Free-Space Optical Communications

Contents

When an optical signal is transmitted through the atmosphere, atmospheric turbulence causes fluctuations in the amplitude and phase of the received wavefront, which can impair free-space optical links in much the same way that multipath fading affects radio-frequency wireless links. We have studied optical and electronic signal processing methods to overcome atmospheric turbulence, in links employing either coherent detection or direct detection. We have demonstrated free-space coherent transmission at mid-infrared wavelengths, where atmospheric effects are reduced, using nonlinear wavelength converters at the transmitter and receiver. We have studied acquisition and tracking algorithms for free-space links between moving platforms, such as aircraft.

Spatial Mode-Based Multiplexing and Turbulence Compensation Techniques

J. M. Kahn and A. Belmonte, "Modal Multiplexing and Atmospheric Turbulence Mitigation in Free-Space Optical Communications", tutorial presentation at Euro. Conf. on Optical Commun., Basel, Switzerland, September 18-22, 2022. PDF

A. Belmonte and J. M. Kahn, "Optimal Modes for Spatially Multiplexed Free-Space Communication in Atmospheric Turbulence", Optics Express, vol. 29, no. 26, pp. 43556-43566, December 20, 2021. PDF

N. Zhao, X. Li, G. Li and J. M. Kahn "Capacity Limits of Spatially Multiplexed Free-Space Communication", Nature Photon., vol. 9, pp. 822-826, December 2015. PDF

Free-Space Optical Transfer of Frequency, Time and Position

M. T. Taylor, A. Belmonte, L. Hollberg and J. M. Kahn, "Effect of Atmospheric Turbulence on Timing Instability for Partially Reciprocal Two-Way Optical Time Transfer Links", Phys. Rev. A, 101, 033843 (2020). PDF

A. Belmonte, M. T. Taylor, L. Hollberg and J. M. Kahn, "Effect of Atmospheric Anisoplanatism on Earth-to-Satellite Time Transfer over Laser Communication Links”, Optics Express, vol. 25, no. 14, pp. 15676-15686, July 10, 2017. PDF

P. Berceau, M. T. Taylor, J. M. Kahn and L. Hollberg, "Space-Time Reference with an Optical Link", Class. Quantum Grav., vol. 33, p. 135007, May 31, 2016. PDF

Adaptive Optics and Field Conjugation Arrays for Coherent Links

A. Belmonte and J. M. Kahn, "Sequential Optimization of Adaptive Arrays in Coherent Laser Communications", J. of Lightwave Technol., vol. 31, no. 9, pp. 1383-1387, May 1, 2013. PDF

A. Belmonte and J. M. Kahn, "Field Conjugation Adaptive Arrays in Free-Space Coherent Laser Communications", J. Optical Commun. Netw., vol. 3, no. 11, pp. 830-838, November 2011. PDF

A. Belmonte and J. M. Kahn, "Efficiency of Complex Modulation Methods in Coherent Free-Space Optical Links", Optics Express, vol. 18, no. 4, pp. 3928-3937, February 15, 2010. PDF

A. Belmonte and J. M. Kahn, "Analysis of a Field-Conjugation Adaptive Array for Coherent Free-Space Optical Links", Proc. of OSA Topical Meeting on Applications of Lasers for Sensing and Free Space Communications, San Diego, CA, January 31-February 3, 2010 (Invited Paper). PDF

A. Belmonte and J. M. Kahn, "Capacity of Coherent Free-Space Optical Links using Diversity Combining Techniques", Optics Express, vol. 17, no. 15, pp. 12601-12611, July 10, 2009. PDF

A. Belmonte and J. M. Kahn, "Capacity of Coherent Free-Space Optical Links using Atmospheric Compensation Techniques", Optics Express, vol. 17, no. 4, pp. 2763-1773, February 16, 2009. PDF

A. Belmonte and J. M. Kahn, "Performance of Synchronous Receivers using Atmospheric Compensation Techniques", Optics Express, vol. 16, no. 18, pp. 14151-14162, August 26, 2008. PDF

