Abstract

In a previous study, we developed a 1.6μm continuous-wave (cw) modulation laser absorption spectrometer system for CO2 sensing and demonstrated the measurement of small fluctuations in CO2 corresponding to a precision of 4parts per million (ppm) with a measurement interval of 32s. In this paper, we present the process to achieve this highly specific measurement by introducing important points, which have not been shown in the previous study. Following the results of preliminary experiments, we added a function for speckle averaging on the optical antenna unit. We additionally came up with some ideas to avoid the influences of etalon effects and polarization dependence in optical components. Because of the new functions, we realized a calibration precision of 0.006dB (rms), which corresponds to a CO2 concentration precision of less than 1ppm for a 2km path. We also analyzed the CO2 sensing performance after the improvements described above. The measured short time fluctuation of the differential absorption optical depth was reasonably close to that calculated using the carrier-to-noise ratio of the received signal.

© 2011 Optical Society of America

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References

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  1. J. Caron and Y. Durand, “Operating wavelength optimization for a spaceborne lidar measuring atmospheric CO2,” Appl. Opt. 48, 5413–5422 (2009).
    [CrossRef] [PubMed]
  2. D. Bruneau, F. Gibert, P. H. Flamant, and J. Pelon, “Complementary study of differential absorption lidar optimization in direct and heterodyne detections,” Appl. Opt. 45, 4898–4908(2006).
    [CrossRef] [PubMed]
  3. F. Gibert, M. Schmidt, J. Cuesta, P. Ciais, M. Ramonet, I. Xueref, E. Larmanou, and P. H. Flamant, “Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information,” J. Geophys. Res. 112, D10301(2007).
    [CrossRef]
  4. F. Gibert, P. H. Flamant, D. Bruneau, and C. Loth, “Two-micrometer heterodyne differential absorption lidar measurements of the atmospheric CO2 mixing ratio in the boundary layer,” Appl. Opt. 47, 944–956 (2008).
    [CrossRef] [PubMed]
  5. A. Amediek, A. Fix, M. Wirth, and G. Ehret, “Development of an OPO system at 1.57 μm for integrated path DIAL measurement of atmospheric carbon dioxide,” Appl. Phys. B 92, 295–302 (2008).
    [CrossRef]
  6. G. Eheret, C. Kiemle, M. Wirth, A. Amediek, A. Fix, and S. Houweling, “Space-borne remote sensing of CO2, CH4, and N2O by integrated path differential absorption lidar: a sensitivity analysis,” Appl. Phys. B 90, 593–608 (2008).
    [CrossRef]
  7. G. J. Koch, B. W. Barns, M. Petros, J. Y. Beyon, F. Amzajerdian, J. Yu, R. E. Davis, S. Ismail, S. Vay, M. J. Kavaya, and U. N. Singh, “Coherent differential absorption lidar measurements of CO2,” Appl. Opt. 43, 5092–5099 (2004).
    [CrossRef] [PubMed]
  8. G. J. Koch, J. Y. Beyon, F. Gibert, B. W. Barns, S. Ismail, M. Petros, P. J. Petzar, J. Yu, E. A. Modlin, K. J. Davis, and U. N. Singh, “Side-line tunable laser transmitter for differential absorption lidar measurements of CO2: design and application to atmospheric measurements,” Appl. Opt. 47, 944–956 (2008).
    [CrossRef] [PubMed]
  9. R. T. Menzies and D. M. Tratt, “Differential laser absorption spectrometry for global profiling of tropospheric carbon dioxide: selection of optimum sounding frequencies for high-precision measurements,” Appl. Opt. 42, 6569–6577 (2003).
    [CrossRef] [PubMed]
  10. G. D. Spiers, S. Geier, M. W. Phillips, and R. T. Menzies, “The JPL carbon dioxide laser absorption spectrometer,” Proceedings of the International Laser Radar Conference (2006), pp. 1031–1032.
  11. S. Kameyama and Y. Hirano, “Differential absorption lidar apparatus having multiplexed light signals with two wavelengths in a predetermined beam size and beam shape,” U. S. patent 7,361,922 (22 April 2008).
  12. S. Kameyama, M. Imaki, Y. Hirano, S. Ueno, D. Sakaizawa, S. Kawakami, and M. Nakajima, “Development of 1.6 μmcontinuous-wave modulation hard-target differential absorption lidar system for CO2 sensing,” Opt. Lett. 34, 1513–1515(2009).
    [CrossRef] [PubMed]
  13. P. Drobinski, P. H. Flamant, and P. Salamitou, “Spectral diversity technique for heterodyne Doppler lidar that uses hard target returns,” Appl. Opt. 39, 376–385 (2000).
    [CrossRef]
  14. K. D. Ridney, G. N. Pearson, and M. Harris, “Improved speckle statics in coherent differential absorption lidar with in-fiber wavelength multiplexing,” Appl. Opt. 40, 2017–2023 (2001).
    [CrossRef]
  15. D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
    [CrossRef]

