Abstract

The multiheterodyne beatnote between two frequency combs having pulses sliding one with respect to another is used to perform spectrally resolved ranging of diffuse reflectors at short distances. The sliding comb sources are generated using one mode-locked laser and a two-beam interferometer, but two properly controlled lasers could be used as well. A pseudo-random binary modulation of the pulses is used to increase the non-ambiguous range. Ranging with a spatial resolution of 21 cm and a spectral resolution of 10 cm−1 over a 200 cm−1 spectral range is demonstrated.

© 2010 Optical Society of America

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References

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  1. F. Keilmann, C. Gohle, and R. Holzwarth, “Time-domain mid-infrared frequency-comb spectrometer,” Opt. Lett. 29, 1542–1544 (2004).
    [CrossRef] [PubMed]
  2. I. Coddington, W. C. Swann, and N. R. Newbury, “Coherent Multiheterodyne Spectroscopy Using Stabilized Optical Frequency Combs,” Phys. Rev. Lett. 100, 013,902 1–4 (2008).
    [CrossRef]
  3. P. Giaccari, J.-D. Deschenes, P. Saucier, J. Genest, and P. Tremblay, “Active Fourier-transform spectroscopy combining the direct RF beating of two fiber-based mode-locked lasers with a novel referencing method,” Opt. Express 16, 4347–4365 (2008).
    [CrossRef] [PubMed]
  4. I. Coddington, W. C. Swann, L. Nenadovic, and N. R. Newbury, “Rapid and precise absolute distance measurements at long range,” Nature Photonics 3, 351–356 (2009).
    [CrossRef]
  5. M. Cui, M. G. Zeitouny, N. Bhattacharya, S. A. van den Berg, H. P. Urbach, J. J. M. Braat, “High-accuracy long-distance measurements in air with a frequency comb laser,” Opt. Lett. 34, 1982–1984 (2009).
    [CrossRef] [PubMed]
  6. C. Nagasawa, M. Abo, H. Yamamoto, and O. Uchino, “Random modulation cw lidar using new random sequence,” Appl. Opt. 29, 1466–1470 (1990).
    [CrossRef] [PubMed]
  7. S. W. Golomb and G. Gong, Signal Design for Good Correlation: For Wireless Communication, Cryptography, and Radar, 1st ed. (Cambridge University press, 2005).
    [CrossRef]

2009 (2)

I. Coddington, W. C. Swann, L. Nenadovic, and N. R. Newbury, “Rapid and precise absolute distance measurements at long range,” Nature Photonics 3, 351–356 (2009).
[CrossRef]

M. Cui, M. G. Zeitouny, N. Bhattacharya, S. A. van den Berg, H. P. Urbach, J. J. M. Braat, “High-accuracy long-distance measurements in air with a frequency comb laser,” Opt. Lett. 34, 1982–1984 (2009).
[CrossRef] [PubMed]

2008 (1)

2004 (1)

1990 (1)

Abo, M.

Bhattacharya, N.

Braat, J. J. M.

Coddington, I.

I. Coddington, W. C. Swann, L. Nenadovic, and N. R. Newbury, “Rapid and precise absolute distance measurements at long range,” Nature Photonics 3, 351–356 (2009).
[CrossRef]

Cui, M.

Giaccari, P.

Gohle, C.

Holzwarth, R.

Keilmann, F.

Nagasawa, C.

Nenadovic, L.

I. Coddington, W. C. Swann, L. Nenadovic, and N. R. Newbury, “Rapid and precise absolute distance measurements at long range,” Nature Photonics 3, 351–356 (2009).
[CrossRef]

Newbury, N. R.

I. Coddington, W. C. Swann, L. Nenadovic, and N. R. Newbury, “Rapid and precise absolute distance measurements at long range,” Nature Photonics 3, 351–356 (2009).
[CrossRef]

Swann, W. C.

I. Coddington, W. C. Swann, L. Nenadovic, and N. R. Newbury, “Rapid and precise absolute distance measurements at long range,” Nature Photonics 3, 351–356 (2009).
[CrossRef]

Uchino, O.

