OSA's Digital Library

Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 21, Iss. 2 — Jan. 28, 2013
  • pp: 1561–1566
« Show journal navigation

Investigating self-homodyne coherent detection in a 19 channel space-division-multiplexed transmission link

Benjamin J. Puttnam, Jun Sakaguchi, José Manuel Delgado Mendinueta, Werner Klaus, Yoshinari Awaji, Naoya Wada, Atsushi Kanno, and Tetsuya Kawanishi  »View Author Affiliations


Optics Express, Vol. 21, Issue 2, pp. 1561-1566 (2013)
http://dx.doi.org/10.1364/OE.21.001561


View Full Text Article

Acrobat PDF (995 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

We investigate the performance of a self-homodyne coherent detection (SHCD) system using a 19 core multi-core fiber (MCF) and 16 wavelength-division-multiplexed channels. We show that SHCD, with the pilot-tone transmitted on a single MCF core and information carrying signals on the remaining cores, is compatible with space-division-multiplexed transmission, potentially relaxing laser linewidth and digital signal processing requirements due to phase noise cancellation. However, inter-core crosstalk can have an impact on performance and core selection.

© 2013 OSA

1. Introduction

Self-homodyne coherent detection (SHCD) has long been proposed and investigated as a useful technique to exploit phase noise cancellation, thus reducing receiver complexity and relaxing requirements for narrow linewidth lasers and high-speed digital signal processing (DSP) [1

1. T. Miyazaki, “Linewidth-Tolerant QPSK Homodyne Transmission Using a Polarization-Multiplexed Pilot Carrier,” IEEE Photon. Technol. Lett. 18(2), 388–390 (2006). [CrossRef]

,2

2. P. Johannisson, M. Sjödin, M. Karlsson, E. Tipsuwannakul, and P. Andrekson, “Cancellation of nonlinear phase distortion in self-homodyne coherent systems,” IEEE Photon. Technol. Lett. 22(11), 802–804 (2010). [CrossRef]

]. Previously, SHCD with a pilot-tone transmitted on an orthogonal polarization to the data and used as the local oscillator (LO) signal at the receiver has been demonstrated for a range of multi-level modulation formats [3

3. M. Sjödin, E. Agrell, P. Johannisson, G.-W. Lu, P. A. Andrekson, and M. Karlsson, “Filter optimization for self-homodyne coherent WDM systems using interleaved polarization division,” J. Lightwave Technol. 29(9), 1219–1226 (2011). [CrossRef]

8

8. Y. Kamio, M. Nakamura, and T. Miyazaki, “80-Gb/s 256-QAM signals using phase noise and DGD-tolerant pilot-carrier-aided homodyne detection,” Proc. ECOC’07, P089 (2007).

], but suffers from a loss of spectral efficiency of 50% compared to polarization multiplexed systems. Although the spectral efficiency maybe improved by spectrally interleaving the pilot-tone with the signal [5

5. M. Sjödin, E. Agrell, P. Johannisson, G.-W. Lu, P. A. Andrekson, and M. Karlsson, “Interleaved polarization division multiplexing in self-homodyne coherent WDM systems,” Proc. ECOC '10, Mo.1.3.C (2010).

], recent work on space-division-multiplexing (SDM) [9

9. B. Zhu, T. F. Taunay, M. Fishteyn, X. Liu, S. Chandrasekhar, M. F. Yan, J. M. Fini, E. M. Monberg, and F. V. Dimarcello, “112-Tb/s space-division multiplexed DWDM transmission with 14-b/s/Hz aggregate spectral efficiency over a 76.8-km seven-core fiber,” Opt. Express 19(17), 16665–16671 (2011). [CrossRef] [PubMed]

12

12. B. J. Puttnam, J. Sakaguchi, W. Klaus, Y. Awaji, J.-M. Delgado Mendinueta, N. Wada, A. Kanno, and T. Kawanishi, “Investigating self-homodyne coherent detection in a 19-core spatial-division-multiplexed transmission link,” Proc. ECOC '12, Paper Tu.3.C.3 (2012).

] has opened up the possibility of employing SHCD with the pilot-tone transmitted through 1 SDM channel and the remainder used for signal channels. In an SDM system, it is envisaged that different channels experience the same environmental disturbances during transmission and thus path length variations between channels, are minimized. This is advantageous for SHCD which relies on matching the path length between pilot-tone and information channels for strong phase noise cancellation. Another advantage of utilizing SDM systems with SHCD is that the spectral efficiency cost is inversely proportional to the number of SDM channels. For example, using a 19-core fiber results in a 5.3% reduction of spectral efficiency compared to an equivalent system with intradyne detection (ID), although this figure rises to 14.3% for a 7-core fiber.

