), 587–593 (2013). [CrossRef]

8.

R. Murano and M. J. Cahill, “Low Cost Tunable Receivers for Wavelength Agile PONs,” in Proc. ECOC 2012, Paper We.2.B.3.

9.

Z. Li, L. Yi, M. Bi, J. Li, H. He, X. Yang, and W. Hu, “Experimental demonstration of a symmetric 40-Gb/s TWDM-PON,” in Proc. OFC 2013, Paper NTh4F.3. [CrossRef]

10.

L. Yi, Z. Li, M. Bi, W. Wei, and W. Hu, “Symmetric 40-Gb/s TWDM-PON with 39dB Power Budget,” IEEE Photon. Technol. Lett. 25(7), 644–647 (2013). [CrossRef]

11.

P. P. Iannone, K. C. Reichmann, C. Brinton, J. Nakagawa, T. Cusick, E. M. Kimber, C. Doerr, L. L. Buhl, M. Cappuzzo, E. Y. Chen, L. Gomez, J. Johnson, A. M. Kanan, J. Lentz, Y. F. Chang, B. Palsdottir, T. Tokle, and L. Spiekman, “Bi-directionally amplified extended reach 40Gb/s CWDM-TDM PON with burst-mode upstream transmission,” in Proc. OFC 2011, Paper PDPD6. [CrossRef]

12.

Y. Ma, Y. Qian, G. Peng, X. Zhou, X. Wang, J. Yu, Y. Luo, X. Yan, and F. Effenberger, “Demonstration of a 40Gb/s time and wavelength division multiplexed passive optical network prototype system,” in proc. OFC2012, paper PDP5D.7.

13.

E. Wong, M. Mueller, and M. C. Amann, “Characterization of energy-efficient and colorless ONUs for future TWDM-PONs,” Opt. Express 21(18), 20747–20761 (2013). [CrossRef] [PubMed]

14.

E. Wong, M. Mueller, and M. C. Amann, “Colourless operation of short-cavity VCSELs in C-minus band for TWDM-PONs,” Ele. Lett. 49(4), 282–284 (2013). [CrossRef]

15.

M. Bi, S. Xiao, H. He, L. Yi, Z. Li, J. Li, X. Yang, and W. Hu, “Simultaneous DPSK demodulation and chirp management using delay interferometer in symmetric 40-Gb/s capability TWDM-PON system,” Opt. Express 21(14), 16528–16535 (2013). [CrossRef] [PubMed]

16.

J. L. Wei, C. Sánchez, R. P. Giddings, E. Hugues-Salas, and J. M. Tang, “Wavelength-Offset Filtering in Optical OFDM IMDD Systems Using Directly Modulated DFB Lasers,” J. Lightwave Technol. 29(18), 2861–2870 (2011). [CrossRef]

17.

C. R. Doerr, S. Chandrasekhar, P. J. Winzer, A. H. Gnauck, L. W. Stulz, R. Pafchek, and E. Burrows, “Simple multichannel optical equalizer mitigating intersymbol interference for 40-Gb/s nonreturn-to-zero signals,” J. Lightwave Technol. 22(1), 249–256 (2004). [CrossRef]

18.

B. Wedding, B. Franz, and B. Junginger, “10-Gb/s optical transmission up to 253 km via standard single-mode fiber using the method of dispersion-supported transmission,” J. Lightwave Technol. 12(10), 1720–1727 (1994). [CrossRef]

OCIS Codes
(060.2330) Fiber optics and optical communications : Fiber optics communications
(060.4250) Fiber optics and optical communications : Networks

ToC Category:
Optical Communications

History
Original Manuscript: November 1, 2013
Revised Manuscript: February 9, 2014
Manuscript Accepted: February 10, 2014
Published: March 18, 2014

Citation
Meihua Bi, Shilin Xiao, Lilin Yi, Hao He, Jun Li, Xuelin Yang, and Weisheng Hu, "Power budget improvement of symmetric 40-Gb/s DML-based TWDM-PON system," Opt. Express 22, 6925-6933 (2014)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-22-6-6925


