Multi-Mode Fiber Communications

Multimode fiber has been used traditionally for short-range links in data centers and local-area networks. In such direct-detection links, the primary impairment is modal dispersion caused by propagation in multiple modes having different group delays. Commercial systems are limited currently to 10 Gbit/s over a 300-m fiber length. We have done pioneering studies of mode coupling, leading to the identification of principal modes, which are free of modal dispersion to first order in frequency. Experimentally, we have used adaptive optics to launch signals into principal modes, allowing single-input, single-output (SISO) transmission orders of magnitude beyond traditional bandwidth-distance limits (for example, 10 Gbit/s over 11 km and 100 Gbit/s over 2.2 km). We are working to extend this approach to enable mode-division multiplexing, a form of multi-input, multi-output (MIMO) transmission, in order to increase transmission capacity in direct-detection systems.

Recently, the prospect of a "capacity crunch" in the core of the Internet has stimulated widespread interest in mode-division multiplexing for long-haul systems using coherent detection. Such MIMO transmission might increase transmission capacity from the current 100 Gbit/s per wavelength (10 Tbit/s per fiber) to about 1 Tbit/s per wavelength (100 Tbit/s per fiber). Recently, we have performed fundamental studies in this area. We have derived the statistical properties of modal group delays and of mode-dependent gains and losses, allowing us to study information-theoretic limits imposed by these effects. Currently, we are developing multimode optical amplifiers with low mode-dependent gain, and are developing techniques for compensation of mode-dependent gains and losses. We have also performed extensive related research on coherent systems in single-mode fiber.

Propagation and Mode Coupling in Multimode Fibers

J. M. Kahn and K.-P. Ho, "Mode-Division Multiplexing Systems: Propagation Effects, Performance and Complexity", Proc. of Optical Fiber Commun. Conf., Anaheim, CA, March 17-21, 2013 (Invited Tutorial). PDF

K.-P. Ho and J. M. Kahn, "Mode Coupling and its Impact on Spatially Multiplexed Systems", in Optical Fiber Telecommunications VI, I. P. Kaminow, T. Li and A. E. Willner, Eds., Elsevier, Amsterdam, 2013 (Invited Chapter). PDF

K.-P. Ho and J. M. Kahn, "Delay-Spread Distribution for Multimode Fiber with Strong Mode Coupling", IEEE Photon. Technol. Lett., vol. 24, no. 21, pp. 1906-1909, November 1, 2012. PDF

J. M. Kahn, K.-P. Ho and M. B. Shemirani, "Mode Coupling Effects in Multi-Mode Fibers", Proc. of Optical Fiber Commun. Conf., Los Angeles, CA, March 4-8, 2012 (Invited Paper). PDF

K.-P. Ho and J. M. Kahn, "Statistics of Group Delays in Multimode Fiber with Strong Mode Coupling", J. of Lightwave Technol., vol. 29, no. 21, pp. 3119-3128, November 1, 2011. PDF

M. B. Shemirani and J. M. Kahn, "Higher-Order Modal Dispersion in Graded-Index Multimode Fiber", J. of Lightwave Technol., vol. 27, no. 23, pp. 5461-5468, December 1, 2009. PDF

M. B. Shemirani, W. Mao, R. A Panicker and J. M. Kahn, "Principal Modes in Graded-Index Multimode Fiber in Presence of Spatial- and Polarization-Mode Coupling", J. of Lightwave Technol., vol. 27, no. 10, pp. 1248-1261, May 15, 2009. PDF See also the errata: PDF

S. Fan and J. M. Kahn, "Principal Modes in Multi-Mode Waveguides", Optics Letters, vol. 30, no. 2, pp. 135-137, January 15, 2005. PDF

Long-Haul Coherent Systems: Performance and MIMO Signal Processing Techniques

S. O. Arik, D. Askarov and J. M. Kahn, "Effect of Mode Coupling on Signal Processing Complexity in Mode-Division Multiplexing", J. of Lightwave Technol. vol. 31, no. 13, pp. 423-431, February 1, 2013. PDF

