Abstract

A method to digitize the intensity of ultrashort laser pulses for high-speed optical signal processing is described. This digitization was based on the spectral broadening of a weak probe (carrier) pulse by a more intense pump (signal) pulse through the nonlinear optical process of cross-phase modulation (XPM). The signal pulse intensity was varied to generate different spectral widths that can be encoded into digital form. Using a 50-ps time-divided multiplexing pulse train with a waveguide splitter, combiner, and an array of fibers with variable lengths, a unary XPM encoding approach is demonstrated. The spectral encoding scheme can be used to achieve a 5-GHz sampling rate at a 16-level accuracy.

© 1997 Optical Society of America

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    [CrossRef]
  4. S. Kawanishi, H. Takara, K. Uchiyama, M. Saruwatari, T. Kitoh, “Fully time-division multiplexed 100 Gbits/s optical transmission experiment,” Electron. Lett. 29, 2211–2212 (1993).
    [CrossRef]
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    [CrossRef] [PubMed]

1995 (1)

1994 (1)

1993 (1)

S. Kawanishi, H. Takara, K. Uchiyama, M. Saruwatari, T. Kitoh, “Fully time-division multiplexed 100 Gbits/s optical transmission experiment,” Electron. Lett. 29, 2211–2212 (1993).
[CrossRef]

1992 (3)

T. Morioka, K. Mori, M. Saruwatari, “Ultrafast polarization independent optical de-multiplexer using optical carrier frequency shift through cross-phase-modulation,” Electron. Lett. 28, 1070–1072 (1992).
[CrossRef]

J.-M. Jeong, M. E. Marhic, “All optical analog to digital and digital to analog conversion implemented by a nonlinear fiber interferometer,” Opt. Commun. 91, 115–122 (1992).
[CrossRef]

B. L. Shoop, J. W. Goodman, “Optical oversampled analog-to-digital conversion,” Appl. Opt. 31, 5654–5660 (1992).
[CrossRef] [PubMed]

1991 (2)

M. E. Marhic, C. H. Hsia, J.-M. Jeong, “Optical amplification in a nonlinear fiber interferometer,” Electron. Lett. 27, 210–211 (1991).
[CrossRef]

J.-M. Jeong, M. E. Marhic, “All optical logic gate based on cross-phase-modulation of a nonlinear fiber interferometer,” Opt. Commun. 85, 430–436 (1991).
[CrossRef]

1989 (3)

1988 (1)

1987 (1)

1986 (2)

1984 (1)

1983 (1)

1978 (1)

R. H. Stolen, C. Lin, “Self-phase-modulation in silica optical fibers,” Phys. Rev. A 17, 1448–1453 (1978).
[CrossRef]

1970 (1)

R. R. Alfano, S. L. Shapiro, “Observation of self-phase-modulation and small scale filaments in crystals and glasses,” Phys. Rev. Lett. 24, 592–594 (1970).
[CrossRef]

Agrawal, G. P.

Alfano, R. R.

Baldeck, P. L.

Chen, J. T.

Flavin, M. A.

Fork, R.

Fujimoto, J. G.

Goodman, J. W.

Haus, H. A.

Heritage, J. P.

Herliman, C.

Ho, P. P.

Horner, J. L.

Hsia, C. H.

M. E. Marhic, C. H. Hsia, J.-M. Jeong, “Optical amplification in a nonlinear fiber interferometer,” Electron. Lett. 27, 210–211 (1991).
[CrossRef]

Islam, M. N.

Jeong, J.-M.

J.-M. Jeong, M. E. Marhic, “All optical analog to digital and digital to analog conversion implemented by a nonlinear fiber interferometer,” Opt. Commun. 91, 115–122 (1992).
[CrossRef]

J.-M. Jeong, M. E. Marhic, “All optical logic gate based on cross-phase-modulation of a nonlinear fiber interferometer,” Opt. Commun. 85, 430–436 (1991).
[CrossRef]

M. E. Marhic, C. H. Hsia, J.-M. Jeong, “Optical amplification in a nonlinear fiber interferometer,” Electron. Lett. 27, 210–211 (1991).
[CrossRef]

Jimbo, T.

Kawanishi, S.