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. H. Nakamura, “NG-PON2 Technology,” in Proc. OFC 2013, paper NTh4F.5 (2013).
  2. D. Iida, S. Kuwano, J. Kani, J. Terada, “Dynamic TWDM-PON for mobile radio access networks,” Opt. Express 21(22), 26209–26218 (2013). [CrossRef] [PubMed]
  3. C. W. Chow, C. H. Yeh, “Using downstream DPSK and upstream wavelength-shifted ASK for rayleigh backscattering mitigation in TDM-PON to WDM-PON migration scheme,” IEEE Photon. J. 5(2), 7900407 (2013). [CrossRef]
  4. N. Cvijetic, “OFDM for Next Generation Optical Access Networks,” J. Lightwave Technol. 30(4), 384–398 (2012). [CrossRef]
  5. S. Smolorz, E. Gottwald, H. Rohde, D. Smith, and A. Poustie, “Demonstration of a coherent UDWDM-PON with real-time processing,” in Proc. OFC, 2012, Paper PDPD4.
  6. K. Y. Cho, U. H. Hong, Y. Takushima, A. Agata, T. Sano, M. Suzuki, Y. C. Chung, C. Keun Yeong, H. Ui Hyun, Y. Takushima, A. Agata, T. Sano, M. Suzuki, Y. C. Chung, “103-Gb/s long-reach WDM PON implemented by using directly modulated RSOAs,” IEEE Photon. Technol. Lett. 24(3), 209–211 (2012). [CrossRef]
  7. Y. Luo, X. Zhou, F. Effenberger, X. Yan, G. Peng, Y. Qian, Y. Ma, “Time and Wavelength Division Multiplexed Passive Optical Network (TWDM-PON) for Next Generation PON Stage 2 (NG-PON2),” J. Lightwave Technol. 31(4), 587–593 (2013). [CrossRef]
  8. R. Murano and M. J. Cahill, “Low Cost Tunable Receivers for Wavelength Agile PONs,” in Proc. ECOC 2012, Paper We.2.B.3.
  9. Z. Li, L. Yi, M. Bi, J. Li, H. He, X. Yang, and W. Hu, “Experimental demonstration of a symmetric 40-Gb/s TWDM-PON,” in Proc. OFC 2013, Paper NTh4F.3. [CrossRef]
  10. L. Yi, Z. Li, M. Bi, W. Wei, W. Hu, “Symmetric 40-Gb/s TWDM-PON with 39dB Power Budget,” IEEE Photon. Technol. Lett. 25(7), 644–647 (2013). [CrossRef]
  11. P. P. Iannone, K. C. Reichmann, C. Brinton, J. Nakagawa, T. Cusick, E. M. Kimber, C. Doerr, L. L. Buhl, M. Cappuzzo, E. Y. Chen, L. Gomez, J. Johnson, A. M. Kanan, J. Lentz, Y. F. Chang, B. Palsdottir, T. Tokle, and L. Spiekman, “Bi-directionally amplified extended reach 40Gb/s CWDM-TDM PON with burst-mode upstream transmission,” in Proc. OFC 2011, Paper PDPD6. [CrossRef]
  12. Y. Ma, Y. Qian, G. Peng, X. Zhou, X. Wang, J. Yu, Y. Luo, X. Yan, and F. Effenberger, “Demonstration of a 40Gb/s time and wavelength division multiplexed passive optical network prototype system,” in proc. OFC2012, paper PDP5D.7.
  13. E. Wong, M. Mueller, M. C. Amann, “Characterization of energy-efficient and colorless ONUs for future TWDM-PONs,” Opt. Express 21(18), 20747–20761 (2013). [CrossRef] [PubMed]
  14. E. Wong, M. Mueller, M. C. Amann, “Colourless operation of short-cavity VCSELs in C-minus band for TWDM-PONs,” Ele. Lett. 49(4), 282–284 (2013). [CrossRef]
  15. M. Bi, S. Xiao, H. He, L. Yi, Z. Li, J. Li, X. Yang, W. Hu, “Simultaneous DPSK demodulation and chirp management using delay interferometer in symmetric 40-Gb/s capability TWDM-PON system,” Opt. Express 21(14), 16528–16535 (2013). [CrossRef] [PubMed]
  16. J. L. Wei, C. Sánchez, R. P. Giddings, E. Hugues-Salas, J. M. Tang, “Wavelength-Offset Filtering in Optical OFDM IMDD Systems Using Directly Modulated DFB Lasers,” J. Lightwave Technol. 29(18), 2861–2870 (2011). [CrossRef]
  17. C. R. Doerr, S. Chandrasekhar, P. J. Winzer, A. H. Gnauck, L. W. Stulz, R. Pafchek, E. Burrows, “Simple multichannel optical equalizer mitigating intersymbol interference for 40-Gb/s nonreturn-to-zero signals,” J. Lightwave Technol. 22(1), 249–256 (2004). [CrossRef]
  18. B. Wedding, B. Franz, B. Junginger, “10-Gb/s optical transmission up to 253 km via standard single-mode fiber using the method of dispersion-supported transmission,” J. Lightwave Technol. 12(10), 1720–1727 (1994). [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