Metal treatment – Stock – Amorphous – i.e. – glassy
Reexamination Certificate
2000-05-05
2003-09-30
Wyszomierski, George (Department: 1742)
Metal treatment
Stock
Amorphous, i.e., glassy
C385S137000
Reexamination Certificate
active
06627008
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to grooved substrates for positioning and retaining optical fibers to be used in optical communications, and more particularly to the grooved substrates for use in multifiber optical connectors which can realize coupling of the connectors by using guide pins or the grooved substrates for aligning the multiple optical fibers, which substrate is capable of positioning and retaining the optical fibers therein. This invention also relates to methods for the production thereof.
2. Description of the Prior Art
As an optical connector to be used for connecting the optical fibers to each other, heretofore, the fitting type optical connector as shown in
FIGS. 1 and 2
, for example, is known in the art. The multifiber optical connector
10
a
(in the example shown in the drawings, four-fiber optical connector) is basically composed of a V-grooved substrate
11
and a retaining substrate
14
fixed to the V-grooved substrate
11
through the medium of an adhesive. The V-grooved substrate
11
is provided with a plurality of V-grooves
12
for optical fibers formed therein parallel to each other, each groove having a cross-sectional contour of the letter V, and V-grooves
13
for guide pins formed on the opposite side of the V-grooves
12
. By joining the retaining substrate
14
to the V-grooved substrate
11
, the holes for optical fibers and those for guide pins are respectively formed by the V-grooves
12
for optical fibers and the V-grooves
13
for guide pins in the joining area thereof. The multifiber optical connector
10
a
is prepared by inserting and adhering the optical fibers
16
into the holes for optical fibers and polishing the end face of the assembled connector. Another multifiber optical connector
10
b
is similarly provided with a plurality of holes for optical fibers into which the optical fibers
16
are inserted and adhered, but has guide pins
15
projected at the positions aligned with the V-grooves
13
for guide pins mentioned above. The mutual coupling of the optical connectors
10
a
,
10
b
is performed by inserting the guide pins
15
into the holes for guide pins mentioned above. The reference numeral
17
denotes a fiber tape.
The V-grooved substrate for aligning multiple optical fibers is also used in a mechanical splice for abutting, the optical fibers against each other and joining them by fusion thereof or through the medium of an agent for adjusting the refractive index, to align and retain the optical fibers therein.
FIGS. 3 and 4
illustrate an example of the four-fiber mechanical splice. The mechanical splice
20
is composed of a V-grooved substrate
21
having V-grooves
22
formed therein for positioning the optical fibers
16
, a retaining substrate
25
, and a clamp spring
28
of the snap-in fitting type capable of exerting the holding power to clamp them. The V-grooved substrate
1
is provided with guide grooves
24
respectively formed at opposite ends of the parallel V-grooves
22
and wedge guide grooves
23
of a prescribed number (four, in the example shown in the drawing) at one longitudinal edge. Similarly, the retaining substrate
25
is provided with wedge guide grooves
26
formed therein at the position aligned with the wedge guide grooves
23
mentioned above. Each wedge insertion hole
27
is formed by a pair of upper and lower wedge guide grooves
23
and
26
. The attachment of the optical fibers
16
to the mechanical splice
20
is performed by inserting wedges
29
into the wedge insertion holes
27
mentioned above to form a gap between the substrates
21
and
25
, inserting the optical fibers
16
into the gap from opposite ends so as to abut the ends of the optical fibers against each other, and pulling the wedges
29
out of the holes
27
thereby allowing the upper and lower substrates
21
and
25
to be clamped with the clamp spring
28
and establishing the connection of the optical fibers.
As the materials for the V-grooved substrates, heretofore, a wafer of silicon single crystal as disclosed in published Japanese Patent Application, KOKAI (Early Publication) No. (hereinafter referred to briefly as “JP-A-”) 6-82656 and JP-A-5-134146, alumina, or a glass filler-containing epoxy :resin as disclosed in JP-A7-181338 is used. The V-grooves are formed by the anisotropic etching of silicon when the wafer of silicon single crystal is used as the substrate material or by the grinding process when alumina is used. In the case of an epoxy resin, the V-grooved substrate is manufactured by the injection molding.
SUMMARY OF THE INVENTION
In the manufacture of the V-grooved substrates for multifiber optical connectors, it is very important to minimize the clearance between the guide pin and the guide pin hole as possible, without mentioning that the positioning of the optical fiber holes to the guide pin holes and the mutual distance between the optical fiber holes should be adjusted in the submicron order.
When a wafer of silicon single crystal is used as a substrate material, the V-grooves are formed by the anisotropic etching of silicon as mentioned above. However, this processing is expensive. Further, the guide pin holes entail such problems as wear and micro-deformation thereof when the guide pins are frequently attached to and detached from the guide pin holes of the above substrate, which increases the clearance between the guide pin and the guide pin hole and eventually results in the deviation from the mutual alignment of the optical fibers. As a result, it will be difficult to connect the optical fibers stably with a low connector insertion loss.
When the substrate material is alumina, it takes a longer time for forming V-grooves. In addition thereto, since it needs the grinding process with high processing cost, the V-grooved substrate obtained will be inevitably expensive.
On the other hand, when the V-grooved substrate is manufactured from an epoxy resin, it can be produced by the injection molding at a low cost. It poses, however, a serious problem of the increase in the clearance between the guide pin and the guide pin hole with the repeated attachment and detachment of the guide pin to and from the hole, as in the case of the substrate made from the wafer of silicon single crystal.
As described above, heretofore, it is not possible to manufacture the grooved substrate that allows the multifiber optical connector to stably maintain the low connector insertion loss (no increase in the clearance between the guide pin and the guide pin hole) at a low cost from the conventional materials such as the wafer of silicon single crystal, alumina, and epoxy resins.
The grooved substrate for aligning multiple optical fibers is also required to possess the mechanical strength, wear resistance, and other properties because wedges are used to release the clamping action.
It is, therefore, an object of the present invention to provide an inexpensive grooved substrate which possesses a sufficient strength, incurs only sparingly such problems mentioned above as causing wear and micro-deformation by the repeated attachment and detachment of the guide pins or the wedges and allows an optical connector prepared by using this grooved substrate to maintain the stable low connector insertion loss.
A further object of the present invention is to provide a method which, owing to the combination of a technique based on the conventional metal mold casting process or molding process with the quality of an amorphous alloy exhibiting a glass transition region, allows a grooved substrate satisfying a predetermined shape, dimensional accuracy, and surface quality to be mass-produced with high efficiency by a simple process and, therefore, enables to omit or diminish markedly such machining steps as grinding and consequently provide an inexpensive grooved substrate excelling in durability, strength, resistance to impact, resistance to wear, elasticity, etc. expected of the grooved substrate.
To accomplish the object mentioned above, the first aspect of the presen
Arai Toshio
Nagahora Junichi
Taniguchi Takeshi
Wyszomierski George
YKK Corporation
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