Optical waveguides – With optical coupler – Plural
Reexamination Certificate
1998-10-14
2001-09-18
Font, Frank G. (Department: 2877)
Optical waveguides
With optical coupler
Plural
Reexamination Certificate
active
06292602
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical signal transmission system and an optical signal transmission device using the system. More particularly, it relates to an optical signal transmission system using single mode optical fibers (SMF) as transmission paths to realize advantageous optical signal transmissions at super high speed, and an optical signal transmission device using the system.
2. Description of the Related Art
No optical transmission system has achieved 10 Gb/s optical signal transmission or greater at super high speed using single mode optical fibers as transmission paths until now.
Especially, although experimental results of generating a sub-signal, determining normality of repeaters, and switching optical transmission paths needed for an optical transmission system have been reported, no system for practical use has been reported.
When the conventional system is employed for generating a sub-signal, determining normality of repeaters, and switching optical transmission paths, the following structure may be formed, for example:
In other words, it is assumed that a sub-signal is accumulated by electrically modulating a main signal. Alternatively, the different optical source from the main signal is used to realize a method for generating a sub-signal determining normality of repeaters, and switching optical transmission paths.
For electrical modulation of a main signal, however, there is a need for devising a frame structure of the main signal. Especially, when a 10 Gb/s main signal or greater is employed, modulation causes much technical troubles relative to super high speed operations in an electrical circuit. Alternatively, this causes problems, such that a circuit scale becomes larger, and further, the cost becomes larger when different optical sources are employed respectively for main and sub-signals.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an optical signal transmission system to generate a sub-signal without employing an exclusive optical source, determining normality of repeaters, and switching for sub-signal transmission when a failure occurs, and an optical transmitter using the system.
The above-described problems are attained by 1. an optical signal transmission system, including first and second optical signal transmission devices connected each other through an optical transmission path, the first optical signal transmission device generating phase conjugation lights having first and second optical wavelengths, which are different each other, according to a main signal light having a first optical wavelength and an exciting light of a second optical wavelength, modulating intensity of the phase conjugation light of the second optical wavelength by a sub-signal, of which speed is lower than that of the main signal light, and concurrently transmitting the first phase conjugation light and the second phase conjugation light, of which intensity is modulated by the sub-signal, through the optical transmission path.
Additionally, the second optical signal transmission device demultiplexing in wavelength division the first phase conjugation light transmitted through the optical transmission path and the second phase conjugation light intensively modulated by the sub-signal, respectively to receive the main and sub-signals.
Alternatively, in other preferred mode, the first optical signal transmission device generates phase conjugation lights having first and second optical wavelengths, which are different each other, according to a main signal light of a first optical wavelength and an exciting light of a second optical wavelength, modulates intensity of the main signal light of the first optical wavelength by a sub-signal of which speed is lower than that of the main signal light, and concurrently transmits the first phase conjugation light and the main signal light, of which intensity is modulated by the sub-signal, through the optical transmission path.
Furthermore, in the other mode, the first optical signal transmission device generates plural phase conjugation lights, employs one of the plural phase conjugation lights to transmit a main signal light, modulates intensities of the phase conjugation lights, which are different from the one phase conjugation light for transmitting the main signal, with a sub-signal, of which speed is lower than that of the main signal light, and concurrently transmits the optical signal, of which intensity is modulated, with the phase conjugation light for transmitting the main signal light.
It becomes possible that wavelength of the phase conjugation light and excision light except that of the above-described phase conjugation light for transmitting the main signal are employed for identifying plural repeating amplifiers arranged on the optical transmission path to enable determination of a failed point.
Alternatively, the above-described sub-signal can be employed as switch information of working and protection groups.
Further, other objects of the present invention will become clear by the description for explaining embodiment according to the attached drawings.
REFERENCES:
patent: 5430568 (1995-07-01), Little et al.
patent: 5532868 (1996-07-01), Gnauck et al.
patent: 6026204 (2000-02-01), Chbat
patent: 7-98464 (1995-04-01), None
patent: 7-301830 (1995-11-01), None
patent: 8-171102 (1996-07-01), None
patent: 9-203914 (1997-08-01), None
Font Frank G.
Fujitsu Limited
Natividad Phil
Staas & Halsey , LLP
LandOfFree
Optical signal transmission system and optical signal... 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 signal transmission system and optical signal..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical signal transmission system and optical signal... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2450753