2009

2008

G. J. Koch, J. Y. Beyon, F. Gibert, B. W. Barns, S. Ismail, M. Petros, P. J. Petzar, J. Yu, E. A. Modlin, K. J. Davis, and U. N. Singh, “Side-line tunable laser transmitter for differential absorption lidar measurements of CO2: design and application to atmospheric measurements,” Appl. Opt. 47, 944–956 (2008).
[CrossRef] [PubMed]

F. Gibert, P. H. Flamant, D. Bruneau, and C. Loth, “Two-micrometer heterodyne differential absorption lidar measurements of the atmospheric CO2 mixing ratio in the boundary layer,” Appl. Opt. 47, 944–956 (2008).
[CrossRef] [PubMed]

A. Amediek, A. Fix, M. Wirth, and G. Ehret, “Development of an OPO system at 1.57 μm for integrated path DIAL measurement of atmospheric carbon dioxide,” Appl. Phys. B 92, 295–302 (2008).
[CrossRef]

G. Eheret, C. Kiemle, M. Wirth, A. Amediek, A. Fix, and S. Houweling, “Space-borne remote sensing of CO2, CH4, and N2O by integrated path differential absorption lidar: a sensitivity analysis,” Appl. Phys. B 90, 593–608 (2008).
[CrossRef]

2007

F. Gibert, M. Schmidt, J. Cuesta, P. Ciais, M. Ramonet, I. Xueref, E. Larmanou, and P. H. Flamant, “Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information,” J. Geophys. Res. 112, D10301(2007).
[CrossRef]

2006

2004

2003

2001

2000

Amediek, A.

A. Amediek, A. Fix, M. Wirth, and G. Ehret, “Development of an OPO system at 1.57 μm for integrated path DIAL measurement of atmospheric carbon dioxide,” Appl. Phys. B 92, 295–302 (2008).
[CrossRef]

G. Eheret, C. Kiemle, M. Wirth, A. Amediek, A. Fix, and S. Houweling, “Space-borne remote sensing of CO2, CH4, and N2O by integrated path differential absorption lidar: a sensitivity analysis,” Appl. Phys. B 90, 593–608 (2008).
[CrossRef]

Amzajerdian, F.

Asai, K.

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

Barns, B. W.

Beyon, J. Y.

Bruneau, D.

Caron, J.

Ciais, P.

F. Gibert, M. Schmidt, J. Cuesta, P. Ciais, M. Ramonet, I. Xueref, E. Larmanou, and P. H. Flamant, “Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information,” J. Geophys. Res. 112, D10301(2007).
[CrossRef]

Cuesta, J.

F. Gibert, M. Schmidt, J. Cuesta, P. Ciais, M. Ramonet, I. Xueref, E. Larmanou, and P. H. Flamant, “Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information,” J. Geophys. Res. 112, D10301(2007).
[CrossRef]

Davis, K. J.

Davis, R. E.

Drobinski, P.

Durand, Y.

Eheret, G.