S. Kawanishi, H. Takara, K. Uchiyama, M. Saruwatari, T. Kitoh, “Fully time-division multiplexed 100 Gbits/s optical transmission experiment,” Electron. Lett. 29, 2211–2212 (1993).
[CrossRef]

Kimura, Y.

Y. Kimura, K. I. Kitayama, N. Shibata, S. Seikai, “All-fiber-optic logic and gate,” Electron. Lett. 22, 277–278 (1986).
[CrossRef]

Kitayama, K. I.

Y. Kimura, K. I. Kitayama, N. Shibata, S. Seikai, “All-fiber-optic logic and gate,” Electron. Lett. 22, 277–278 (1986).
[CrossRef]

Kitoh, T.

S. Kawanishi, H. Takara, K. Uchiyama, M. Saruwatari, T. Kitoh, “Fully time-division multiplexed 100 Gbits/s optical transmission experiment,” Electron. Lett. 29, 2211–2212 (1993).
[CrossRef]

LaGasse, M. J.

Li, Q. X.

Lin, C.

R. H. Stolen, C. Lin, “Self-phase-modulation in silica optical fibers,” Phys. Rev. A 17, 1448–1453 (1978).
[CrossRef]

Liu, Disa

P. P. Ho, Q. Z. Wang, Q. D. Liu, Disa Liu, R. R. Alfano, “High resolution spectra of cross-phase-modulation for an A/D Converter,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. SPIE2155, 37–40 (1994).
[CrossRef]

Liu, Q. D.

Q. D. Liu, J. T. Chen, Q. Z. Wang, P. P. Ho, R. R. Alfano, “Single-pulse degenerate-cross-phase modulation in a single-mode optical fiber,” Opt. Lett. 20, 542–544 (1995).
[CrossRef] [PubMed]

Q. Z. Wang, Q. D. Liu, E. Walge, P. P. Ho, R. R. Alfano, “High resolution spectra of cross-phase-modulation in fibers,” Opt. Lett. 19, 1636–1638 (1994).
[CrossRef] [PubMed]

P. P. Ho, Q. Z. Wang, Q. D. Liu, Disa Liu, R. R. Alfano, “High resolution spectra of cross-phase-modulation for an A/D Converter,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. SPIE2155, 37–40 (1994).
[CrossRef]

Liu-wong, D.

Manassah, J. T.

Marhic, M. E.

J.-M. Jeong, M. E. Marhic, “All optical analog to digital and digital to analog conversion implemented by a nonlinear fiber interferometer,” Opt. Commun. 91, 115–122 (1992).
[CrossRef]

J.-M. Jeong, M. E. Marhic, “All optical logic gate based on cross-phase-modulation of a nonlinear fiber interferometer,” Opt. Commun. 85, 430–436 (1991).
[CrossRef]

M. E. Marhic, C. H. Hsia, J.-M. Jeong, “Optical amplification in a nonlinear fiber interferometer,” Electron. Lett. 27, 210–211 (1991).
[CrossRef]

Mollenauer, L. F.

Mori, K.

T. Morioka, K. Mori, M. Saruwatari, “Ultrafast polarization independent optical de-multiplexer using optical carrier frequency shift through cross-phase-modulation,” Electron. Lett. 28, 1070–1072 (1992).
[CrossRef]

Morioka, T.

T. Morioka, K. Mori, M. Saruwatari, “Ultrafast polarization independent optical de-multiplexer using optical carrier frequency shift through cross-phase-modulation,” Electron. Lett. 28, 1070–1072 (1992).
[CrossRef]

Salehi, J. A.

Saruwatari, M.

S. Kawanishi, H. Takara, K. Uchiyama, M. Saruwatari, T. Kitoh, “Fully time-division multiplexed 100 Gbits/s optical transmission experiment,” Electron. Lett. 29, 2211–2212 (1993).
[CrossRef]

T. Morioka, K. Mori, M. Saruwatari, “Ultrafast polarization independent optical de-multiplexer using optical carrier frequency shift through cross-phase-modulation,” Electron. Lett. 28, 1070–1072 (1992).
[CrossRef]

Seikai, S.