Recently, in combination with a 19-core multi-core-fiber (MCF) and free-space coupling system [10

10. W. Klaus, J. Sakaguchi, B. J. Puttnam, Y. Awaji, N. Wada, T. Kobayashi, and M. Watanabe, “Free-space coupling optics for multi-core fibers,” in Proceedings of IEEE Phot. Soc. Summer Topicals, WC3.3 (2012).

], previously used for 305-Tb/s SDM transmission [11

11. J. Sakaguchi, B. J. Puttnam, W. Klaus, Y. Awaji, N. Wada, A. Kanno, T. Kawanishi, K. Imamura, K. Inaba, K. Mukasa, R. Sugizaki, T. Kobayashi, and M. Watanabe, “19-core fiber transmission of 19×100×172-Gb/s SDM-WDM-PDM-QPSK signals at 305Tb/s,” Proc. OFC Paper PDP5C.1 (2012).

], we investigated the feasibility of combining SHCD with MCF [12

12. B. J. Puttnam, J. Sakaguchi, W. Klaus, Y. Awaji, J.-M. Delgado Mendinueta, N. Wada, A. Kanno, and T. Kawanishi, “Investigating self-homodyne coherent detection in a 19-core spatial-division-multiplexed transmission link,” Proc. ECOC '12, Paper Tu.3.C.3 (2012).

]. Here, we expand on those results with all measurements repeated and extended using an improved experimental set-up of a SHCD system with quadrature-phase-shift-keyed (QPSK) signals on 16 wavelength-division multiplexed (WDM) channels. We transmit the pilot-tone on a single core of the 19-core MCF with the remaining 18 cores used to transmit information carrying signals. We show that, in an MCF based SDM system, phase noise cancellation inherent in SHCD both relaxes the requirement for narrow linewidth lasers and can reduce the amount of DSP required at the receiver enabling cost and power savings. We investigate the transmission penalty of both SDM and WDM cases and finally assess the impact of inter-core crosstalk on system performance. We show that inter-core crosstalk must be considered as a significant, but tolerable impairment, particularly when the pilot-tone signal is transmitted on the center core, and minimizing it is advantageous for optimum performance.

2. Experiment description

The experimental set-up is shown in Fig. 1
Fig. 1 Experimental set-up for SDM-WDM self-homodyne detection measurements.
. An external-cavity tunable laser (ECTL) with 1- MHz linewidth at 193.5 THz was used for measurement signals. In WDM operation, carriers from the ECTL and 15 distributed feedback (DFB) lasers on the 100-GHz ITU grid between 192.8 THz and 194.3 THz were multiplexed together in a temperature controlled arrayed-waveguide-grating (AWG) at the input to a 3-dB coupler used to split carriers for data modulation from those to be transmitted as the pilot-tone. The additional input port of the coupler was used for an intensity modulated signal used to align the total optical path lengths traversed by the measurement signal and pilot-tone. The signal path was then amplified in an erbium-doped-fiber amplifier (EDFA) and its polarization adjusted at the input to a single polarization QPSK modulator driven by two 101-bit decorrelated 215-1 bit PRBS signals for I and Q at 5 Gbaud. The total data throughput of each 10 Gb/s channel of 16 wavelengths and 18 fiber cores was therefore 2.88 Tb/s or 2.68 Tb/s allowing a 7% overhead for forward error correction. The baud rate was intentionally kept low in order to increase the impact of phase noise in BER measurements using the ECTL. The high power arm of the 10 dB coupler was connected to The input of a 1x20 splitter which split the signal between 17 of the input fibers of the SDM MUX and subsequently in to 17 different cores of the MCF. These acted as dummy data channels and the remaining 3 ports of the splitter were used for power and spectrum monitoring. The low power output of the coupler was connected directly to the SDM MUX input of an outer core used to transmit the decorrelated signal channel upon which BER measurements were made. Variable optical attenuators (VOAs) were used on both coupler outputs to control the fiber launch power of both the dummy MCF cores and the signal channel. The WDM pilot-tone was then connected to the remaining MCF core via the SDM MUX with 3 different cores selected during the measurements. The pilot-tone path also contained an EDFA and VOA with some additional fiber and an optical delay line used to align the optical path lengths. Previously [12

12. B. J. Puttnam, J. Sakaguchi, W. Klaus, Y. Awaji, J.-M. Delgado Mendinueta, N. Wada, A. Kanno, and T. Kawanishi, “Investigating self-homodyne coherent detection in a 19-core spatial-division-multiplexed transmission link,” Proc. ECOC '12, Paper Tu.3.C.3 (2012).