G. Eheret, C. Kiemle, M. Wirth, A. Amediek, A. Fix, and S. Houweling, “Space-borne remote sensing of CO2, CH4, and N2O by integrated path differential absorption lidar: a sensitivity analysis,” Appl. Phys. B 90, 593–608 (2008).
[CrossRef]

Ehret, G.

A. Amediek, A. Fix, M. Wirth, and G. Ehret, “Development of an OPO system at 1.57 μm for integrated path DIAL measurement of atmospheric carbon dioxide,” Appl. Phys. B 92, 295–302 (2008).
[CrossRef]

Fix, A.

A. Amediek, A. Fix, M. Wirth, and G. Ehret, “Development of an OPO system at 1.57 μm for integrated path DIAL measurement of atmospheric carbon dioxide,” Appl. Phys. B 92, 295–302 (2008).
[CrossRef]

G. Eheret, C. Kiemle, M. Wirth, A. Amediek, A. Fix, and S. Houweling, “Space-borne remote sensing of CO2, CH4, and N2O by integrated path differential absorption lidar: a sensitivity analysis,” Appl. Phys. B 90, 593–608 (2008).
[CrossRef]

Flamant, P. H.

Geier, S.

G. D. Spiers, S. Geier, M. W. Phillips, and R. T. Menzies, “The JPL carbon dioxide laser absorption spectrometer,” Proceedings of the International Laser Radar Conference (2006), pp. 1031–1032.

Gibert, F.

Harris, M.

Hirano, Y.

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

S. Kameyama, M. Imaki, Y. Hirano, S. Ueno, D. Sakaizawa, S. Kawakami, and M. Nakajima, “Development of 1.6 μmcontinuous-wave modulation hard-target differential absorption lidar system for CO2 sensing,” Opt. Lett. 34, 1513–1515(2009).
[CrossRef] [PubMed]

S. Kameyama and Y. Hirano, “Differential absorption lidar apparatus having multiplexed light signals with two wavelengths in a predetermined beam size and beam shape,” U. S. patent 7,361,922 (22 April 2008).

Houweling, S.

G. Eheret, C. Kiemle, M. Wirth, A. Amediek, A. Fix, and S. Houweling, “Space-borne remote sensing of CO2, CH4, and N2O by integrated path differential absorption lidar: a sensitivity analysis,” Appl. Phys. B 90, 593–608 (2008).
[CrossRef]

Imaki, M.

S. Kameyama, M. Imaki, Y. Hirano, S. Ueno, D. Sakaizawa, S. Kawakami, and M. Nakajima, “Development of 1.6 μmcontinuous-wave modulation hard-target differential absorption lidar system for CO2 sensing,” Opt. Lett. 34, 1513–1515(2009).
[CrossRef] [PubMed]

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

Ismail, S.

Kameyama, S.

S. Kameyama, M. Imaki, Y. Hirano, S. Ueno, D. Sakaizawa, S. Kawakami, and M. Nakajima, “Development of 1.6 μmcontinuous-wave modulation hard-target differential absorption lidar system for CO2 sensing,” Opt. Lett. 34, 1513–1515(2009).
[CrossRef] [PubMed]

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

S. Kameyama and Y. Hirano, “Differential absorption lidar apparatus having multiplexed light signals with two wavelengths in a predetermined beam size and beam shape,” U. S. patent 7,361,922 (22 April 2008).

Kavaya, M. J.

Kawakami, S.

S. Kameyama, M. Imaki, Y. Hirano, S. Ueno, D. Sakaizawa, S. Kawakami, and M. Nakajima, “Development of 1.6 μmcontinuous-wave modulation hard-target differential absorption lidar system for CO2 sensing,” Opt. Lett. 34, 1513–1515(2009).
[CrossRef] [PubMed]

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

Kiemle, C.

G. Eheret, C. Kiemle, M. Wirth, A. Amediek, A. Fix, and S. Houweling, “Space-borne remote sensing of CO2, CH4, and N2O by integrated path differential absorption lidar: a sensitivity analysis,” Appl. Phys. B 90, 593–608 (2008).
[CrossRef]

Koch, G. J.