Urbach, H. P.

van den Berg, S. A.

Yamamoto, H.

Zeitouny, M. G.

Appl. Opt. (1)

Nature Photonics (1)

I. Coddington, W. C. Swann, L. Nenadovic, and N. R. Newbury, “Rapid and precise absolute distance measurements at long range,” Nature Photonics 3, 351–356 (2009).
[CrossRef]

Opt. Express (1)

Opt. Lett. (2)

Other (2)

S. W. Golomb and G. Gong, Signal Design for Good Correlation: For Wireless Communication, Cryptography, and Radar, 1st ed. (Cambridge University press, 2005).
[CrossRef]

I. Coddington, W. C. Swann, and N. R. Newbury, “Coherent Multiheterodyne Spectroscopy Using Stabilized Optical Frequency Combs,” Phys. Rev. Lett. 100, 013,902 1–4 (2008).
[CrossRef]

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Figures (9)

Fig. 1.
Fig. 1.

Pseudo-random binary modulation of the pulses to increase the non-ambiguous range. PC stands for polarization controller. The pulse generator conditions the electrical pulse train issued by the detector. The Bit Error Rate Test Set (BERT) generates the wanted PRBS. Full setup, with interferometer and telescope is provided on Fig. 4.

Fig. 2.
Fig. 2.

Two sequences corresponding to a relative distance of 12:2 m. Blue: Reference specular reflector at 4:2 m, Red: Diffuse reflector at 16 m. Matching the sequence patterns allows to increase the non-ambiguous range.

Fig. 3.
Fig. 3.

A circular cross-correlation between the received trace and the sent (or reference) sequence yields a ranging trace over an expanded non-ambiguous range of 190:5 m, specular reflector at 10:5 m.

Fig. 4.
Fig. 4.

Complete setup for spectrally resolved ranging system. A comb is modulated by a maximal length PRBS sequence. The pulses are then stretched with SMF fiber and amplified. A reference sequence is recorded before final amplification, collimation (B. Ex. stands for Beam expander) and interferometric modulation. Optical signals are represented with thick lines, electrical signals with thin lines.

Fig. 5.
Fig. 5.

Modulated cross-correlated pulses yield interferograms at increasing distances. One interferogram is measured for each 3 cm spatial depth. Spatial resolution is however 21 cm. Specular reflector located at 6.4 m. The optical path difference scale is on 632.8 nm fringes

Fig. 6.
Fig. 6.

Spectrally resolved ranging trace, with a specular reflector at 6.4 m. One spectrum is obtained for each 3 cm spatial depth. The spatial resolution is 21 cm. Signal to noise limitation is seen in the spectrum at the reflector distance (6.4 m) while dynamic range limitation due to the cross-correlation is seen for all distances at the wavenumber having the peak signal (6415 cm−1). More details on the two next figures.

Fig. 7.
Fig. 7.

Slice of Fig. 6 showing the spectrum reflected at 6.4 m, the target distance. Spectral resolution is 10 cm−1

Fig. 8.
Fig. 8.

Slice of Fig. 6 showing the ranging information at the peak signal wavenumber (6415 cm−1). The structured noise floor is arising from the cross-correlation dynamic range limitation: 10*log10[(N-1)/2] = 18 dB, with N=127. Spatial resolution is 21 cm.

Fig. 9.
Fig. 9.

Average of 1000 spectra reflected by a diffuse target at 6.4 m, spatial resolution is 21 cm, spectral resolution 10 cm−1.

Equations (6)

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C [ n ] = M [ n ] M [ n ] = { N n = 0 1 n 0 ,
S [ n ] = Γ 0.5 ( M [ n ] + 1 ) ,
T [ n ] = M [ n ] S [ n ]
= 0.5 Γ { M [ n ] ( M [ n ] + 1 ) }
= 0.5 Γ { M [ n ] M [ n ] + M [ n ] 1 } .
T [ n ] = { Γ ( N 1 ) 2 n = 0 Γ n 0

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