Wavelength Conversion for Coherent Links

E. Ip, D. Buchter, H. Herrmann, C. Langrock, J. M. Kahn, W. Sohler and M. M. Fejer, "QPSK Transmission over Free-Space Link at 3.8 Microns using Coherent Detection with Wavelength Conversion", Proc. of Euro. Conf. on Optical Commun., Brussels, Belgium, September 21-25, 2008. PDF

Array Receivers and Signal Processing Techniques for Direct-Detection Links

R. Nasiri Mahalati and J. M. Kahn, "Effect of Fog on Free-Space Optical Links Employing Imaging Receivers", Optics Express. vol. 20, no. 2, pp. 1649-1661, January 11, 2012. PDF

W. Mao and J. M. Kahn, "Free-space Heterochronous Imaging Reception of Multiple Optical Signals", IEEE Trans. on Commun., vol. 52, no. 2, pp. 269-279, February 2004. PDF

X. Zhu, J. M. Kahn and J. Wang, "Mitigation of Turbulence-Induced Scintillation Noise in Free-Space Optical Links using Temporal-Domain Detection Techniques", IEEE Photon. Technol. Lett., vol. 15, no. 4, pp. 623-625, April 2003. PDF

X. Zhu and J. M. Kahn, "Performance Bounds for Coded Free-Space Optical Communications through Atmospheric Turbulence Channels", IEEE Trans. on Commun., vol. 51, no. 8, pp. 1233-1239, August 2003. PDF

X. Zhu and J. M. Kahn, "Markov Chain Model in Maximum-Likelihood Sequence Detection for Free-Space Optical Communication through Atmospheric Turbulence Channels", IEEE Trans. on Commun., vol. 51, no. 3, pp. 509-516, March 2003. PDF

X. Zhu and J. M. Kahn, "Free-Space Optical Communication through Atmospheric Turbulence Channels", IEEE Trans. on Commun., vol. 50, no. 8, pp. 1293-1300, August 2002. PDF

X. Zhu and J. M. Kahn, "Pilot Symbol-Assisted Modulation for Correlated Turbulent Free-Space Optical Channels", Proc. of SPIE Intl. Symp. on Optical Science and Technol., San Diego, CA, July 29-August 3, 2001. The version published in the conference proceedings contains some minor typographical errors that are corrected in this version. PDF

Acquisition and Tracking Algorithms

J. Wang, J. M. Kahn and K. Y. Lau "Minimization of Acquisition Time in Short-Range Free-Space Optical Communication", Applied Optics, vol. 41, no. 12, pp. 7592-7602, December 2002. PDF

Indoor Free-Space Optical Communications

Free-space optics is a promising medium for short-range, indoor wireless communications, offering high bit rates and dense spatial reuse. Our research has involved both theoretical and experimental studies. Theoretical work has addressed orthogonal frequency-division multiplexing, equalization for single-carrier modulation, trellis-coded pulse-position modulation, rate-adaptive coding techniques, and multiple-access techniques. On the experimental front, we have characterized multipath channels, tested several novel optical receiving "antenna" designs, and demonstrated prototype non-line-of-sight communication links operating at bit rates up to 100 Mbit/s. We designed a wireless video distribution system for airliner cabins that has an aggregate throughput of approximately 1 Gbit/s.

Review Articles

J.M. Kahn and J. R. Barry, "Wireless Infrared Communications", Proc. of the IEEE, vol. 85, pp. 265-298, February 1997. (Invited Paper). PDF

Modulation, Coding and Equalization Techniques

D. J. F. Barros, S. K. Wilson and J. M. Kahn, "Comparison of Orthogonal Frequency-Division Multiplexing and Pulse-Amplitude Modulation in Indoor Optical Wireless Links", IEEE Trans. on Commun., vol. 60, no. 1, pp. 153-163, January 2012. 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

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

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

D. Shiu and J. M. Kahn, "Differential Pulse-Position Modulation for Power-Efficient Optical Communication", IEEE Trans. on Commun., vol. 47, no. 8, pp. 1201-1210, August 1999. PDF

