Abstract

This article describes observations made during a recent series of single-mode lasercom experiments in which high-rate data transmission was demonstrated between a small aircraft and a ground station separated by distances up to 80 km. A significant result of the subsequent data analysis was the discovery of near-unity correlations between the signal fluctuations observed by power monitors at the two ends of the link. This evidence of reciprocity is presented, along with the description of a preliminary concept for utilizing this channel state information to improve link performance.

© 2012 OSA

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References

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  1. H. A. Lorentz, “The theorem of poynting concerning the energy in the electromagnetic field and two general propositions concerning the propagation of light,” Versl. Kon. Akad. Wentensch. Amsterdam4, 176–187 (1896).
  2. J. H. Shapiro, “Reciprocity of the turbulent atmosphere,” J. Opt. Soc. Am.61(4), 492–495 (1971).
    [CrossRef]
  3. R. F. Lutomirski and H. T. Yura, “Propagation of a finite optical beam in an inhomogeneous medium,” Appl. Opt.10(7), 1652–1658 (1971).
    [CrossRef] [PubMed]
  4. R. R. Parenti, S. Michael, J. M. Roth, and T. M. Yarnall, “Comparisons of Cn2 measurements and power-in-fiber data from two long-path free-space optical communication experiments,” Proc. SPIE7814, 78140Z, (2010).
    [CrossRef]
  5. D. Giggenbach, W. Cowley, K. Grant, and N. Perlot, “Experimental verification of the limits of optical channel intensity reciprocity,” Appl. Opt.51(16), 3145–3152 (2012).
    [CrossRef] [PubMed]
  6. J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
    [CrossRef]
  7. T. H. Williams, R. J. Murphy, F. G. Walther, A. M. Volpicelli, W. E. Wilcox, and D. A. Crucioli, “A free-space terminal for fading channels,” Proc. SPIE7464, 74640W (2009).
    [CrossRef]
  8. J. A. Greco, “Design of the high-speed framing, FEC, and interleaving hardware used in a 5.4km free-space optical communication experiment,” Proc. SPIE7464, 746409 (2009).
    [CrossRef]
  9. F. G. Walther, S. Michael, R. R. Parenti, and J. A. Taylor, “Air-to-ground system demonstration design overview and results summary,” Proc. SPIE7814, 78140Y (2010).
    [CrossRef]
  10. G. S. Smith, “A direct derivation of a single-antenna reciprocity relation for the time domain,” IEEE Trans. Antenn. Propag.52(6), 1568–1577 (2004).
    [CrossRef]
  11. M. Guillaud, D. T. M. Slock, and R. Knopp, “A practical method for wireless channel reciprocity exploitation through relative calibration,” Proc. Eighth International Symposium on Signal Processing and Its Applications, Sydney Australia 1, 403–406 (2005).
  12. V. P. Aksenov, V. A. Banakh, V. M. Buldakov, V. L. Mironov, and O. V. Tikhomirova, “Distribution of fluctuations of light intensity behind the objective of a telescope after reflection in a turbulent atmosphere,” Sov. J. Quantum Electron.15(10), 1404–1406 (1985).
    [CrossRef]
  13. Y. A. Kravtsov, “New effects in wave propagation and scattering in random media (a mini review),” Appl. Opt.32(15), 2681–2691 (1993).
    [CrossRef] [PubMed]
  14. J. H. Shapiro and A. Puryear, “Reciprocity-enhanced optical communication through atmospheric turbulence - Part I: Reciprocity proofs and far-field power transfer optimization,” Proc. SPIE 8517, (in press).
  15. L. C. Andrews, R. L. Phillips, and C. Y. Hopen, Laser Beam Scintillation with Applications (SPIE Optical Engineering Press, Bellingham, WA, 2001).
  16. S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
    [CrossRef]

2012 (1)

2010 (2)