], measurements were performed over a range of temperatures which led to variations in the coupling efficiency. For the BER measurements reported here, thermal isolation was used to minimize thermal deviations and care was taken to ensure minimal variations of coupling efficiency, particularly on the center core which is most sensitive to crosstalk [10

10. W. Klaus, J. Sakaguchi, B. J. Puttnam, Y. Awaji, N. Wada, T. Kobayashi, and M. Watanabe, “Free-space coupling optics for multi-core fibers,” in Proceedings of IEEE Phot. Soc. Summer Topicals, WC3.3 (2012).

, 11

11. J. Sakaguchi, B. J. Puttnam, W. Klaus, Y. Awaji, N. Wada, A. Kanno, T. Kawanishi, K. Imamura, K. Inaba, K. Mukasa, R. Sugizaki, T. Kobayashi, and M. Watanabe, “19-core fiber transmission of 19×100×172-Gb/s SDM-WDM-PDM-QPSK signals at 305Tb/s,” Proc. OFC Paper PDP5C.1 (2012).

].

The OMA was used for constellation analysis and BER measurements and sampled at 40 GS/s with a 13 GHz analogue bandwidth. Chromatic dispersion compensation and polarization tracking were also performed in the OMA for all measurements and the impact of the phase tracking algorithm (PTA) was quantified by BER measurements for ID and SHCD. ID measurements were performed with the OMA’s internal laser with a linewidth of approximately 100 kHz and compared to SHCD with the WDM pilot-tone transmitted across 3 different MCF cores. Since path length is a critical issue for SHCD systems using higher order modulation formats, the relative variation of path length was monitored over temperature variations of 4°C before BER measurements were performed. The largest variation of optical length between pilot-tone and signal path observed was 0.8 cm or 40 ps over the whole transmission system. This was without any active compensation and included optical path length drift from other components. For example, after splitting from the pilot-tone, the signal path included 4 EDFAs, modulator, PCs, VOAs, OBPFs and connecting fibers, in addition to the MCF and coupling system.

3. Experimental results

3.1 Homodyne vs. intradyne detection

Initially, the phase noise cancellation was verified with both a single wavelength and WDM signals transmitted on an outer core of the MCF and the pilot-tone on the center core without signal light in the dummy MCF cores. Figure 2
Fig. 2 BER vs. OSNR for measured signal channel in single wavelength and WDM cases with/without receiver phase tracking (PT) for both SCHC and ID.
shows BER comparison of ID and SHCD for measurements with and without the PTA for both the WDM and single channel case.

Figure 2 shows that the best results are achieved with the receiver PTA employed and using ID. However, there is a penalty of almost 2 dB at BER = 10−3 when ID is used without the PTA. With SHCD employed, phase noise cancellation means that it is possible to achieve almost the same performance without the requirement of a potentially DSP intensive PTA [2

2. P. Johannisson, M. Sjödin, M. Karlsson, E. Tipsuwannakul, and P. Andrekson, “Cancellation of nonlinear phase distortion in self-homodyne coherent systems,” IEEE Photon. Technol. Lett. 22(11), 802–804 (2010). [CrossRef]

4

4. M. Sjödin, P. Johannisson, M. Karlsson, Z. Tong, and P. A. Andrekson, “OSNR requirements for self-homodyne coherent systems,” IEEE Photon. Technol. Lett. 22(2), 91–93 (2010). [CrossRef]

]. It should be noted that since only the signal was noise loaded, meaning the ASE on the LO was negligible compared to the signal, we did not observe the expected OSNR penalty for SHCD [4

4. M. Sjödin, P. Johannisson, M. Karlsson, Z. Tong, and P. A. Andrekson, “OSNR requirements for self-homodyne coherent systems,” IEEE Photon. Technol. Lett. 22(2), 91–93 (2010). [CrossRef]

]. Also, we note that the BER degradation for ID without the PTA is not as severe as expected for the laser linewidth and baud rate used. This is believed to be due to the proprietary DSP of the OMA which, even without the PTA enabled, estimates the phase at the beginning of each acquired trace in order to rotate the constellation for alignment before hard-detection. This, combined with the small size of the acquired traces (4,000 bits), reduces the impact of phase noise.