Y. Kimura, K. I. Kitayama, N. Shibata, S. Seikai, “All-fiber-optic logic and gate,” Electron. Lett. 22, 277–278 (1986).
[CrossRef]

Shang, H. T.

Shank, C.

Shapiro, S. L.

R. R. Alfano, S. L. Shapiro, “Observation of self-phase-modulation and small scale filaments in crystals and glasses,” Phys. Rev. Lett. 24, 592–594 (1970).
[CrossRef]

Shen, Y. R.

Shibata, N.

Y. Kimura, K. I. Kitayama, N. Shibata, S. Seikai, “All-fiber-optic logic and gate,” Electron. Lett. 22, 277–278 (1986).
[CrossRef]

Shoop, B. L.

Simpson, J. R.

Stolen, R. H.

Takara, H.

S. Kawanishi, H. Takara, K. Uchiyama, M. Saruwatari, T. Kitoh, “Fully time-division multiplexed 100 Gbits/s optical transmission experiment,” Electron. Lett. 29, 2211–2212 (1993).
[CrossRef]

Tomlinson, W. J.

Uchiyama, K.

S. Kawanishi, H. Takara, K. Uchiyama, M. Saruwatari, T. Kitoh, “Fully time-division multiplexed 100 Gbits/s optical transmission experiment,” Electron. Lett. 29, 2211–2212 (1993).
[CrossRef]

Walge, E.

Wang, Q. Z.

Q. D. Liu, J. T. Chen, Q. Z. Wang, P. P. Ho, R. R. Alfano, “Single-pulse degenerate-cross-phase modulation in a single-mode optical fiber,” Opt. Lett. 20, 542–544 (1995).
[CrossRef] [PubMed]

Q. Z. Wang, Q. D. Liu, E. Walge, P. P. Ho, R. R. Alfano, “High resolution spectra of cross-phase-modulation in fibers,” Opt. Lett. 19, 1636–1638 (1994).
[CrossRef] [PubMed]

P. P. Ho, Q. Z. Wang, Q. D. Liu, Disa Liu, R. R. Alfano, “High resolution spectra of cross-phase-modulation for an A/D Converter,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. SPIE2155, 37–40 (1994).
[CrossRef]

Weiner, A. M.

Yang, G.

Yen, R.

Appl. Opt. (2)

Electron. Lett. (4)

S. Kawanishi, H. Takara, K. Uchiyama, M. Saruwatari, T. Kitoh, “Fully time-division multiplexed 100 Gbits/s optical transmission experiment,” Electron. Lett. 29, 2211–2212 (1993).
[CrossRef]

M. E. Marhic, C. H. Hsia, J.-M. Jeong, “Optical amplification in a nonlinear fiber interferometer,” Electron. Lett. 27, 210–211 (1991).
[CrossRef]

T. Morioka, K. Mori, M. Saruwatari, “Ultrafast polarization independent optical de-multiplexer using optical carrier frequency shift through cross-phase-modulation,” Electron. Lett. 28, 1070–1072 (1992).
[CrossRef]

Y. Kimura, K. I. Kitayama, N. Shibata, S. Seikai, “All-fiber-optic logic and gate,” Electron. Lett. 22, 277–278 (1986).
[CrossRef]

J. Opt. Soc. Am. B (1)

Opt. Commun. (2)

J.-M. Jeong, M. E. Marhic, “All optical logic gate based on cross-phase-modulation of a nonlinear fiber interferometer,” Opt. Commun. 85, 430–436 (1991).
[CrossRef]

J.-M. Jeong, M. E. Marhic, “All optical analog to digital and digital to analog conversion implemented by a nonlinear fiber interferometer,” Opt. Commun. 91, 115–122 (1992).
[CrossRef]

Opt. Lett. (8)

Phys. Rev. A (1)

R. H. Stolen, C. Lin, “Self-phase-modulation in silica optical fibers,” Phys. Rev. A 17, 1448–1453 (1978).
[CrossRef]

Phys. Rev. Lett. (1)

R. R. Alfano, S. L. Shapiro, “Observation of self-phase-modulation and small scale filaments in crystals and glasses,” Phys. Rev. Lett. 24, 592–594 (1970).
[CrossRef]

Other (2)

P. P. Ho, Q. Z. Wang, Q. D. Liu, Disa Liu, R. R. Alfano, “High resolution spectra of cross-phase-modulation for an A/D Converter,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. SPIE2155, 37–40 (1994).
[CrossRef]

R. R. Alfano, The Supercontinuum Laser Source (Springer-Verlag, New York, 1989).
[CrossRef]

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Figures (6)

Fig. 1
Fig. 1

Design of a 16-level XPM spectral encoding method.