R. R. Parenti, S. Michael, J. M. Roth, and T. M. Yarnall, “Comparisons of Cn2 measurements and power-in-fiber data from two long-path free-space optical communication experiments,” Proc. SPIE7814, 78140Z, (2010).
[CrossRef]

F. G. Walther, S. Michael, R. R. Parenti, and J. A. Taylor, “Air-to-ground system demonstration design overview and results summary,” Proc. SPIE7814, 78140Y (2010).
[CrossRef]

2009 (4)

S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
[CrossRef]

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

T. H. Williams, R. J. Murphy, F. G. Walther, A. M. Volpicelli, W. E. Wilcox, and D. A. Crucioli, “A free-space terminal for fading channels,” Proc. SPIE7464, 74640W (2009).
[CrossRef]

J. A. Greco, “Design of the high-speed framing, FEC, and interleaving hardware used in a 5.4km free-space optical communication experiment,” Proc. SPIE7464, 746409 (2009).
[CrossRef]

2004 (1)

G. S. Smith, “A direct derivation of a single-antenna reciprocity relation for the time domain,” IEEE Trans. Antenn. Propag.52(6), 1568–1577 (2004).
[CrossRef]

1993 (1)

1985 (1)

V. P. Aksenov, V. A. Banakh, V. M. Buldakov, V. L. Mironov, and O. V. Tikhomirova, “Distribution of fluctuations of light intensity behind the objective of a telescope after reflection in a turbulent atmosphere,” Sov. J. Quantum Electron.15(10), 1404–1406 (1985).
[CrossRef]

1971 (2)

1896 (1)

H. A. Lorentz, “The theorem of poynting concerning the energy in the electromagnetic field and two general propositions concerning the propagation of light,” Versl. Kon. Akad. Wentensch. Amsterdam4, 176–187 (1896).

Aksenov, V. P.

V. P. Aksenov, V. A. Banakh, V. M. Buldakov, V. L. Mironov, and O. V. Tikhomirova, “Distribution of fluctuations of light intensity behind the objective of a telescope after reflection in a turbulent atmosphere,” Sov. J. Quantum Electron.15(10), 1404–1406 (1985).
[CrossRef]

Banakh, V. A.

V. P. Aksenov, V. A. Banakh, V. M. Buldakov, V. L. Mironov, and O. V. Tikhomirova, “Distribution of fluctuations of light intensity behind the objective of a telescope after reflection in a turbulent atmosphere,” Sov. J. Quantum Electron.15(10), 1404–1406 (1985).
[CrossRef]

Buldakov, V. M.

V. P. Aksenov, V. A. Banakh, V. M. Buldakov, V. L. Mironov, and O. V. Tikhomirova, “Distribution of fluctuations of light intensity behind the objective of a telescope after reflection in a turbulent atmosphere,” Sov. J. Quantum Electron.15(10), 1404–1406 (1985).
[CrossRef]

Cowley, W.

Crucioli, D. A.

T. H. Williams, R. J. Murphy, F. G. Walther, A. M. Volpicelli, W. E. Wilcox, and D. A. Crucioli, “A free-space terminal for fading channels,” Proc. SPIE7464, 74640W (2009).
[CrossRef]

Giggenbach, D.

Grant, K.

Greco, J. A.

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

J. A. Greco, “Design of the high-speed framing, FEC, and interleaving hardware used in a 5.4km free-space optical communication experiment,” Proc. SPIE7464, 746409 (2009).
[CrossRef]

Henion, S. R.

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

Kravtsov, Y. A.

Lorentz, H. A.

H. A. Lorentz, “The theorem of poynting concerning the energy in the electromagnetic field and two general propositions concerning the propagation of light,” Versl. Kon. Akad. Wentensch. Amsterdam4, 176–187 (1896).

Lutomirski, R. F.

Magliocco, R. J.

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

Michael, S.