3.2 Measuring carrier phase estimation

Next, the impact of laser phase noise cancellation was investigated by employing a standard 64 samples-per-block Viterbi and Viterbi algorithm in order to track the carrier phase. Measurements were taken for center-core pilot-tone transmission with both the path length aligned and with path mis-aligned by removal of the entire MCF from the pilot-tone path to ensure decorrelation. Figure 3
Fig. 3 Carrier phase over 2 million bits for path length aligned and mis-aligned SHCD for both ECL and DFB laser transmission.
shows the estimated carrier phase evolution across a 200-µs span containing 2x106 bits using both the ECTL used previously and a DFB laser with linewidth measured to be 3 MHz at 193.6 THz, as light sources.

From Fig. 3, it is evident that even in the presence of the various noise sources including inter-core crosstalk, only a residual carrier phase correction is required for both laser types. This result verifies that the laser phase noise is cancelled when employing SHCD with goodpath alignment at the receiver. Without the path length alignment the receiver behaves as in the ID case and phase corrections of over a ± 600 rad range can be observed for both lasers. However, it is worth noting that the phase variations of the narrower linewidth ECTL appear smoother than the DFB case and so would reduce the likelihood of phase slips when using the ECTL with ID. Hence, these results show that regardless of the laser linewidth, in addition to frequency offset estimation, which no longer needs to be tracked since signal and LO originate from the same laser, SHCD can also greatly reduce the estimation time-scale required for carrier phase recovery, thus reducing the amount of necessary receiver DSP logic and consumed power compared to ID.

3.3. Measurement of SDM and WDM penalties

Figure 4
Fig. 4 (a) WDM and (b) SDM penalty for outer-core pilot-tone transmission.
shows the measurements of WDM and SDM penalties taken for SHDC with the WDM pilot-tone transmitted in an outer core of the 19-core MCF, but not neighboring the core carrying the measurement signal. Figure 4(a) shows the measured BER as a function of the OSNR for the system with 1, 4, 8 and 16 channels active and Fig. 4(b) shows the BER vs. OSNR plots as a function of the dummy signal fiber launch power relative to the pilot-tone launch power with signal and pilot-tone powers set to 0 dBm for all measurements.

3.4 Impact of inter-core crosstalk

Next, the impact of inter-core crosstalk on the performance of the system was investigated. This was done by comparing measurements with and without light in the dummy MCF cores and changing the core used for pilot-tone transmission, since crosstalk was previously observed to vary between cores, with center and inner cores experiencing the most severe crosstalk which may be up to 23 dB below the signal power [11

11. J. Sakaguchi, B. J. Puttnam, W. Klaus, Y. Awaji, N. Wada, A. Kanno, T. Kawanishi, K. Imamura, K. Inaba, K. Mukasa, R. Sugizaki, T. Kobayashi, and M. Watanabe, “19-core fiber transmission of 19×100×172-Gb/s SDM-WDM-PDM-QPSK signals at 305Tb/s,” Proc. OFC Paper PDP5C.1 (2012).

]. Hence, for the same outer core signal channel, 3 pilot-tone positions were investigated. These were a neighboring outer core, non-neighboring outer core and center core, shown as A, B and C respectively in the inset of Fig. 5
Fig. 5 Measurement of SDM penalties when transmitting pilot-tone on different fiber cores compared to case with the signal in a single core only (black squares).
, which shows BER curves for all 3 cases with the PTA disabled in each.

Overall, these results are intended to demonstrate the feasibility of exploiting the phase noise cancellation of SHCD with MCFs and more generally with SDM systems. Although a 19-core fiber was used in these measurements, SHCD should be possible with any MCF. Although higher core numbers enable greater spectral efficiency by sharing the pilot-tones between more signal channels, the core number and indeed the lengths of fiber over which SHCD is possible will be determined by the OSNR requirements of the receiver. Since both the OSNR-limiting inter-core crosstalk and the OSNR penalty of splitting the pilot-tones increase with core number, a clear trade-off exists to be investigated in future work.

4. Summary

We report a first investigation of the performance of transmission system combining self-homodyne coherent detection with an SDM transmission. Using a 19-core fiber and free-space coupling system, we transmitted a 16 wavelength local oscillator through 1 fiber core and 16 WDM information carrying signal channels in the remaining 18 cores. We showed that self-homodyne detection is compatible with SDM transmission, offering advantages of reduced receiver complexity and potentially enabling the use of lower cost transmitters with broader linewidth and reduced DSP requirements at the receiver. However, to exploit the advantages of self-homodyne detection in SDM transmission systems, it is necessary to consider and, where possible, minimize, the fiber’s inter-core crosstalk to achieve the best performance. Similarly, increasing the relative power of the pilot-tone may, also be considered an option to optimize performance since it is critical to successful reception of all signal channels.

