Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
2000-01-12
2001-10-23
Ngo, Hung N. (Department: 2874)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S024000
Reexamination Certificate
active
06305851
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Field of the Invention
The present invention relates generally to optical fiber systems and, more particularly, to systems and methods that detect an imperfect connection of fibers of an optical pump.
B. Description of Related Art
Optical communication systems have replaced other communication mediums due to their many advantages. For example, optical communication systems typically have wide bandwidth and low attenuation, are immune to electrical noise, offer relatively secure transmission of signals, and can transmit signals over long distances.
Despite the low attenuation of optical communication systems, the optical signals they transmit nevertheless require amplification. Although many types of optical amplifiers currently exist, the most widely used amplifier includes an optical fiber doped with an optically active material, such as erbium or other rare earth elements. Generally, the core region of the optical fiber contains the dopant, which is optically excited to provide optical gain to an optical signal having a suitable wavelength. The dopant may be excited by subjecting it to an optical pump signal of a suitable pump wavelength. For example, an erbium-doped fiber amplifier amplifies optical signals of wavelengths in the range of 1520 nm to 1580 nm when pumped by an optical pump signal of wavelength 980 nm or 1480 nm.
Conventional systems typically use optical pump lasers to generate the pump signal. The lasers generate optical pump signals of high power density in the pump fibers and the connectors. Imperfect connections, caused, for example, by imperfect mating of fibers or by surface contamination on the fiber ends, such as oils, dust, or dirt, can absorb some of the optical pump power and cause a hot spot, which could irreparably damage the connector. Once damaged, the connector must be replaced.
Accordingly, there exists a need for a system which detects an imperfect connection before damage occurs to the connector.
SUMMARY OF THE INVENTION
Systems and methods consistent with the present invention address this need by monitoring back reflection from the pump connector to detect an imperfect connection before damage can occur.
In accordance with the purpose of the invention as embodied and broadly described herein, a system, in one implementation consistent with the present invention, prevents damage to at least one component of a laser apparatus including a laser that emits a light signal of increasing power during power up. At least one connector is also provided that receives the light signal from the laser, and reflects at least a portion of the light signal when an imperfect connection exists. The system includes a detector and a monitoring circuit. The detector detects the reflected light signal from the connector; and the monitoring circuit receives the reflected light signal, determines an amount of power in the reflected light signal, calculates a ratio of the power of the light signal emitted by the laser to the power in the reflected light signal, compares the ratio to a predetermined threshold to determine whether the imperfect connection exists, and shuts down the laser when the imperfect connection exists.
In another implementation consistent with the present invention, a system detects an imperfect connection in a laser component. The system includes a laser, a connector, and a monitoring circuit. The laser emits a light signal; the connector transmits the light signal external to the laser component and reflects at least a portion of the light signal when an imperfect connection exists; and the monitoring circuit detects an amount of the reflected light signal and determines that the imperfect connection exists when the detected amount of the reflected light signal exceeds a predetermined amount.
In yet another implementation consistent with the present invention, an optical amplifier includes an active optical fiber and at least one laser component. The laser component provides power to the active optical fiber. The laser component includes a laser, a connector, and a monitoring circuit. The laser outputs a light signal. The connector transmits the light signal to the active optical fiber and reflects at least a portion of the light signal when an imperfect connection exists. The monitoring circuit determines whether the imperfect connection exists using the reflected light signal.
REFERENCES:
patent: 5463710 (1995-10-01), Filgas et al.
patent: 6028661 (2000-02-01), Minami et al.
patent: 6205266 (2001-03-01), Palen et al.
Cammarata Michael R.
Ciena Corporation
Ngo Hung N.
Soltz David L.
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