Larmanou, E.

F. Gibert, M. Schmidt, J. Cuesta, P. Ciais, M. Ramonet, I. Xueref, E. Larmanou, and P. H. Flamant, “Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information,” J. Geophys. Res. 112, D10301(2007).
[CrossRef]

Loth, C.

Matsueda, H.

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

Menzies, R. T.

R. T. Menzies and D. M. Tratt, “Differential laser absorption spectrometry for global profiling of tropospheric carbon dioxide: selection of optimum sounding frequencies for high-precision measurements,” Appl. Opt. 42, 6569–6577 (2003).
[CrossRef] [PubMed]

G. D. Spiers, S. Geier, M. W. Phillips, and R. T. Menzies, “The JPL carbon dioxide laser absorption spectrometer,” Proceedings of the International Laser Radar Conference (2006), pp. 1031–1032.

Modlin, E. A.

Nakajima, M.

S. Kameyama, M. Imaki, Y. Hirano, S. Ueno, D. Sakaizawa, S. Kawakami, and M. Nakajima, “Development of 1.6 μmcontinuous-wave modulation hard-target differential absorption lidar system for CO2 sensing,” Opt. Lett. 34, 1513–1515(2009).
[CrossRef] [PubMed]

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

Pearson, G. N.

Pelon, J.

Petros, M.

Petzar, P. J.

Phillips, M. W.

G. D. Spiers, S. Geier, M. W. Phillips, and R. T. Menzies, “The JPL carbon dioxide laser absorption spectrometer,” Proceedings of the International Laser Radar Conference (2006), pp. 1031–1032.

Ramonet, M.

F. Gibert, M. Schmidt, J. Cuesta, P. Ciais, M. Ramonet, I. Xueref, E. Larmanou, and P. H. Flamant, “Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information,” J. Geophys. Res. 112, D10301(2007).
[CrossRef]

Ridney, K. D.

Sakaizawa, D.

S. Kameyama, M. Imaki, Y. Hirano, S. Ueno, D. Sakaizawa, S. Kawakami, and M. Nakajima, “Development of 1.6 μmcontinuous-wave modulation hard-target differential absorption lidar system for CO2 sensing,” Opt. Lett. 34, 1513–1515(2009).
[CrossRef] [PubMed]

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

Salamitou, P.

Sawa, Y.

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

Schmidt, M.

F. Gibert, M. Schmidt, J. Cuesta, P. Ciais, M. Ramonet, I. Xueref, E. Larmanou, and P. H. Flamant, “Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information,” J. Geophys. Res. 112, D10301(2007).
[CrossRef]

Singh, U. N.

Spiers, G. D.

G. D. Spiers, S. Geier, M. W. Phillips, and R. T. Menzies, “The JPL carbon dioxide laser absorption spectrometer,” Proceedings of the International Laser Radar Conference (2006), pp. 1031–1032.

Tratt, D. M.

Ueno, S.

S. Kameyama, M. Imaki, Y. Hirano, S. Ueno, D. Sakaizawa, S. Kawakami, and M. Nakajima, “Development of 1.6 μmcontinuous-wave modulation hard-target differential absorption lidar system for CO2 sensing,” Opt. Lett. 34, 1513–1515(2009).
[CrossRef] [PubMed]

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

Vay, S.

Wirth, M.

G. Eheret, C. Kiemle, M. Wirth, A. Amediek, A. Fix, and S. Houweling, “Space-borne remote sensing of CO2, CH4, and N2O by integrated path differential absorption lidar: a sensitivity analysis,” Appl. Phys. B 90, 593–608 (2008).
[CrossRef]

A. Amediek, A. Fix, M. Wirth, and G. Ehret, “Development of an OPO system at 1.57 μm for integrated path DIAL measurement of atmospheric carbon dioxide,” Appl. Phys. B 92, 295–302 (2008).
[CrossRef]

Xueref, I.

