Abrading – Abrading process – Glass or stone abrading
Reexamination Certificate
2000-07-07
2002-08-20
Rachuba, M. (Department: 3723)
Abrading
Abrading process
Glass or stone abrading
C451S054000, C451S044000
Reexamination Certificate
active
06435946
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the fabrication of optical devices for fiber optic communication systems, and, in particular, to a method for reducing plating sliver contamination caused by friction processes during fabrication of such optical devices.
2. Description of the Related Art
In fiber optic communication systems, it is often desirable to block a particular wavelength of light or to have a particular wavelength of light pass through a fiber optic cable. The blocking or passing through of particular wavelengths of light is accomplished using optical devices known as isolators and filters, respectively.
FIG. 1
shows a side view of a conventional optical device
100
that will function as either an isolator or a filter, depending on the selection of device components. Optical device
100
comprises a device body
102
mounted (e.g., welded) between a pair of lens retainers
104
to form a sub-assembly that is itself mounted (e.g., welded) between a pair of Z-sleeves
106
. Each Z-sleeve
106
retains and terminates an optical fiber
108
; each lens retainer
104
holds a lens; and device body
102
holds either an isolator or a filter that determines whether optical device
100
functions as an optical isolator or as an optical filter. Optical device
100
has four cavities: one between the end of each optical fiber
108
and the lens in the corresponding Z-sleeve
106
and one between each lens and the isolator/filter in the device body
102
. For the fiber optic cable to function properly, optical fibers
108
must be precisely aligned within optical device
100
and the cavities must be completely or at least substantially free of unwanted particles.
Lens retainers
104
and Z-sleeves
106
are typically metal components that are plated to protect them from contamination. For example, lens retainers
104
are typically plated with gold plating over nickel plating, while Z-sleeves
106
are typically nickel plated only. To achieve precise alignment and to prevent contamination from the ambient atmosphere, the plated lens retainers
104
and Z-sleeves
106
are subjected, during fabrication, to a friction process (e.g., lapping) to form a flat (i.e., co-planar) surface.
For example,
FIG. 2
shows a side view of a conventional lens retainer
104
for the optical device of FIG.
1
. According to the prior art, surfaces
202
and
204
, which will be mated (e.g., by welding) to corresponding surfaces on body
102
and Z-sleeve
106
of
FIG. 1
, respectively, are lapped—after plating, but prior to welding—to ensure that the mating surfaces are flat. Unfortunately, slivers (e.g., burrs) of the plating may be left on the surface of the lens retainers after lapping, and these slivers may end up as unwanted particles within the cavities of the optical device. Although most of the slivers can be removed manually, vibration test failure rates are typically greater than 9% due to particle contamination. Also, manually removing plating slivers from the lapped surfaces of lens retainers (and Z-sleeves) increases manufacturing time and cost.
SUMMARY OF THE INVENTION
The present invention is directed to a technique for reducing the occurrence of plating slivers caused by friction processes (e.g., lapping). The inventors have discovered that plating sliver formation is related to the angle of the plating to the lapping stone or wheel used during the lapping process. To prevent plating slivers from forming, components such as lens retainers and Z-sleeves are chamfered or radiused so that the plating forms an angle to the lapping stone of between about 30 degrees and 60 degrees at the edges of the parts. The present invention can reduce the vibration failure rate to less than about 5%. Also, manual inspection and sliver removal can be eliminated, thereby saving time and labor cost.
In one embodiment, the present invention is a method for reducing occurrence of slivers caused by a friction process during manufacture of a component for an optical device having one or more cavities, comprising the steps of (a) removing one or more edges of a surface of the component to form a non-right angle to the surface; and (b) then using a friction process to remove material from the surface to provide a flat surface, whereby the occurrence of slivers on the component resulting from the friction process is reduced as a result of having removed the one or more edges of the surface, thereby decreasing failure rate for the component due to presence of slivers in the one or more cavities of the optical device.
In other embodiments, the present invention is a component or an optical device comprising a component manufactured in accordance with the above method.
In yet another embodiment, the present invention is a component for an optical device having one or more cavities, the component adapted to be mounted within the optical device at a flat surface of the component, wherein the flat surface of the component comprises one or more removed edges that form a non-right angle to the surface in order to reduce occurrence of slivers on the component resulting from a friction process during manufacture of the component, thereby reducing failure rate for the component due to presence of slivers in the one or more cavities of the optical device.
In still another embodiment, the present invention is an optical device comprising the above component.
REFERENCES:
patent: 5855503 (1999-01-01), Csipkes et al.
patent: 5893723 (1999-04-01), Yamanaka
patent: 6238278 (2001-05-01), Haftmann
patent: 6240235 (2001-05-01), Uno et al.
patent: 6366726 (2002-04-01), Wach et al.
patent: 2001/0012429 (2001-08-01), Wach et al.
Cintron Orlando
Krepps Donna M.
Marabella Philip
Agere Systems Guardian Corp.
Mendelsohn Steve
Rachuba M.
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