Single-Mode Fiber Communications

Our research addresses coding, modulation, detection and signal processing techniques to maximize spectral efficiency and robustness against transmission impairments in high-capacity transmission systems. This work helped enable current-generation 100 Gbit/s long-haul systems using polarization-multiplexed QPSK with coherent detection. Our research is now aimed at enabling next-generation systems to achieve bit rates of 400 Gbit/s to beyond 1 Tbit/s per channel.

Over more than two decades, we have performed seminal research on coherent optical detection. In the late 1980s, we demonstrated the first optical phase-locked loop using semiconductor lasers, and built BPSK homodyne transmission systems that achieved record receiver sensitivities (as low as 38 photons/bit). In 1992, we demonstrated coherent detection of QPSK, a technique offering high spectral efficiency and high receiver sensitivity.

More recently, we have been studying digital signal processing techniques for carrier recovery and compensation of transmission impairments. These include linear effects, such as chromatic dispersion and polarization-mode dispersion, as well as nonlinear effects arising from the Kerr nonlinearity in silica glass. We have studied important practical issues, for example, using polyphase digital filters to reduce receiver sampling rates well below 2 samples/symbol (which was widely believed to be the minimum required). At the same time, we have addressed fundamental issues, for example, using digital backpropagation to cancel fiber nonlinearity (which was widely believed to pose insuperable performance limitations). We have also performed extensive research on fundamental limits to spectral efficiency dictated by information theory.

We are now studying bandwidth-scalable transmission based on orthogonal frequency-division multiplexing (OFDM) and rate-adaptive transmission based on low-density parity-check (LDPC) codes. These will help enable 400 Gbit/s-per-channel and 1 Tbit/s-per-channel long-haul systems to become a practical reality. With the goal of exploiting spatial dimensions to further increase transmission capacity, we are also performing research on coherent mode-division multiplexing in multi-mode fiber, a form of multi-input, multi-output (MIMO) transmission.

Coherent Systems: Review Articles

E. Ip, A. P. T. Lau, D. J. F. Barros and J. M. Kahn, "Coherent Detection in Optical Fiber Systems", Optics Express, vol. 16, no. 2, pp. 753-791, January 21, 2008 (Invited Paper). PDF

E. Ip and J. M. Kahn, "Fiber Impairment Compensation using Coherent Detection and Digital Signal Processing", J. of Lightwave Technol., vol. 28, no. 4, pp. 502-519, February 15, 2010 (Invited Paper). PDF

Coherent Systems: Bandwidth-Scalable and Rate-Adaptive Transmission Techniques

M. Sharif and J. M. Kahn, "Variable-Bandwidth Superchannels Using Synchronized Colorless Transceivers", J. of Lightwave Technol., vol. 32, no. 10, pp. 1921-1929, May 15, 2014. PDF

L. Beygi, E. Agrell, J. M. Kahn, and M. Karlsson, "Coded Modulation for Fiber-Optic Networks", IEEE Signal Processing Magazine, vol. 31, pp. 93-103, March 2014. PDF

D. A. A. Mello, A. N. Barreto, T. C. Lima, T. F. Portela, L. Beygi and J. M. Kahn, "Optical Networking with Variable-Code-Rate Transceivers", J. of Lightwave Technol., vol. 32, pp. 257-266, January 15, 2014. PDF

L. Beygi, E. Agrell, J. M. Kahn, and M. Karlsson, "Rate-Adaptive Coded Modulation for Fiber-Optic Communications", J.of Lightwave Technol., vol. 32, pp. 333-343, January 15, 2014. PDF

D. J. F. Barros, J. M. Kahn, J. P. Wilde and T. Abou Zeid, "Bandwidth-Scalable Long-Haul Transmission using Synchronized Colorless Transceivers and Efficient Wavelength-Selective Switches", J. of Lightwave Technol., vol. 30, no. 16, pp. 2646-2660, August 15, 2012. PDF

G.-H. Gho and J. M. Kahn, "Rate-Adaptive Modulation and Low-Density Parity-Check Coding for Optical Fiber Transmission Systems", J. Optical Commun. Netw., vol. 4, no. 10, pp. 760-768, October 2012. PDF

G.-H. Gho and J. M. Kahn, "Rate-Adaptive Modulation and Coding for Optical Fiber Transmission Systems", J. of Lightwave Technol., vol. 30, no. 12, pp. 1818-1812, June 15, 2012. PDF

G.-H. Gho, L. Klak and J. M. Kahn, "Rate-Adaptive Coding for Optical Fiber Transmission Systems", J. of Lightwave Technol., vol. 29, no. 2, pp. 222-233, January 15, 2011. PDF

Coherent Systems: Linear and Nonlinear Impairments and Compensation Techniques

E. Ip and J. M. Kahn, "Time-Reversed Twin", Nature Photonics, vol. 7, pp. 507-508, July 2013 (Invited Paper). PDF Also see this related paper by X. Liu et al: PDF