R. R. Parenti, S. Michael, J. M. Roth, and T. M. Yarnall, “Comparisons of Cn2 measurements and power-in-fiber data from two long-path free-space optical communication experiments,” Proc. SPIE7814, 78140Z, (2010).
[CrossRef]

F. G. Walther, S. Michael, R. R. Parenti, and J. A. Taylor, “Air-to-ground system demonstration design overview and results summary,” Proc. SPIE7814, 78140Y (2010).
[CrossRef]

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
[CrossRef]

Mironov, V. L.

V. P. Aksenov, V. A. Banakh, V. M. Buldakov, V. L. Mironov, and O. V. Tikhomirova, “Distribution of fluctuations of light intensity behind the objective of a telescope after reflection in a turbulent atmosphere,” Sov. J. Quantum Electron.15(10), 1404–1406 (1985).
[CrossRef]

Moores, J. D.

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
[CrossRef]

Murphy, R. J.

S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
[CrossRef]

T. H. Williams, R. J. Murphy, F. G. Walther, A. M. Volpicelli, W. E. Wilcox, and D. A. Crucioli, “A free-space terminal for fading channels,” Proc. SPIE7464, 74640W (2009).
[CrossRef]

Parenti, R. R.

R. R. Parenti, S. Michael, J. M. Roth, and T. M. Yarnall, “Comparisons of Cn2 measurements and power-in-fiber data from two long-path free-space optical communication experiments,” Proc. SPIE7814, 78140Z, (2010).
[CrossRef]

F. G. Walther, S. Michael, R. R. Parenti, and J. A. Taylor, “Air-to-ground system demonstration design overview and results summary,” Proc. SPIE7814, 78140Y (2010).
[CrossRef]

S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
[CrossRef]

Perlot, N.

Roth, J. M.

R. R. Parenti, S. Michael, J. M. Roth, and T. M. Yarnall, “Comparisons of Cn2 measurements and power-in-fiber data from two long-path free-space optical communication experiments,” Proc. SPIE7814, 78140Z, (2010).
[CrossRef]

Shapiro, J. H.

Smith, G. S.

G. S. Smith, “A direct derivation of a single-antenna reciprocity relation for the time domain,” IEEE Trans. Antenn. Propag.52(6), 1568–1577 (2004).
[CrossRef]

Taylor, J. A.

F. G. Walther, S. Michael, R. R. Parenti, and J. A. Taylor, “Air-to-ground system demonstration design overview and results summary,” Proc. SPIE7814, 78140Y (2010).
[CrossRef]

Tikhomirova, O. V.

V. P. Aksenov, V. A. Banakh, V. M. Buldakov, V. L. Mironov, and O. V. Tikhomirova, “Distribution of fluctuations of light intensity behind the objective of a telescope after reflection in a turbulent atmosphere,” Sov. J. Quantum Electron.15(10), 1404–1406 (1985).
[CrossRef]

Volpicelli, A. M.

T. H. Williams, R. J. Murphy, F. G. Walther, A. M. Volpicelli, W. E. Wilcox, and D. A. Crucioli, “A free-space terminal for fading channels,” Proc. SPIE7464, 74640W (2009).
[CrossRef]

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
[CrossRef]

Walther, F. G.

F. G. Walther, S. Michael, R. R. Parenti, and J. A. Taylor, “Air-to-ground system demonstration design overview and results summary,” Proc. SPIE7814, 78140Y (2010).
[CrossRef]

T. H. Williams, R. J. Murphy, F. G. Walther, A. M. Volpicelli, W. E. Wilcox, and D. A. Crucioli, “A free-space terminal for fading channels,” Proc. SPIE7464, 74640W (2009).
[CrossRef]

S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
[CrossRef]

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

Wilcox, W. E.

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

T. H. Williams, R. J. Murphy, F. G. Walther, A. M. Volpicelli, W. E. Wilcox, and D. A. Crucioli, “A free-space terminal for fading channels,” Proc. SPIE7464, 74640W (2009).
[CrossRef]

S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
[CrossRef]

Williams, T. H.

