Optical: systems and elements – Optical amplifier – Correction of deleterious effects
Reexamination Certificate
1999-01-27
2001-12-04
Hellner, Mark (Department: 3662)
Optical: systems and elements
Optical amplifier
Correction of deleterious effects
C359S341200, C359S199200
Reexamination Certificate
active
06327075
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical gain equalization unit, an optical gain equalization method, and an optical fiber transmission line, and more particularly to an optical gain equalization unit, an optical gain equalization method, and an optical fiber transmission line for use in an optical fiber transmission line having multiple lines over which multiplexed signal lights are sent.
A conventional optical wavelength multiplexing system have multiplexed optical signals from a plurality of optical signal sources for transmission through an optical fiber transmission line on which Erbium Doped Fiber Amplifiers (EDFA) are installed. At the receiving end, an optical demultiplexer demultiplexes multiplexed light signals into a plurality of channels and sends each to a light receiver.
Normally, gain equalization units are also installed on the optical fiber transmission line on which erbium doped fiber amplifiers are installed. On such a transmission line, one gain equalization unit equalizes the gains of signals over a range of transmission line where a plurality of erbium doped fiber amplifiers are installed; the gain equalization unit is installed so that the gain equalization of each relay range is optimized. This optimization technology is described in Technical Report of Electronic Data Communication, OSC95-35, pp. 13-19, July 1995.
However, an optical fiber transmission line available today includes at least two communication lines, one up line and one down line. And, erbium doped fiber amplifiers are installed on each transmission line at a predetermined interval. Therefore, it is difficult to install gain equalization units at different points on a transmission line. In addition, because of variations in parts and so forth, the number of gain equalizers required for one line may differ from that required by another. This means that, even when the number of required gain equalization units depends on the line, the loss of a predetermined range of the optical fiber transmission line must be equal among lines.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a gain equalization unit and a gain equalization method which equalize the gains of the lines at a time and make the level diagram of each line constant. The gain equalization unit according to the present invention is installed at a predetermined interval on an optical fiber transmission line having a plurality of lines, with gain equalizers on at least one line and loss generators on at least one line. The gain equalizers equalize the powers of channels of each line in a redetermined range of the optical fiber transmission line and equalize the gains of channels of each line. The loss generators make the loss of each line constant. The gain equalization method according to the present invention equalizes the gains of at least one line in a predetermined range of the optical fiber transmission line and makes the loss of at least one line constant. The optical fiber transmission line according to the present invention has a plurality of lines and has gain equalizers installed at a predetermined interval on at least one line and loss generators installed on at least one line. The present invention equalizes the gains of the lines at a time and make the level diagram equal.
REFERENCES:
patent: 5436760 (1995-07-01), Nakabayashi et al.
patent: 5923450 (1999-07-01), Dugan et al.
patent: 6034812 (2000-03-01), Naito
patent: 59-92639 (1984-05-01), None
patent: 59-127003 (1984-07-01), None
patent: H08-278523 (1996-10-01), None
patent: 9-244079 (1997-09-01), None
Zhou et al, “Power Management System Design Modelling of Optical Multi-Wavelength Transport Networks”, 1994, IEEE, pp. 1503-1507.*
“Technical Report of Electronic Data Communication”, OSC95-35, pp. 13-19, Jul. 1995.
J. Zhou, et al., “Power Measurement System Design Modelling of Optical Multi-Wavelength Networks” Proceedings of the Global Telecommunications Conference (Globecom), US NewY ork, IEEE, 1994, pp. 1503-1507.
E. Shehadeh, et al., “Gain-Equalized, Eight-Wavelength WDM Optical Add-Drop Multiplexer with an 8d-B Dynamic Range” IEEE Photonics Technology Letters, US, IEEE Inc. New York, vol. 7, No. 9, Sep. 1, 1995, p. 1075-1077.
Hellner Mark
NEC Corporation
Scully Scott Murphy & Presser
LandOfFree
Optical gain equalization unit, optical gain equalization... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical gain equalization unit, optical gain equalization..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical gain equalization unit, optical gain equalization... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2556227