M.D. Audeh, J. M. Kahn and J. R. Barry, "Decision-Feedback Equalization of Pulse-Position Modulation on Measured Non-Directed Indoor Infrared Channels", IEEE Trans. on Commun., vol. 47, pp. 500-503, April 1999. PDF

L. Diana and J. M. Kahn, "Rate-Adaptive Modulation Techniques for Infrared Wireless Communications", Proc. of IEEE Intl. Conf. on Commun., Vancouver, B.C., Canada, June 6-10, 1999. The version published in the conference proceedings contains some minor typographical errors that are corrected in this version. PDF

D.C. Lee and J. M. Kahn, "Coding and Equalization for PPM on Wireless Infrared Channels", IEEE Trans. on Commun., vol. 47, no. 2, pp. 255-260, February 1999. PDF

D.C. Lee, J. M. Kahn and M. D. Audeh, "Trellis-Coded Pulse-Position Modulation for Indoor Wireless Infrared Communications", IEEE Trans. on Commun., vol. 45, pp. 1080-1087, September 1997. PDF

M.D. Audeh, J. M. Kahn and J. R. Barry, "Performance of Pulse-Position Modulation on Measured Non-Directed Indoor Infrared Channels", IEEE Trans. on Commun., vol. 44, pp. 654-659, June 1996. PDF

J.B. Carruthers and J. M. Kahn, "Multiple-Subcarrier Modulation for Non-Directed Wireless Infrared Communication", IEEE J. Sel. Areas in Commun., vol. 14, pp. 538-546, April 1996. PDF

Diversity Detection Techniques

P. Djahani and J. M. Kahn, "Analysis of Infrared Wireless Links Employing Multi-Beam Transmitters and Imaging Diversity Receivers", IEEE Trans. on Commun., vol. 48, no. 12, pp. 2077-2088, December 2000. PDF

J.M. Kahn, P. Djahani, A. G. Weisbin, K. T. Beh, A. P. Tang and R. You, "Imaging Diversity Receivers for High-Speed Infrared Wireless Communication", IEEE Commun. Mag., vol. 36, no. 12, pp. 88-94, December 1998. PDF

J.B. Carruthers and J. M. Kahn, "Angle Diversity for Nondirected Wireless Infrared Communication", IEEE Trans. on Commun. vol. 48, no. 6, pp. 960-969, June 2000. PDF

Multiple-Access Techniques

F. Chow and J. M. Kahn, "Effect of Non-Reciprocity on Infrared Wireless Local-Area Networks", Proc. of IEEE Global Commun. Conf., Rio de Janeiro, Brazil, December 5-9, 1999. PDF For a more detailed description of this work, see: F. Chow, "Effect of Non-Reciprocity on Infrared Wireless Local-Area Networks", M.S. Report, University of California, Berkeley, December 1998. PDF

G. W. Marsh and J. M. Kahn, "Channel Reuse Strategies for Indoor Infrared Wireless Communications", IEEE Trans. on Commun., vol. 45, no. 10, pp. 1280-1290, October 1997. PDF

Channel Characterization and Modeling

J. B. Carruthers and J. M. Kahn, "Modeling of Nondirected Wireless Infrared Channels", IEEE Trans. on Commun., vol. 45, no. 10, pp. 1260-1268, October 1997. PDF

J. M. Kahn, W. J. Krause and J. B. Carruthers, "Experimental Characterization of Non-Directed Indoor Infrared Channels", IEEE Trans. on Commun., vol. 43, pp. 1 613-1623, April 1995. PDF

J. R. Barry, J. M. Kahn, W. J. Krause, E. A. Lee, and D. G. Messerschmitt, "Simulation of Multipath Impulse Response for Wireless Optical Channels", IEEE J. Sel. Areas in Commun., vol. 11, no. 3, pp. 367-379, April 1993. PDF

Receiver Optics

J. R. Barry and J. M. Kahn, "Link Design for Non-Directed Wireless Infrared Communications", Applied Optics, vol. 34, no. 19, pp. 3764-3776, July 1995. PDF

K.-P. Ho and J. M. Kahn, "Compound Parabolic Concentrators for Narrow-Band Wireless Infrared Receivers", Optical Engineering, vol. 34, no. 5, pp. 1385-1395, May 1995. PDF