K.-P. Ho and J. M. Kahn, "Frequency Diversity in Mode-Division Multiplexing Systems", J. of Lightwave Technol., vol. 29, no. 24, pp. 3719-3726, December 15, 2011. PDF

K.-P. Ho and J. M. Kahn, "Mode-Dependent Loss and Gain: Statistics and Effect on Mode-Division Multiplexing", Optics Express, vol. 19, no. 17, pp. 16612-16635, August 15, 2011 (Invited Paper). PDF

Long-Haul Coherent Systems: Components and Subsystems

D. Askarov and J. M. Kahn, "Design of Transmission Fibers and Doped Fiber Amplifiers for Mode-Division Multiplexing", IEEE Photon. Technol. Lett., vol. 24, no. 21, pp. 1945-1948, November 1, 2012. PDF

Direct-Detection Systems: Adaptive Optics for SISO and MIMO Transmission

M. B. Shemirani, J. P. Wilde and J. M. Kahn, "Adaptive Compensation of Multimode Fiber Dispersion by Control of Launched Amplitude, Phase, and Polarization", J. of Lightwave Technol., vol. 28, no. 18, pp. 2627-2639, September 15, 2010. PDF

M. B. Shemirani and J. M. Kahn, "Compensation of Multimode Fiber Dispersion by Optimization of Launched Amplitude, Phase, and Polarization", J. of Lightwave Technol., vol. 28, no. 14, pp. 2084-2095, July 15, 2010. PDF

R. A. Panicker and J. M. Kahn, "Algorithms for Compensation of Multimode Fiber Dispersion using Adaptive Optics", J. of Lightwave Technol., vol. 27, no. 24, pp. 5790-5799, December 15, 2009. PDF

R. A. Panicker, J. M. Kahn and S. P. Boyd, "Compensation of Multimode Fiber Dispersion using Adaptive Optics via Convex Optimization", J. of Lightwave Technol., vol. 26, no. 10, pp. 1295-1305, May 2008. PDF

E. Alon, V. Stojanovic, J. M. Kahn, S. P. Boyd and M. A. Horowitz, "Equalization of Modal Dispersion in Multimode Fiber using Spatial Light Modulators", Proc. of IEEE Global Telecommun. Conf., Dallas, TX, Nov. 29-Dec. 3, 2004. PDF

Direct-Detection Systems: Adaptive Optics Transmission Experiments

M. B. Shemirani, J. P. Wilde and J. M. Kahn, "Adaptive Compensation of Multimode Fiber Dispersion by Control of Launched Amplitude, Phase, and Polarization", J. of Lightwave Technol., vol. 28, no. 18, pp. 2627-2639, September 15, 2010. PDF

R. A. Panicker, A. P. T. Lau, J. P. Wilde and J. M. Kahn, "Experimental Comparison of Adaptive Optics Algorithms in 10-Gb/s Multimode Fiber Systems", J. of Lightwave Technol., vol. 27, no. 24, pp. 5783-5789, December 15, 2009. PDF

R. A. Panicker, J. P. Wilde, J. M. Kahn, D. F. Welch and I. Lyubomirsky, "10 x 10 Gb/s DWDM Transmission Through 2.2 km Multimode Fiber Using Adaptive Optics", IEEE Photon. Technol. Lett. , vol. 19, no. 15, pp. 1154-1156, August 1, 2007. PDF Here is an animated PowerPoint presentation of this experiment. View it in slide show mode. Watch the movie on slide 11 (click twice on the graphic).

X. Shen, J. M. Kahn and M. A. Horowitz, "Compensation for Multimode Fiber Dispersion by Adaptive Optics", Optics Letters, vol. 30, no. 22, pp. 2985-2987, November 15, 2005. PDF Here is an animated PowerPoint presentation of this experiment. View it in slide show mode. Watch the movie on slide 6 (click twice on the graphic).

Direct-Detection Systems: Modulation and Equalization Techniques

D. J. F. Barros and J. M. Kahn, "Comparison of Orthogonal Frequency-Division Multiplexing and On-Off Keying in Direct-Detection Multimode Fiber Links", J. of Lightwave Technol., vol. 29, no. 15, pp. 2299-2309, August 1, 2011. PDF

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Last modified: March 26, 2013.