T. H. Williams, R. J. Murphy, F. G. Walther, A. M. Volpicelli, W. E. Wilcox, and D. A. Crucioli, “A free-space terminal for fading channels,” Proc. SPIE7464, 74640W (2009).
[CrossRef]

Yarnall, T. M.

R. R. Parenti, S. Michael, J. M. Roth, and T. M. Yarnall, “Comparisons of Cn2 measurements and power-in-fiber data from two long-path free-space optical communication experiments,” Proc. SPIE7814, 78140Z, (2010).
[CrossRef]

Yura, H. T.

Appl. Opt. (3)

IEEE Trans. Antenn. Propag. (1)

G. S. Smith, “A direct derivation of a single-antenna reciprocity relation for the time domain,” IEEE Trans. Antenn. Propag.52(6), 1568–1577 (2004).
[CrossRef]

J. Opt. Soc. Am. (1)

Proc. SPIE (6)

R. R. Parenti, S. Michael, J. M. Roth, and T. M. Yarnall, “Comparisons of Cn2 measurements and power-in-fiber data from two long-path free-space optical communication experiments,” Proc. SPIE7814, 78140Z, (2010).
[CrossRef]

J. D. Moores, F. G. Walther, J. A. Greco, S. Michael, W. E. Wilcox, A. M. Volpicelli, R. J. Magliocco, and S. R. Henion, “Architecture overview and data summary of a 5.4 km free-space laser communications experiment,” Proc. SPIE7464, 746404 (2009).
[CrossRef]

T. H. Williams, R. J. Murphy, F. G. Walther, A. M. Volpicelli, W. E. Wilcox, and D. A. Crucioli, “A free-space terminal for fading channels,” Proc. SPIE7464, 74640W (2009).
[CrossRef]

J. A. Greco, “Design of the high-speed framing, FEC, and interleaving hardware used in a 5.4km free-space optical communication experiment,” Proc. SPIE7464, 746409 (2009).
[CrossRef]

F. G. Walther, S. Michael, R. R. Parenti, and J. A. Taylor, “Air-to-ground system demonstration design overview and results summary,” Proc. SPIE7814, 78140Y (2010).
[CrossRef]

S. Michael, R. R. Parenti, F. G. Walther, A. M. Volpicelli, J. D. Moores, W. E. Wilcox, and R. J. Murphy, “Comparison of scintillation measurements from a 5 km communication link to standard statistical models,” Proc. SPIE7324, 73240J (2009).
[CrossRef]

Sov. J. Quantum Electron. (1)

V. P. Aksenov, V. A. Banakh, V. M. Buldakov, V. L. Mironov, and O. V. Tikhomirova, “Distribution of fluctuations of light intensity behind the objective of a telescope after reflection in a turbulent atmosphere,” Sov. J. Quantum Electron.15(10), 1404–1406 (1985).
[CrossRef]

Versl. Kon. Akad. Wentensch. Amsterdam (1)

H. A. Lorentz, “The theorem of poynting concerning the energy in the electromagnetic field and two general propositions concerning the propagation of light,” Versl. Kon. Akad. Wentensch. Amsterdam4, 176–187 (1896).

Other (3)

M. Guillaud, D. T. M. Slock, and R. Knopp, “A practical method for wireless channel reciprocity exploitation through relative calibration,” Proc. Eighth International Symposium on Signal Processing and Its Applications, Sydney Australia 1, 403–406 (2005).

J. H. Shapiro and A. Puryear, “Reciprocity-enhanced optical communication through atmospheric turbulence - Part I: Reciprocity proofs and far-field power transfer optimization,” Proc. SPIE 8517, (in press).

L. C. Andrews, R. L. Phillips, and C. Y. Hopen, Laser Beam Scintillation with Applications (SPIE Optical Engineering Press, Bellingham, WA, 2001).