F. Gibert, M. Schmidt, J. Cuesta, P. Ciais, M. Ramonet, I. Xueref, E. Larmanou, and P. H. Flamant, “Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information,” J. Geophys. Res. 112, D10301(2007).
[CrossRef]

Yu, J.

Appl. Opt.

J. Caron and Y. Durand, “Operating wavelength optimization for a spaceborne lidar measuring atmospheric CO2,” Appl. Opt. 48, 5413–5422 (2009).
[CrossRef] [PubMed]

D. Bruneau, F. Gibert, P. H. Flamant, and J. Pelon, “Complementary study of differential absorption lidar optimization in direct and heterodyne detections,” Appl. Opt. 45, 4898–4908(2006).
[CrossRef] [PubMed]

F. Gibert, P. H. Flamant, D. Bruneau, and C. Loth, “Two-micrometer heterodyne differential absorption lidar measurements of the atmospheric CO2 mixing ratio in the boundary layer,” Appl. Opt. 47, 944–956 (2008).
[CrossRef] [PubMed]

G. J. Koch, B. W. Barns, M. Petros, J. Y. Beyon, F. Amzajerdian, J. Yu, R. E. Davis, S. Ismail, S. Vay, M. J. Kavaya, and U. N. Singh, “Coherent differential absorption lidar measurements of CO2,” Appl. Opt. 43, 5092–5099 (2004).
[CrossRef] [PubMed]

G. J. Koch, J. Y. Beyon, F. Gibert, B. W. Barns, S. Ismail, M. Petros, P. J. Petzar, J. Yu, E. A. Modlin, K. J. Davis, and U. N. Singh, “Side-line tunable laser transmitter for differential absorption lidar measurements of CO2: design and application to atmospheric measurements,” Appl. Opt. 47, 944–956 (2008).
[CrossRef] [PubMed]

R. T. Menzies and D. M. Tratt, “Differential laser absorption spectrometry for global profiling of tropospheric carbon dioxide: selection of optimum sounding frequencies for high-precision measurements,” Appl. Opt. 42, 6569–6577 (2003).
[CrossRef] [PubMed]

P. Drobinski, P. H. Flamant, and P. Salamitou, “Spectral diversity technique for heterodyne Doppler lidar that uses hard target returns,” Appl. Opt. 39, 376–385 (2000).
[CrossRef]

K. D. Ridney, G. N. Pearson, and M. Harris, “Improved speckle statics in coherent differential absorption lidar with in-fiber wavelength multiplexing,” Appl. Opt. 40, 2017–2023 (2001).
[CrossRef]

Appl. Phys. B

A. Amediek, A. Fix, M. Wirth, and G. Ehret, “Development of an OPO system at 1.57 μm for integrated path DIAL measurement of atmospheric carbon dioxide,” Appl. Phys. B 92, 295–302 (2008).
[CrossRef]

G. Eheret, C. Kiemle, M. Wirth, A. Amediek, A. Fix, and S. Houweling, “Space-borne remote sensing of CO2, CH4, and N2O by integrated path differential absorption lidar: a sensitivity analysis,” Appl. Phys. B 90, 593–608 (2008).
[CrossRef]

J. Geophys. Res.

F. Gibert, M. Schmidt, J. Cuesta, P. Ciais, M. Ramonet, I. Xueref, E. Larmanou, and P. H. Flamant, “Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information,” J. Geophys. Res. 112, D10301(2007).
[CrossRef]

Opt. Lett.

Proc. SPIE

D. Sakaizawa, S. Kawakami, M. Nakajima, Y. Sawa, H. Matsueda, K. Asai, S. Kameyama, M. Imaki, Y. Hirano, and S. Ueno, “Path-averaged atmospheric CO2 measurement using a 1.57 μm active remote sensor compared with multi-positioned in situ sensors,” Proc. SPIE 7460, 740006 (2009).
[CrossRef]

Other

G. D. Spiers, S. Geier, M. W. Phillips, and R. T. Menzies, “The JPL carbon dioxide laser absorption spectrometer,” Proceedings of the International Laser Radar Conference (2006), pp. 1031–1032.

