Abstract

Feedback phenomena in lasers induce modulation signals that can be used for ranging and velocimetry. The modulation depth of a backscatter-modulated semiconductor laser diode is considerably enhanced by operating the diode near the lasing threshold. In the present work an external cavity is used to maintain a spectral linewidth of less than 1 MHz in a diode running at 2.5% of its rated power of 30 mW, resulting in a modulation depth enhancement by a factor of 30 over the high-power limit. Coherent velocimetry has been performed for targets at a distance of 50 m, or 20 times farther than the previously published operational range for backscatter-modulated laser diodes. Light power of less than 10 pW at the collection aperture produces useful modulation signals.

© 1989 Optical Society of America

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References

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  1. J. H. Churnside, Appl. Opt. 23, 61 (1984).
    [CrossRef] [PubMed]
  2. J. H. Churnside, Appl. Opt. 23, 2097 (1984).
    [CrossRef] [PubMed]
  3. S. Shinohara, A. Mochizuki, H. Yoshida, M. Sumio, Appl. Opt. 25, 1417 (1986).
    [CrossRef] [PubMed]
  4. E. T. Shimizu, Appl. Opt. 26, 4541 (1987).
    [CrossRef] [PubMed]
  5. H. W. Jentink, F. F. M. de Mul, H. E. Suichies, J. G. Aarnoudse, J. Greve, Appl. Opt. 27, 379 (1988).
    [CrossRef] [PubMed]
  6. G. Beheim, K. Fritsch, Appl. Opt. 25, 1439 (1986).
    [CrossRef] [PubMed]
  7. P. J. de Groot, G. M. Gallatin, S. H. Macomber, Appl. Opt. 27, 4475 (1988).
    [CrossRef] [PubMed]
  8. R. Lang, K. Kobayashi, IEEE J. Quantum Electron. QE-16, 347 (1980).
    [CrossRef]
  9. P. Zorabedian, W. R. Trutna, L. S. Cutler, IEEE J. Quantum Electron. QE-23, 1855 (1987).
    [CrossRef]
  10. G. A. Acket, D. Lenstra, A. J. den Boef, B. H. Verbeek, IEEE J. Quantum Electron. QE-20, 1163 (1984).
    [CrossRef]

1988

1987

E. T. Shimizu, Appl. Opt. 26, 4541 (1987).
[CrossRef] [PubMed]

P. Zorabedian, W. R. Trutna, L. S. Cutler, IEEE J. Quantum Electron. QE-23, 1855 (1987).
[CrossRef]

1986

1984

J. H. Churnside, Appl. Opt. 23, 61 (1984).
[CrossRef] [PubMed]

J. H. Churnside, Appl. Opt. 23, 2097 (1984).
[CrossRef] [PubMed]

G. A. Acket, D. Lenstra, A. J. den Boef, B. H. Verbeek, IEEE J. Quantum Electron. QE-20, 1163 (1984).
[CrossRef]

1980

R. Lang, K. Kobayashi, IEEE J. Quantum Electron. QE-16, 347 (1980).
[CrossRef]

Aarnoudse, J. G.

Acket, G. A.

G. A. Acket, D. Lenstra, A. J. den Boef, B. H. Verbeek, IEEE J. Quantum Electron. QE-20, 1163 (1984).
[CrossRef]

Beheim, G.

Churnside, J. H.

Cutler, L. S.

P. Zorabedian, W. R. Trutna, L. S. Cutler, IEEE J. Quantum Electron. QE-23, 1855 (1987).
[CrossRef]

de Groot, P. J.

de Mul, F. F. M.

den Boef, A. J.

G. A. Acket, D. Lenstra, A. J. den Boef, B. H. Verbeek, IEEE J. Quantum Electron. QE-20, 1163 (1984).
[CrossRef]

Fritsch, K.

Gallatin, G. M.

Greve, J.

Jentink, H. W.

Kobayashi, K.

R. Lang, K. Kobayashi, IEEE J. Quantum Electron. QE-16, 347 (1980).
[CrossRef]

Lang, R.

R. Lang, K. Kobayashi, IEEE J. Quantum Electron. QE-16, 347 (1980).
[CrossRef]

Lenstra, D.

G. A. Acket, D. Lenstra, A. J. den Boef, B. H. Verbeek, IEEE J. Quantum Electron. QE-20, 1163 (1984).
[CrossRef]

Macomber, S. H.

Mochizuki, A.

Shimizu, E. T.

Shinohara, S.

Suichies, H. E.

Sumio, M.

Trutna, W. R.

P. Zorabedian, W. R. Trutna, L. S. Cutler, IEEE J. Quantum Electron. QE-23, 1855 (1987).
[CrossRef]

Verbeek, B. H.

G. A. Acket, D. Lenstra, A. J. den Boef, B. H. Verbeek, IEEE J. Quantum Electron. QE-20, 1163 (1984).
[CrossRef]

Yoshida, H.

Zorabedian, P.

P. Zorabedian, W. R. Trutna, L. S. Cutler, IEEE J. Quantum Electron. QE-23, 1855 (1987).
[CrossRef]

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Figures (3)

Fig. 1
Fig. 1

Block diagram of the experimental setup used to demonstrate the backscatter-modulated external-cavity laser-diode velocimeter. The optical spectrum analyzer monitors the lasing properties of the system and ensures single-mode operation.

Fig. 2
Fig. 2

Spectrum analysis of the modulation signal obtained using backscatter modulation with an external-cavity laser diode. The target distance was 30 m. The main peak is at the 40-kHz fundamental frequency of the velocimetry signal.

Fig. 3
Fig. 3

Modulation depth as a function of pump current for the setup shown in Fig. 1. The theory curve was generated from relation (5) for a coupling efficiency of 18%. The modulation depth enhancement near threshold is characteristic of backscatter modulation and does not occur in a conventional homodyne detection system.

Equations (6)

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f = 2 V / λ ,
P = κ ( J J th 1 ) ,
Δ P = κ ( J J th ) ( Δ J th J th ) .
W B = ( Δ P ) max P ( J / J th J / J th 1 ) ,
W B ( κ P + 1 ) .
W H 2 r .

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