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Figures (10)

Fig. 1
Fig. 1

Downlink optical diagram showing the data-transmission beam (indicated by the arrows projecting from the left side of this figure) and upward-propagating tracking beams (indicated by the arrows projecting from the right side of this figure). Separate high-bandwidth trackers are used to stabilize the pointing direction of each of the laser sources and correct angle-of-arrival errors at the detectors. The reported correlation measurements relate to the outputs of the uplink and downlink power-in-fiber monitors.

Fig. 2
Fig. 2

Layout of the downlink transmitter showing the separation between the free-space optical module and the fiber-based electro-optical module. Tracking errors are sensed by the angle-of-arrival sensor and applied to the fast steering mirror (FSM). The tracking beams and downlink beams follow the same optical path in the optical module and tracking corrections are applied to both by the FSM.

Fig. 3
Fig. 3

In the FOCAL experiment the performance of a 2.7 Gb/s link between a transmitter mounted in a Twin Otter aircraft and a ground-based receiver was evaluated. For most of the tests, the aircraft was flown in a semicircular pattern centered on the location of the ground terminal. Tests were performed at ranges between 25 and 80 km.

Fig. 4
Fig. 4

Ground-level measurements of Cn2 collected on 10 November 2010. The values shown are typical of the turbulence conditions for the 2010 FOCAL experimental series.

Fig. 5
Fig. 5

Probability density function derived from measurements of the optical power collected by one of the four ground-based receivers during a 30 second interval (solid green curve). The overlay (black dashed curve) is a gamma-gamma model fit for α = β = 1.4. These data were obtained on 18 November 2010.

Fig. 6
Fig. 6

Representative correlation coefficient results from the downlink experiments conducted in the fall of 2009. The values correspond to the power-in-fiber correlations between the aircraft power monitor and the individual ground receivers; the ground-receiver sum correlation is shown in the last column. Since the received power from tracking transmitter #3 was effectively absent during these experiments, the theoretical upper limit on the sum-signal correlation coefficient was 0.87. These data were collected on 14 October 2009.

Fig. 7
Fig. 7

a. Two-dimensional probability density function for a typical data sample collected on 19 November 2010. The output of the aircraft power monitor is shown on the horizontal axis and the downlink output is indicated by the vertical axis. Figure 7b. Correlation coefficient as a function of time displacement of the aircraft power monitor time series relative to the downlink time series. A peak value of 0.99 was measured for this file at zero displacement.

Fig. 8
Fig. 8

Uplink/downlink time series correlation as a function of scintillation index (left chart) and propagation range (right chart). The histogram on the far right shows the overall likelihood of occurrence. The smallest of the values measured (95%) corresponded to unusually low signal-to-noise conditions that occurred when laser power was reduced to test system performance limitations.

Fig. 9
Fig. 9

Data-gating architecture based on a measurement of the collected optical power from the link's receiver beacon. A FIFO buffer on the transmit side holds data segments until they can be transmitted with a high probability of error-free detection. Not shown in this illustration is a mechanism for establishing an upper limit the input data rate based on the long-term average capacity of the free-space link.

Fig. 10
Fig. 10

Block diagram of a unidirectional transmitter that implements data frame gating based on measurements of the received optical power. This system incorporates forward error correction (FEC) to reduce the likelihood of errors, and a multiplexer (MUX) that transmits input data or blank frames, depending on the channel state.

Equations (3)

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p( I )= 2 α 2α Γ 2 ( α )μ ( I μ ) α1 K 0 { 2α I/μ } , where α= 1 σ I 2 +1 1
U( t )=a i=1 N p i u i ( t )D( t )=bq i=1 M d i ( t ) ,
ρ= ( U U ¯ )( D D ¯ ) ( U U ¯ ) 2 ( D D ¯ ) 2 = i=1 N p i M i=1 N p i 2 N M 1

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