Abrading – Abrading process – Glass or stone abrading
Reexamination Certificate
2002-07-31
2004-12-07
Wilson, Lee D. (Department: 3723)
Abrading
Abrading process
Glass or stone abrading
C451S028000
Reexamination Certificate
active
06827632
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to methods for manufacturing and polishing fiber optic components. More particularly, the present invention relates to methods for polishing fiber optic attenuator ferrules.
BACKGROUND OF THE INVENTION
Fiber optic attenuators are optical components that induce a calibrated loss between two connectors to dampen (i.e., attenuate) an optical signal. Attenuation is desirable if the optical signal has a power level that exceeds the operating range of the equipment to which the signal is being transferred. Excessive signal power can cause saturation at the receiver and induce system errors and failures. Attenuation is typically achieved by passing the signal through an absorption filter or an air gap. Conventional fiber optic attenuators are available in bulkhead, in-line and build-out configurations.
FIGS. 1 and 2
illustrate a prior art in-line attenuator
20
. The attenuator
20
includes a ferrule assembly
22
mounted within a housing
24
. The ferrule assembly
22
includes a ferrule structure
26
having a first end face
28
accessible from a first end
29
of the housing
24
, and a second end face
30
accessible from a second end
31
of the housing
24
. The ferrule assembly
22
also includes a hub
32
located at a mid-region of the ferrule structure
26
. The hub
32
nests within a hub receiver
33
defined by the housing
24
. An attenuating structure (e.g., an absorption filter or air gap) is located within the ferrule structure
26
.
FIG. 3
shows the attenuator
20
providing an optical coupling between first and second fiber optic connectors
40
and
50
. In
FIG. 3
, a cover
61
(shown in
FIG. 1
) at the first end
29
of the housing
24
has been pivoted open to expose the first end face
28
. The first connector
40
is inserted over the first end
29
of the housing
24
, and the second connector
50
is inserted within the second end
31
of the housing
24
. The first connector
40
includes a ferrule
42
having an end face
43
that abuts against the end face
28
of the ferrule structure
26
when the connector
40
is coupled to the attenuator housing
24
. The second connector
50
includes a ferrule
52
having an end face
53
that abuts against the end face
30
of the ferrule structure
26
when the connector
50
is coupled to the attenuator housing
24
. In use, optical signals are transferred between the connectors
40
,
50
by passing through the ferrule assembly
22
. As the signals pass through the ferrule assembly
22
, the desired attenuation is provided.
To improve performance parameters such as insertion loss and return loss, it is desirable to polish the end faces
28
,
30
of the ferrule structure
26
. It is preferred for the end faces
28
,
30
to be polished at a slight angle (e.g., about 8 degrees relative to a plane perpendicular to a longitudinal axis of the ferrule). To ensure acceptable performance levels, it is preferred for the angled end faces
28
,
30
of the ferrule/hub assembly
22
to abut angled end faces
43
,
53
of the connector ferrules
42
,
52
in a generally parallel relationship as shown in FIG.
3
. Slight deviations in the relative orientations of the end faces can result in air gaps between the end faces
28
,
43
and
30
,
53
(see
FIG. 4
where misalignment is shown between the end faces
28
and
43
). This type of misalignment can be detrimental to the optical performance of the coupling.
In the prior art, the end faces
28
and
30
of the ferrule structure
26
are typically polished prior to mounting the ferrule assembly
22
in the housing
24
. One reason for this practice is because the end face
30
of the ferrule structure
26
is not accessible for polishing once the ferrule structure
26
has been mounted within the attenuator housing
24
. However, it has been determined that when the ferrule assembly
22
is mounted within the housing
24
after the end faces
28
,
30
have already been polished, part tolerances mismatches can cause the end faces
28
,
30
to be slightly rotationally offset from their intended rotational orientations. With the end faces
28
,
30
rotationally offset from their intended orientations, the end faces
28
,
30
may not make parallel contact with the connector end faces
43
,
53
when the connectors
40
,
50
are coupled to the attenuator
20
. As indicated above, this type of misalignment can be detrimental to the optical performance of the coupling.
SUMMARY
The present disclosure relates to methods for ensuring the proper rotational alignment of a ferrule within a housing. It will be appreciated that the specific method steps disclosed herein are examples of one way the broad concepts of the present invention may be put into practice, and that variations can be made with respect to the described method steps without departing from the broad scope of the inventive concept.
REFERENCES:
patent: 4649670 (1987-03-01), Snyder
patent: 5018316 (1991-05-01), Mulholland et al.
patent: 5480344 (1996-01-01), Xu et al.
patent: 5813081 (1998-09-01), Wang et al.
patent: 5883995 (1999-03-01), Lu
patent: 5947797 (1999-09-01), Buzzetti
patent: 5984531 (1999-11-01), Lu
patent: 6076973 (2000-06-01), Lu
patent: 6183343 (2001-02-01), Buzzetti
patent: 6190239 (2001-02-01), Buzzetti
patent: 6220763 (2001-04-01), Stephenson
patent: 6296398 (2001-10-01), Lu
patent: 6461055 (2002-10-01), Zimmel
patent: 6547653 (2003-04-01), Yamada et al.
“Fiber Optic. Cable Assemblies and Accessories,”ADC Telecommunications, Inc., pp. 1-23 (Apr. 2003).
“LX.5® Small-Factor-Connector,”ADC Telecommunications, Inc., pp. 2-3 (Sep. 2001).
Pomroy William J.
Zimmel Steven C.
ADC Telecommunications Inc.
Merchant & Gould P.C.
Wilson Lee D.
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