Acknowledgments

The authors would like to thank M. Kurihara and T. Hashimoto for their technical assistance.

References and links

1.

T. Miyazaki, “Linewidth-Tolerant QPSK Homodyne Transmission Using a Polarization-Multiplexed Pilot Carrier,” IEEE Photon. Technol. Lett. 18(2), 388–390 (2006). [CrossRef]

2.

P. Johannisson, M. Sjödin, M. Karlsson, E. Tipsuwannakul, and P. Andrekson, “Cancellation of nonlinear phase distortion in self-homodyne coherent systems,” IEEE Photon. Technol. Lett. 22(11), 802–804 (2010). [CrossRef]

3.

M. Sjödin, E. Agrell, P. Johannisson, G.-W. Lu, P. A. Andrekson, and M. Karlsson, “Filter optimization for self-homodyne coherent WDM systems using interleaved polarization division,” J. Lightwave Technol. 29(9), 1219–1226 (2011). [CrossRef]

4.

M. Sjödin, P. Johannisson, M. Karlsson, Z. Tong, and P. A. Andrekson, “OSNR requirements for self-homodyne coherent systems,” IEEE Photon. Technol. Lett. 22(2), 91–93 (2010). [CrossRef]

5.

M. Sjödin, E. Agrell, P. Johannisson, G.-W. Lu, P. A. Andrekson, and M. Karlsson, “Interleaved polarization division multiplexing in self-homodyne coherent WDM systems,” Proc. ECOC '10, Mo.1.3.C (2010).

6.

G.-W. Lu, M. Nakamura, Y. Kamio, and T. Miyazaki, “40-Gb/s QPSK and 20-Gb/s PSK with inserted pilot symbols using self-homodyne detection,” Opt. Express 15(12), 7660–7666 (2007). [CrossRef] [PubMed]

7.

M. Nakamura, Y. Kamio, G.-W. Lu, and T. Miyazaki, “Ultimate linewidth-tolerant 20-Gbps QPSK-homodyne transmission using a spectrum-sliced ASE light source,” Proc. OFC’07, OThD4 (2007).

8.

Y. Kamio, M. Nakamura, and T. Miyazaki, “80-Gb/s 256-QAM signals using phase noise and DGD-tolerant pilot-carrier-aided homodyne detection,” Proc. ECOC’07, P089 (2007).

9.

B. Zhu, T. F. Taunay, M. Fishteyn, X. Liu, S. Chandrasekhar, M. F. Yan, J. M. Fini, E. M. Monberg, and F. V. Dimarcello, “112-Tb/s space-division multiplexed DWDM transmission with 14-b/s/Hz aggregate spectral efficiency over a 76.8-km seven-core fiber,” Opt. Express 19(17), 16665–16671 (2011). [CrossRef] [PubMed]

10.

W. Klaus, J. Sakaguchi, B. J. Puttnam, Y. Awaji, N. Wada, T. Kobayashi, and M. Watanabe, “Free-space coupling optics for multi-core fibers,” in Proceedings of IEEE Phot. Soc. Summer Topicals, WC3.3 (2012).

11.

J. Sakaguchi, B. J. Puttnam, W. Klaus, Y. Awaji, N. Wada, A. Kanno, T. Kawanishi, K. Imamura, K. Inaba, K. Mukasa, R. Sugizaki, T. Kobayashi, and M. Watanabe, “19-core fiber transmission of 19×100×172-Gb/s SDM-WDM-PDM-QPSK signals at 305Tb/s,” Proc. OFC Paper PDP5C.1 (2012).

12.

B. J. Puttnam, J. Sakaguchi, W. Klaus, Y. Awaji, J.-M. Delgado Mendinueta, N. Wada, A. Kanno, and T. Kawanishi, “Investigating self-homodyne coherent detection in a 19-core spatial-division-multiplexed transmission link,” Proc. ECOC '12, Paper Tu.3.C.3 (2012).