Fig. 2
Fig. 2

TDM unary encoding 16-level design: one channel (16 × 1) and four Channels (4 × 4) fiber/pulse sequence approaches.

Fig. 3
Fig. 3

Experimental arrangement of 5 Gsamples/s, 16-level XPM digitization unit. A 30-ps mode-locked Nd:YAG laser system was used to produce 1064-nm pulses and 532-nm second-harmonic generation pulses at a 10-Hz repetition rate. The energy of the pump (1064-nm pulses, signal to be digitized) was adjusted with neutral-density filters in the 1–100-nJ range, and the energy of the probe (532-nm pulses, carrier) was <1 nJ. For single-pulse digitization, only one XPM fiber was used. The waveguide splitter and combiner were removed. Fiber/waveguide splitter and combiner were used for a pulse sequence generator (PSG). For the optical pulse sampling (1064 nm) and clocking carrier pulse (532 nm) we used a 1 × 4 and 4 × 1 fiber–waveguide splitter and combiner. At the output of the combiner, each pulse was separated by ∼200 ps because of the consecutive fiber length difference of ΔL = 4 cm. These pulse-delayed TDM fibers after XPM fibers (single mode) were multimode fibers with a larger diameter to minimize unwanted nonlinear optical effects. XPM fibers are 1-m-long single mode for the XPM process of 532- and 1064-nm pulses. The wavelength demultiplexer was a 1-m Jarell–Ash spectrometer to disperse spectral-broadened 532-nm XPM pulses. We used a 600-lines/mm grating blazed at 1 µm. The 532-nm modulated signals were collected at the second order of the grating to double the spectral resolution. The unary encoder had variable length fiber bundles; see Fig. 4 for details. We used a streak camera with two-dimensional imaging and a 10-ps time resolution to validate the XPM-encoded TDM trains. The y axis of the image represents the camera input slit location from 16 encoded TDM fibers and the x axis represents the time sweep of the streak camera.

Fig. 4
Fig. 4

Schematic diagram of a 16-level (4-bit) TDM unary encoder. The broadened XPM spectrum was collected directly into this variably delayed fiber array for unary-encoded TDM trains. Multimode fibers were used to form four sets of a four-bundle encoder. ΔZ, the length difference between each adjacent fiber channel, was 1 cm (50-ps delay).

Fig. 5
Fig. 5

Photograph of the time-divided unary-encoded optical pulse digitization from XPM-broadened and shifted spectra measured by a streak camera. The input signal wavelength is 1064-nm, the carrier pulse wavelength is 532 nm. The photograph shows a single-pulse input signal with a relative analog intensity of 15. We observed 16 unary pulses from the streak camera output. One horizontal division equals 100 ps.

Fig. 6
Fig. 6

Photograph of a four-pulse train input signal with a relative input intensity of 9:10:11:18. The measured digitized unary output pulses were 10:11:12:16. Extra brightness from signal 18 was due to uneven splitting of the 532-nm carrier pulse in the 1 × 4 waveguide–fiber splitter. One horizontal division equals 200 ps.

Tables (1)

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Table 1 Encoded Bright Spots from Four Input Pulses

Equations (5)

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nw=n0w+n2wIw,
Δw2XPM2 w2zn2w1E1t2/c,
Iout=1=0 0 0 0, 0 0 0 0, 0 0 0 0, 0 0 0 1;  for 2>Ii1,Iout=2=0 0 0 0, 0 0 0 0, 0 0 0 0, 0 0 1 1;  for Ii15,Iout=16=1 1 1 1, 1 1 1 1, 1 1 1 1, 1 1 1 1.
w532I1064=w532+ΔwXPM=w532+KI1064=w532+NΩ,
on/off=Ibright-Ibackground/Idark-Ibackground>80/20=4.

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