S. Kameyama and Y. Hirano, “Differential absorption lidar apparatus having multiplexed light signals with two wavelengths in a predetermined beam size and beam shape,” U. S. patent 7,361,922 (22 April 2008).

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Figures (22)

Fig. 1
Fig. 1

CO 2 concentration measured during the first CO 2 sensing trial.

Fig. 2
Fig. 2

System configuration of 1.6 μm cw modulation LAS system used in the first trial.

Fig. 3
Fig. 3

Schematic of the setup for preliminary experiments: MON, photodetector used in the monitoring port and REC, photodetector used in the receiving port.

Fig. 4
Fig. 4

Experimental setup for confirming the influence of the speckle effect on calibration precision.

Fig. 5
Fig. 5

Time record of measured intensity ratio for wavelength differences of (a) 0.3 (solid curve), 2 (dashed curve), and 10 pm (dotted curve) and (b) 50 (solid curve), 100 (dotted curve), and 200 pm (dotted curve).

Fig. 6
Fig. 6

Experimental setup for confirming the influence of the optical attenuator on calibration precision.

Fig. 7
Fig. 7

Time record of measured intensity ratio measured with the experimental setup shown in Fig. 6.

Fig. 8
Fig. 8

Same experimental setup as Fig. 6, but the attenuator was changed to a splice-type SMF tap divider.

Fig. 9
Fig. 9

Time record of measured intensity ratio measured with the experimental setup shown in Fig. 8.

Fig. 10
Fig. 10

Experimental setup for confirming the influence of the optical filter on calibration precision.

Fig. 11
Fig. 11

Time record of measured intensity ratio measured with the experimental setup shown in Fig. 10.

Fig. 12
Fig. 12

Time record of measured intensity ratio and room temperature measured with the experimental setup shown in Fig. 8. In the regions encircled by the dotted line, the input fiber of the photodiode for monitoring was squeezed.

Fig. 13
Fig. 13

Experimental setup for confirming the influence of the monitoring photodetector on calibration precision.

Fig. 14
Fig. 14

Time record of measured intensity ratio and room temperature measured with the experimental setup shown in Fig. 13.

Fig. 15
Fig. 15

Same results shown in Fig. 14, but the monitoring photodetector was TE cooled.

Fig. 16
Fig. 16

Experimental setup for confirming the influence of the MMF for the receiving port on calibration precision.

Fig. 17
Fig. 17

Time record of the measured intensity ratio and room temperature measured with the experimental setup shown in Fig. 16.

Fig. 18
Fig. 18

System configuration refined after the preliminary experiments.

Fig. 19
Fig. 19

Results of the system calibration test. In the denoted region, polarization scrambling or beam dither was turned OFF.

Fig. 20
Fig. 20

Time records of CO 2 concentration measured by the improved system and the in situ CO 2 sensor.

Fig. 21
Fig. 21

CNR of the monitoring and receiving port signals for ON and OFF wavelengths obtained in the same experiment shown in Fig. 20.

Fig. 22
Fig. 22

Short time fluctuation of the DAOD obtained in the same experiment shown in Fig. 20: solid curve, calculated result when there is no turbulence; shaded curve, calculated result at the CNR limit; and dotted curve, measured result.

Tables (1)

Tables Icon

Table 1 System Parameters

Equations (6)

Equations on this page are rendered with MathJax. Learn more.

I R = | 20 · Log 10 [ exp ( - 2 · O D · L · ρ T ρ B ) ] | ,
Δ δ = 1 2 ( 1 SNR ON R + 1 SNR OFF R + 1 SNR ON M + 1 SNR OFF M ) ,
SNR ON , OFF = CNR ON , OFF R 1 + CNR ON , OFF R SNR S ( 1 + 1 + SNR S SNR ON , OFF M ) ,
SNR S = M S · M I ,
M S 1 + ( π D θ T 4 λ ) 2 ,
M I θ H · θ E θ T 2 ,

Metrics