OCIS Codes
(060.2330) Fiber optics and optical communications : Fiber optics communications
(060.2920) Fiber optics and optical communications : Homodyning

ToC Category:
Transmission Systems and Network Elements

History
Original Manuscript: October 1, 2012
Revised Manuscript: November 5, 2012
Manuscript Accepted: November 5, 2012
Published: January 15, 2013

Virtual Issues
European Conference on Optical Communication 2012 (2012) Optics Express

Citation
Benjamin J. Puttnam, Jun Sakaguchi, José Manuel Delgado Mendinueta, Werner Klaus, Yoshinari Awaji, Naoya Wada, Atsushi Kanno, and Tetsuya Kawanishi, "Investigating self-homodyne coherent detection in a 19 channel space-division-multiplexed transmission link," Opt. Express 21, 1561-1566 (2013)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-21-2-1561


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. T. Miyazaki, “Linewidth-Tolerant QPSK Homodyne Transmission Using a Polarization-Multiplexed Pilot Carrier,” IEEE Photon. Technol. Lett.18(2), 388–390 (2006). [CrossRef]
  2. P. Johannisson, M. Sjödin, M. Karlsson, E. Tipsuwannakul, and P. Andrekson, “Cancellation of nonlinear phase distortion in self-homodyne coherent systems,” IEEE Photon. Technol. Lett.22(11), 802–804 (2010). [CrossRef]
  3. M. Sjödin, E. Agrell, P. Johannisson, G.-W. Lu, P. A. Andrekson, and M. Karlsson, “Filter optimization for self-homodyne coherent WDM systems using interleaved polarization division,” J. Lightwave Technol.29(9), 1219–1226 (2011). [CrossRef]
  4. M. Sjödin, P. Johannisson, M. Karlsson, Z. Tong, and P. A. Andrekson, “OSNR requirements for self-homodyne coherent systems,” IEEE Photon. Technol. Lett.22(2), 91–93 (2010). [CrossRef]
  5. M. Sjödin, E. Agrell, P. Johannisson, G.-W. Lu, P. A. Andrekson, and M. Karlsson, “Interleaved polarization division multiplexing in self-homodyne coherent WDM systems,” Proc. ECOC '10, Mo.1.3.C (2010).
  6. G.-W. Lu, M. Nakamura, Y. Kamio, and T. Miyazaki, “40-Gb/s QPSK and 20-Gb/s PSK with inserted pilot symbols using self-homodyne detection,” Opt. Express15(12), 7660–7666 (2007). [CrossRef] [PubMed]
  7. M. Nakamura, Y. Kamio, G.-W. Lu, and T. Miyazaki, “Ultimate linewidth-tolerant 20-Gbps QPSK-homodyne transmission using a spectrum-sliced ASE light source,” Proc. OFC’07, OThD4 (2007).
  8. Y. Kamio, M. Nakamura, and T. Miyazaki, “80-Gb/s 256-QAM signals using phase noise and DGD-tolerant pilot-carrier-aided homodyne detection,” Proc. ECOC’07, P089 (2007).
  9. B. Zhu, T. F. Taunay, M. Fishteyn, X. Liu, S. Chandrasekhar, M. F. Yan, J. M. Fini, E. M. Monberg, and F. V. Dimarcello, “112-Tb/s space-division multiplexed DWDM transmission with 14-b/s/Hz aggregate spectral efficiency over a 76.8-km seven-core fiber,” Opt. Express19(17), 16665–16671 (2011). [CrossRef] [PubMed]
  10. W. Klaus, J. Sakaguchi, B. J. Puttnam, Y. Awaji, N. Wada, T. Kobayashi, and M. Watanabe, “Free-space coupling optics for multi-core fibers,” in Proceedings of IEEE Phot. Soc. Summer Topicals, WC3.3 (2012).
  11. J. Sakaguchi, B. J. Puttnam, W. Klaus, Y. Awaji, N. Wada, A. Kanno, T. Kawanishi, K. Imamura, K. Inaba, K. Mukasa, R. Sugizaki, T. Kobayashi, and M. Watanabe, “19-core fiber transmission of 19×100×172-Gb/s SDM-WDM-PDM-QPSK signals at 305Tb/s,” Proc. OFC Paper PDP5C.1 (2012).
  12. B. J. Puttnam, J. Sakaguchi, W. Klaus, Y. Awaji, J.-M. Delgado Mendinueta, N. Wada, A. Kanno, and T. Kawanishi, “Investigating self-homodyne coherent detection in a 19-core spatial-division-multiplexed transmission link,” Proc. ECOC '12, Paper Tu.3.C.3 (2012).

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.

Figures

Fig. 1 Fig. 2 Fig. 3
 
Fig. 4 Fig. 5
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited