Abstract

In addition to a conventional phase α the interference signal of a sinusoidal-wavelength-scanning interferometer has a phase-modulation amplitude Z b that is proportional to the optical path difference L and amplitude b of the wavelength scan. L and b are controlled by a double feedback system so that the phase α and the amplitude Z b are kept at 3π/2 and π, respectively. The voltage applied to a device that displaces a reference mirror to change the optical path difference becomes a ruler with scales smaller than a wavelength. Voltage applied to a device that determines the amplitude of the wavelength scan becomes a ruler marking every wavelength. These two rulers enable one to measure an absolute distance longer than a wavelength in real time.

© 2002 Optical Society of America

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References

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    [CrossRef]
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  4. O. Sasaki, N. Murata, K. Akiyama, T. Suzuki, “Sinusoidal wavelength-scanning interferometers using a superluminescent diode,” in Applications: Interferometry ’99, W. P. O. Jüptner, K. Patorski, eds., Proc. SPIE3745, 196–204 (1999).
    [CrossRef]
  5. O. Sasaki, N. Murata, T. Suzuki, “Sinusoidal wavelength-scanning interferometer with a superluminescent diode for step-profile measurement,” Appl. Opt. 39, 4589–4592 (2000).
    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]

2000

1998

X. Dai, K. Seta, “High-accuracy absolute distance measurement by means of wavelength scanning heterodyne interferometry,” Meas. Sci. Technol. 9, 1013–1035 (1998).

1995

1989

1986

Akiyama, K.

O. Sasaki, N. Murata, K. Akiyama, T. Suzuki, “Sinusoidal wavelength-scanning interferometers using a superluminescent diode,” in Applications: Interferometry ’99, W. P. O. Jüptner, K. Patorski, eds., Proc. SPIE3745, 196–204 (1999).
[CrossRef]

Dai, X.

X. Dai, K. Seta, “High-accuracy absolute distance measurement by means of wavelength scanning heterodyne interferometry,” Meas. Sci. Technol. 9, 1013–1035 (1998).

Ishii, Y.

Kobayashi, K.

Maruyama, T.

Murata, N.

O. Sasaki, N. Murata, T. Suzuki, “Sinusoidal wavelength-scanning interferometer with a superluminescent diode for step-profile measurement,” Appl. Opt. 39, 4589–4592 (2000).
[CrossRef]

O. Sasaki, N. Murata, K. Akiyama, T. Suzuki, “Sinusoidal wavelength-scanning interferometers using a superluminescent diode,” in Applications: Interferometry ’99, W. P. O. Jüptner, K. Patorski, eds., Proc. SPIE3745, 196–204 (1999).
[CrossRef]

Okazaki, H.

Onodera, R.

Sasaki, O.

Seta, K.

X. Dai, K. Seta, “High-accuracy absolute distance measurement by means of wavelength scanning heterodyne interferometry,” Meas. Sci. Technol. 9, 1013–1035 (1998).

Suzuki, T.

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Figures (8)

Fig. 1
Fig. 1

SWS interferometer for real-time distance measurement: BS1, BS2, beam splitters; DA, divider; OSC, oscillator.

Fig. 2
Fig. 2

Block diagram of feedback signal generator 1: MA, multiplier; LF, low-pass filter.

Fig. 3
Fig. 3

Change in the OPD by feedback control, which keeps phase α at 3π/2.

Fig. 4
Fig. 4

Block diagram of feedback signal generator 2: SH, sample holder; SB, subtractor.

Fig. 5
Fig. 5

Stable points of V b .

Fig. 6
Fig. 6

Stability of the stable points with time: (a) N = 1, 2, and 3, (b) N = 80, 81, and 82.

Fig. 7
Fig. 7

Relationship between V b and b.

Fig. 8
Fig. 8

Values of m - m c at the stable points of V b shown in Fig. 5.

Tables (2)

Tables Icon

Table 1 Results of Measurements with a Value of b

Tables Icon

Table 2 Results of Measurement with a Value of m

Equations (12)

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λt=λ0+b cosωbt.
St=SDt/IMt=A+B cosZb cos ωbt+α,
Zb=2πb/λ02L,
α=-2π/λ0L,
A1=BJ2Zbcos α=g cos α,
Lz=L-Lα=3λ0/4+mλ0.
St=A-B sinZb cos ωbt,
Zb=2πb/λ02Lz.
A2=S-1-S1=2B sin Zb
b=λ02/2Lz=2λ0/4m+3.
mc=Lz-3λ0/4/λ0.
L=3λ0/4+mλ0+Lα.

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