Optical waveguides – With optical coupler – Plural
Reexamination Certificate
1999-08-25
2001-07-03
Ngo, Hung N. (Department: 2874)
Optical waveguides
With optical coupler
Plural
C359S199200, C359S199200, C359S199200
Reexamination Certificate
active
06256432
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polarization-independent optical demultiplexer, more particularly to the demultiplexer generating a constant four-wave-mixing beam without regard to an input polarization state using a dispersion-shifted fiber that is a nonlinear material with high refractive index.
2. Description of the Conventional Art
To meet upcoming demands in high-capacity multimedia application area using a high-speed optical communication network, powerful networks, that is, networks as fast as terabit/sec are needed. Various technologies are used to implement high-capacity optical networks that manipulate time-division-multiplexed signals. The demultiplexers are active components and demultiplex multiplexed optical signals with respect to channels. The demultiplexer is one of the components that require largest bandwidths in communication systems. The detailed operations and implementations regarding conventional optical demultiplexers are illustrated in the following references.
REFERENCES
1. U.S. patent documents
U.S. Pat. No. 05,457,559, Oct. 10, 1995, Apparatus for extracting an optical clock and apparatus for demultiplexing a time-division multiplexed signal.
U.S. Pat. No. 05,357,359, Oct. 18, 1994, Optical polarization-independent optical time division multiplexer and demultiplexer with birefringence compensation.
U.S. Pat. No 05,646,759, Jul. 8, 1997, Fiber loop mirror for time division demultiplexing.
2. Other publications
IEEE Journal of Lightwave Technology, Vol. 15, No. 11, November 1997, pp. 2051-2058, P. O. Hedekvist, M. Karlsson, and P. A. Andrekson, “Fiber four-wave demultiplexing with inherent parametric amplification”.
IEEE Electronics Letters, Vol. 26, No. 14, July 1990, pp. 962-964, K. J. Blow, N. J. Doran, and B. P. Nelson, “Demonstration of the nonlinear fiber loop mirror as an ultrafast optical demultiplexer”.
IEEE Electronics Letters, Vol. 34, No. 8, April 1998, pp. 803-805, S. Diez, R. Ludwig, and H. G. Weber, “Optical switch for TDM and WDM/TDM system demonstrated in a 640 Gbits/s demultiplexing experiment”.
SUMMARY OF THE INVENTION
According to an aspect of this invention, the polarization-independent optical demultiplexer with four-wave-mixing includes input beams, a first optical amplifier, a second optical amplifier, a first band pass filter, a second band pass filter, a 3-dB optical fiber coupler, a dispersion-shifted fiber, and a third band pass filter. The input beams include a pump beam and a signal beam. The first optical amplifier and a second optical amplifier amplify the input beams. The first band pass filter and the second band pass filter remove noises from the amplified spontaneous emission. The 3-dB optical fiber coupler combines the output signals of the first and the second band pass filters and generates two optical signals. The dispersion-shifted fiber generates a constant four-wave-mixing beam without regard to an input polarization state because polarization state of the output signal of the 3-dB optical fiber coupler gets scrambled. The third band pass filter demultiplexes a four-wave-mixing beam generated by the dispersion-shifted fiber.
According to other aspect of the polarization-independent optical demultiplexer with four-wave-mixing comprises input beams, a first optical amplifier, a second optical amplifier, a first band pass filter, a second band pass filter, a wavelength division multiplexing (WDM) optical coupler, a dispersion-shifted fiber, a 3-dB optical fiber coupler, an optical circulator. The input beams include a pump beam and a signal beam. The first optical amplifier and the second optical amplifier amplify the input beams. The first band pass filter and the second band pass filter remove noises from the amplified spontaneous emission (ASE). The WDM optical coupler divides the output optical signals of said first band pass filter into a first optical signal and a second optical signal. The dispersion-shifted fiber generates a constant four-wave-mixing beam without regard to an input polarization state of the first optical signal from the WDM optical coupler. The 3-dB optical fiber coupler combines the four-wave-mixing beam generated by the dispersion-shifted fiber with the second optical signal of the WDM optical coupler and generates a first optical signal and a second optical signal. The optical circulator rotates the first optical signal of the 3-dB optical fiber coupler and the output optical signal of the second band pass filter and makes output.
REFERENCES:
patent: 5357359 (1994-10-01), Uchiyama et al.
patent: 5457559 (1995-10-01), Saito et al.
patent: 5646759 (1997-07-01), Lichtman et al.
patent: 6008915 (1999-12-01), Zyskind
patent: 6097535 (2000-08-01), Terahara
patent: 6151145 (2000-11-01), Sivastava et al.
Blow et al., “Demonstration Of The Nonlinear Fibre Loop Mirror As An Ultrafast All-Optical Demultiplexer,”IEEE Electronics Letters, 26(14):962-964, Jul. 1990.
Diez et al. “All-optical switch for TDM and WDM/TDM systems demonstrated in a 640Gbit/s demultiplexing experiment,”IEEE Electronics Letters, 34(8):803-805, Apr. 16, 1998.
Hedekvist et al., “Fiber Four-Wave Mixing Demultiplexing with Inherent Parametric Amplification,”Journal of Lightwave Technology, 15(11):2051-2058, Nov. 1997.
Ahn Joon-Tae
Jeon Min-Yong
Kim Kyoung-Hon
Lee Hak Kyu
Lim Dong Sung
Electronics and Telecommunications Research Institute
Ngo Hung N.
Seed IP Law Group PLLC
Tarleton E. Russell
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