Optical waveguides – With disengagable mechanical connector – Optical fiber/optical fiber cable termination structure
Reexamination Certificate
2002-07-18
2004-11-23
Duverne, J. F. (Department: 2839)
Optical waveguides
With disengagable mechanical connector
Optical fiber/optical fiber cable termination structure
Reexamination Certificate
active
06821025
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to fiber-optic cleaning systems and, more specifically, to cleaning systems for cleaning fiber-optic endfaces.
BACKGROUND OF THE INVENTION
The proliferation of fiber-optic communications has led to its widespread implementation and use in industry, especially in the fields of telecommunications and data communications. It is well known in the industry that fiber-optic endfaces must be kept clean and undamaged within fiber-optic communication systems. A fiber-optic endface is the cross-sectional surface that is created when an optical fiber is cut for termination. The fiber-optic endfaces are typically supported by a connector that couples to a bulkhead adapter (also sometimes referred to as a backplane adapter or a mating adapter) having an alignment sleeve for receiving the fiber-optic endface.
Failure to keep an endface clean and undamaged results in signal loss because of scattering effects at the endface of the optical fiber. As bandwidths increase, particularly with the rise of wavelength division multiplexing (WDM) technology, the need for cleanliness at the fiber-optic endface is even more important. Further, since fiber-optic communication systems handle heavy bandwidth traffic, the cleanliness at the fiber-optic endface is particularly important because the laser power driving the fiber-optic communication signals is typically higher. When a high-powered laser strikes a small piece of debris on the fiber-optic endface, the debris bums, leaving a film of soot on the fiber-optic endface that degrades communication signals. As a result, the “dirty” fiber-optic endface at the interconnect point must be taken out of service and repaired.
While cleanliness of the fibers is of utmost importance, access to the fiber endface is often very limited. Most fiber-optic interconnects are arranged in a male-to-male configuration and utilize a female-to-female configured alignment sleeve for coupling. Thus, when the user-side connector is removed, one endface is readily accessible, while the other resides at the bottom of a deep narrow hole. This makes cleaning very difficult. Further, backplane fiber-optic interconnects are notoriously difficult to access for maintenance, cleaning, and repair. Whether multi-fiber or single-fiber (simplex), these fiber-optic connectors are typically located near the back of a narrow “card slot”. A typical slot is 1.5 inches wide and 12 inches deep, and rather difficult to access for service. Most current cleaning techniques require the user to disassemble the backplane to gain access to the connector for cleaning.
To overcome the access problem, some cleaning system manufacturers have designed cleaning systems that are insertable within the alignment sleeve for cleaning the fiber-optic endfaces without necessitating the removal of the connector from the bulkhead adapter. However, the methods used by these systems are disadvantageous for several reasons. For instance, most of these methods utilize contact cleaning methods, wherein the endface is directly contacted by a non-fluid material, such as a cotton swab or a physical structure coated with an adhesive. Because the fiber-optic endface is directly contacted by a non-fluid material, these systems contain the inherent risk of adding contamination to the fiber-optic endface as a portion of the non-fluid contact material may remain on the fiber-optic endface. Further, the physical contact may result in the introduction of defects upon the fiber-optic endface, such as scratches on the fiber-optic endface through “brushing” of the media across the fiber-optic endface or the “dragging” of a contaminate particle across the endface. Thus, it is widely understood that contact cleaning methods are one of the leading causes of endface scratching, which often results in signal degradation.
Other cleaning manufacturers have designed cleaning systems that involve injecting a liquid within the bulkhead adapter for cleaning the fiber-optic endfaces without necessitating the removal of the connector from the backplane. However, current methods of this nature are also disadvantageous for several reasons. For instance, a typical bulkhead adapter is not watertight, therefore significant quantities of the liquid, such as water, are leaked from the bulkhead adapter, thereby presenting a potential or a perceived potential for damage to the expensive communication equipment located in proximity to the connector. Further, these systems do not provide an immediate evacuation system for the rapid removal of the liquid injected within the bulkhead adapter, thus increasing the potential for damage to the surrounding communications equipment and increasing the potential for residuals of the fluid to remain on the endface, thus contaminating the endface.
Moreover, it has been found that during cleaning operations, cleaning solvents may collect in a chamfer formed in the fiber-optic endface. The chamfer is located around the periphery of the fiber-optic endface. The chamfer acts as a protected cavity, which ultimately forms a reservoir that retains solvent within the alignment sleeve. Thus, after the cleaning process is complete, the cleaning solvent and any contaminants contained in the chamfer often flow back onto the fiber-optic endface, recontaminating the endface.
Further, existing assemblies do not incorporate an inspection microscope within the cleaning assembly or a means to receive one. Thus, the cycle time to clean and inspect a fiber-optic endface is increased since the operator is forced to swap between the cleaning assembly and an inspection microscope. Further still, the potential for the introduction of contaminants or damage to the fiber endface due to the repetitive coupling and decoupling of the cleaning assembly and inspection microscope during the cleaning process is also substantially increased. In other aspects, a manufacturer must design/develop separate tooling to produce and inventory two separate units, a cleaning assembly and a microscope, resulting in increased costs relative to a combined unit.
Therefore, a need exists for a cleaning assembly that is effective in cleaning fiber-optic endfaces while exhibiting a reduced potential of contamination introduction and/or damage to the fiber-optic endface being cleaned and does not expose nearby components to rogue fluids. Further, there exists a need for a cleaning assembly that is operable to receive or contains a microscope therewithin to reduce the cleaning process cycle time and risk of fiber-optic endface contamination.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the present invention, a cleaning apparatus for cleaning an endface of an optical fiber contained within an interface device is provided. The cleaning apparatus includes a housing having an interface portion adapted to be received by the interface device and a first nozzle at least partially disposed within the housing. The first nozzle is operable to deliver a pressurized gas and a solvent upon the endface of the optical fiber when the interface portion of the housing is received by the interface device to aid in the removal of contaminants on the endface.
In accordance with further aspects of the invention, the cleaning apparatus further includes an evacuation passageway through the housing for removing the pressurized gas and the solvent released from the first nozzle. Preferably, the solvent is a liquid comprised of a hydrocarbon and a terpene mixture. In accordance with still further yet aspects of the invention, the cleaning apparatus may also include a second nozzle disposed at least partially within the housing and operable to dispense the pressurized gas.
In accordance with other aspects of the present invention, the cleaning apparatus further includes a microscope-receiving aperture, wherein the microscope-receiving aperture is operable to selectively receive a microscope for inspecting the endface of the optical fiber. Hence, the cleaning apparatus may also include a microscope attached to the housing v
Christensen O'Connor Johnson & Kindness PLLC
Duverne J. F.
Westover Scientific, Inc.
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