E. Ip and J. M. Kahn, "Nonlinear Impairment Compensation using Backpropagation", in Optical Fibre, New Developments, C. Lethien, Ed., In-Tech, Vienna Austria, December 2009 (Invited Chapter). Online

E. Ip and J. M. Kahn, "Compensation of Dispersion and Nonlinear Effects using Digital Backpropagation", J. of Lightwave Technol., vol. 26, no. 20, pp. 3416-3425, October 15, 2008. PDF

D. J. F. Barros and J. M. Kahn, "Optical Modulator Optimization for Orthogonal Frequency-Division Multiplexing", J. of Lightwave Technol., vol. 27, no. 13, pp. 2370-2378, July 1, 2009. PDF

D. J. F. Barros and J. M. Kahn, "Optimized Dispersion Compensation Using Orthogonal Frequency-Division Multiplexing", J. of Lightwave Technol., vol. 26, no. 16, pp. 2889-2898, August 15, 2008. PDF

E. Ip and J. M. Kahn, "Digital Equalization of Chromatic Dispersion and Polarization Mode Dispersion", J. of Lightwave Technol., vol. 25, no. 8, pp. 2033-2043, August 2007. PDF

A. P. T. Lau, S. Rabbani and J. M. Kahn, "On the Statistics of Intra-Channel Four-Wave Mixing in Phase-Modulated Optical Communication Systems", J. of Lightwave Technol., vol. 26, no. 14, pp. 2128-2135, July 15, 2008. PDF

A. P. T. Lau and J. M. Kahn, "Signal Design and Detection in Presence of Nonlinear Phase Noise", J. of Lightwave Technol., vol. 25, no. 10, pp. 3008-3016, October 2007. PDF

A. P. T. Lau and J. M. Kahn, "Power Profile Optimization in Phase-Modulated Systems in Presence of Nonlinear Phase Noise", IEEE Photon. Technol. Lett., vol. 18, no. 23, pp. 2514-2516, December 1, 2006. PDF

A. P. T. Lau and J. M. Kahn, "Design of Inline Amplifier Gains and Spacings to Minimize Phase Noise in Optical Transmission Systems", J. of Lightwave Technol., vol. 24, no. 3, pp. 1334-1341, March 2006. PDF

K.-P. Ho and J. M. Kahn, "Electronic Compensation Technique to Mitigate Nonlinear Phase Noise", J. of Lightwave Technol., vol. 22, no. 3, pp. 779-783, March 2004. PDF

Coherent Systems: Carrier Phase Recovery Techniques

E. Ip and J. M. Kahn, "Feedforward Carrier Recovery for Coherent Optical Communications", J. of Lightwave Technol., vol. 25, no. 9, pp. 2675-2692, September 2007. PDF See also: E. Ip and J. M. Kahn, "Addendum to: Feedforward Carrier Recovery for Coherent Optical Communications", J. of Lightwave Technol., vo. 27, no. 13, pp. 2552-2553, July 1, 2009 PDF

E. Ip and J. M. Kahn, "Carrier Synchronization for 3- and 4-bit-per-Symbol Optical Transmission", J. of Lightwave Technol., vol. 23, no. 12, pp. 4110-4124, December 2005. PDF

J. R. Barry and J. M. Kahn, "Carrier Synchronization for Homodyne and Heterodyne Detection of Optical Quadriphase-Shift Keying", J. Lightwave Technol., vol. 10, pp. 1939-1951, 1992. PDF

Coherent Systems: Transmission Experiments and Associated Components

E. Ip, J. M. Kahn, D. Anthon and J. Hutchins, "Linewidth Measurements of MEMS-Based Tunable Lasers for Phase-Locking Applications", IEEE Photon. Technol. Lett., vol. 17, no. 10, pp. 2029-2031, October 2005. PDF

K.-P. Ho and J. M. Kahn, "Optical Frequency Comb Generator Using Phase Modulation in Amplified Circulating Loop", Photon. Technol. Lett., vol. 5, no. 6, pp. 721-725, June 1993. PDF

J. M. Kahn, A. M. Porter and U. Padan, "Heterodyne Detection of 310-Mb/s Quadriphase-Shift Keying Using Fourth-Power Optical Phase-Locked Loop", IEEE Photon. Technol. Lett., vol. 4, pp. 1397-1400, 1992. PDF

J. M. Kahn, A. H. Gnauck, J. J. Veselka, S. K. Korotky and B. L. Kasper, "4 Gbit/s PSK Homodyne Transmission System Using Phase-Locked Semiconductor Lasers," IEEE Photon. Technol. Lett., vol. 2, pp. 285-287, 1990. PDF

J. M. Kahn, "1 Gbit/s PSK Homodyne Transmission System Using Phase-Locked Semiconductor Lasers," IEEE Photon. Technol. Lett., vol. 1, pp. 340-342, 1989. PDF

J. M. Kahn, C. A. Burrus and G. Raybon, "High-Stability 1.5 Micron External-Cavity Lasers for Phase-Lock Applications," IEEE Photon. Technol. Lett., vol. 1, pp. 159-161, 1989. PDF