Prototype Communication Links

J. B. Carruthers and J. M. Kahn, "Angle Diversity for Nondirected Wireless Infrared Communication", IEEE Trans. on Commun. vol. 48, no. 6, pp. 960-969, June 2000. PDF

D. C. Lee and J. M. Kahn, "Experimental 25-Mb/s Wireless Infrared Link Using 4-PPM with Scalar Decision-Feedback Equalization", Proc. of IEEE Intl. Conf. on Commun., Atlanta, GA, June 7-11, 1998. PDF

G. W. Marsh and J. M. Kahn, "Performance Evaluation of Experimental 50-Mb/s Diffuse Infrared Wireless Link using On-Off Keying with Decision-Feedback Equalization", IEEE Trans. on Commun., vol. 44, no. 11, pp. 1496-1504, November 1996. PDF

G. W. Marsh and J. M. Kahn, "50-Mb/s Diffuse Infrared Free-Space Link using On-Off Keying with Decision-Feedback Equalization", IEEE Photon. Technol. Lett., vol. 6, no. 10, pp. 1268-1270, October 1994. PDF

Free-Space Optical Communications for MEMS-Based Sensor Nodes ("Smart Dust")

We performed pioneering studies of distributed networks of millimeter-scale sensor nodes implemented using microelectromechanical systems, which we called "Smart Dust". Smart Dust might be deployed in an environment (indoor or outdoor) to sense and record data of interest. We implemented free-space optical links for interrogation of Smart Dust. A novel uplink design used a sub-millimeter corner-cube retroreflector on each dust mote, which is illuminated from a central transceiver, permitting dust motes to transmit information without having to radiate any power. We developed optical MEMS devices for free-space communications, including corner-cube retroreflectors and two-axis beam scanners.

Communication and Networking Architectures for Smart Dust

W. Mao and J. M. Kahn, "Free-space Heterochronous Imaging Reception of Multiple Optical Signals", IEEE Trans. on Commun., vol. 52, no. 2, pp. 269-279, February 2004. PDF

B. A. Warneke, M. D. Scott, B. S. Liebowitz, L. Zhou, C. L. Bellew, J. A. Chediak, J. M. Kahn, B. E. Boser and K. S. J. Pister, "An Autonomous 16 mm³ Solar-Powered Node for Distributed Wireless Sensor Networks", Proc. of IEEE Sensors 2002 Conference, Orlando, FL, June 12-14, 2002. PDF

J. M. Kahn, R. H. Katz, and K. S. J. Pister, "Emerging Challenges: Mobile Networking for Smart Dust", J. of Commun. and Networks, vol. 2, no. 3, pp. 188-196, September 2000 (Invited Paper). PDF

J. M. Kahn, R. H. Katz and K. S. J. Pister, "Mobile Networking for Smart Dust", Proc. of ACM/IEEE Intl. Conf. on Mobile Computing and Networking (MobiCom 99), Seattle, WA, August 17-19, 1999. (Voted Best Paper in Session.) PDF

MEMS Devices for Free-Space Optical Communications

L. Zhou, J. M. Kahn and K. S. J. Pister, "Scanning Micromirrors Fabricated by an SOI/SOI Wafer Bonding Process", IEEE J. of Microelectromech. Syst., vol. 15, no. 1, pp. 24-32, February 2006. PDF

L. Zhou, J. M. Kahn and K. S. J. Pister, "Corner-Cube Retroreflectors Based on Structure-Assisted Assembly for Free-Space Optical Communication", IEEE J. of Microelectromechanical Syst., vol. 12, no. 3, pp. 233-242, June 2003. PDF

X. Zhu, V. S. Hsu and J. M. Kahn, "Optical Modeling of MEMS Corner Cube Retroreflectors with Misalignment and Non-flatness", IEEE J. on Sel. Topics in Quantum Electron., vol. 8, no. 1, pp. 26-32, January/February 2002. PDF

Return to Joseph M. Kahn's home page.

Last modified: September 1, 2022.