J. M. Kahn and B. L. Kasper, "Optical Phaselock Receiver with Multi-Gigahertz Signal Bandwidth", Electron. Lett. vol. 25, pp. 626-627, 1989. PDF

Direct-Detection Systems: Linear and Nonlinear Impairments and Compensation Techniques

D. J. F. Barros and J. M. Kahn, "Comparison of Orthogonal Frequency-Division Multiplexing and On-Off Keying in Amplified Direct-Detection Single-Mode Fiber Systems", J. of Lightwave Technol., vol. 28, no. 12, pp. 1811-1820, June 15, 2010. PDF

J. Wang and J. M. Kahn, "Accurate Bit-Error Ratio Computation in Nonlinear CRZ-OOK and CRZ-DPSK Systems", IEEE Photon. Technol. Lett., vol. 16, no. 9, pp. 2165-2167, September 2004. PDF

J. Wang and J. M. Kahn, "Conventional DPSK vs. Symmetrical DPSK: Comparison of Dispersion Tolerances", IEEE Photon. Technol. Lett., vol. 16, no. 6, pp. 1585-1587, June 2004. PDF

J. Wang and J. M. Kahn, "Performance of Electrical Equalizers in Optically Amplified OOK and DPSK Systems", IEEE Photon. Technol. Lett., vol. 16, no. 5, pp. 1397-1399, May 2004. PDF

J. Wang and J. M. Kahn, "Impact of Chromatic and Polarization-Mode Dispersions on DPSK Systems using Interferometric Demodulation and Direct Detection", J. of Lightwave Technol., vol. 22, no. 2, pp. 362-371, February 2004. PDF

Information-Theoretic Limits

J. M. Kahn and K.-P. Ho, "Spectral Efficiency Limits and Modulation/Detection Techniques for DWDM Systems", IEEE. J. on Sel. Topics in Quantum Electron., vol. 10, no. 2, pp. 259-272, March/April 2004 (Invited Paper). PDF

K.-P. Ho and J. M. Kahn, "Channel Capacity of WDM Systems Using Constant-Intensity Modulation Formats", Proc. of Optical Fiber Commun. Conf., Anaheim, CA, March 17-22, 2002. PDF

J. M. Kahn and K.-P. Ho, "A Bottleneck for Optical Fibres", Nature, vol. 411, pp. 1007-1010, June 28, 2001 (Invited Paper). PDF Also see this related paper by Mitra and Stark: PDF

Coding and Modulation Techniques

E. Ip and J. M. Kahn, "Power Spectra of Return-to-Zero Optical Signals", J. of Lightwave Technol., vol. 24, no. 3, pp. 1610-1618, March 2006. PDF

K.-P. Ho and J. M. Kahn, "Spectrum of Externally Modulated Optical Signals", J. of Lightwave Technol., vol. 22, no. 2, pp. 658-663, February 2004. PDF

W. Mao and J. M. Kahn, "Lattice Codes for Amplified Direct-Detection Optical Systems", IEEE Trans. on Commun., vol. 56, no. 7, pp. 1137-1145, July 2008. PDF

D. Shiu and J. M. Kahn, "Shaping and Non-Equiprobable Signaling for Intensity Modulated Signals", IEEE Trans. on Information Theory, vol. 45, pp. 2661-2668, November 1999. PDF

Subcarrier-Multiplexed Systems

R. You and J. M. Kahn, "Upper-Bounding the Capacity of Optical IM/DD Channels with Multiple-Subcarrier Modulation and Fixed Bias using Trigonometric Moment Space Method", IEEE Trans. on Info. Theory, vol. 48, pp. 514-523, February 2002. PDF

R. You and J. M. Kahn, "Average Power Reduction Techniques for Multiple-Subcarrier Intensity-Modulated Optical Signals", IEEE Trans. on Commun., vol. 49, pp. 2164-2171, December 2001. PDF

K.-P. Ho and J. M. Kahn, "Optimal Predistortion of Gaussian Inputs for Clipping Channels", IEEE Trans. on Commun., vol. 44, no. 11, pp. 1505-1513, November 1996. PDF

K.-P. Ho and J. M. Kahn, "On Models of Clipping Distortion for Lightwave CATV Systems", IEEE Photon. Technol. Lett., vol. 8, no. 1, pp. 125-126, January 1996. PDF

K.-P Ho and J. M. Kahn, "Equalization Technique to Reduce Laser Clipping-Induced Distortion in Subcarrier-Multiplexed Lightwave Systems", IEEE Photon. Technol. Lett., vol. 5, no. 9, pp. 1100-1103, September 1993. PDF

Optical Networks

X. Zhu and J. M. Kahn, "Queueing Models of Optical Delay Lines in Synchronous and Asynchronous Optical Packet-Switching Networks", Optical Engineering, vol.42, no.6, pp.1741-1748, June 2003. PDF

K.-P. Ho and J. M. Kahn, "Methods for Crosstalk Measurement and Reduction in Dense WDM Systems", J. Lightwave Technol., vol. 14., pp. 1127-1135, June 1996. PDF


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Last modified: June 3, 2014.