Optical fiber connector

Details Optical fiber connector Optical fiber connector

2003-03-28

2004-12-28

Nguyen, Khiem (Department: 2839)

Optical waveguides

With disengagable mechanical connector

Reexamination Certificate

active

06835001

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefits of priority from the prior Japanese Patent Application No. 2002-91672, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical fiber connector including optical fibers.
2. Description of the Related Art
FIG. 5
is a sectional view illustrating how an optical fiber connector
51
is connected to an optical component
61
. The optical fiber connector
51
has a connector ferrule
53
and optical fibers
52
fixed in the connector ferrule. Guide pins
58
of the optical fiber connector
51
are inserted into respective guide holes (not shown) of the optical component
61
, whereby the optical fiber connector
51
is connected to the optical component
61
.
FIG. 6
is a longitudinal sectional view of the elements appearing in FIG.
5
. As illustrated, each optical fiber
52
is fixed in the connector ferrule
53
of the optical fiber connector
51
, and typically comprises two silica glass layers with different refractive indices, that is, a core
55
and a cladding
56
surrounding the core
55
.
Typically, the dimensions of single-mode fibers commonly used are as follows: The core
55
has a diameter of 5 to 10 &mgr;m, and the cladding
56
has an outer diameter of about 125 &mgr;m.
On the connection end face, of the optical fiber connector
51
, each optical fiber
52
protrudes from an end face of the connector ferrule
53
by about several micrometers.
On the other hand, the optical component
61
comprises, for example, an optical waveguide chip
69
. Typically, the optical waveguide chip
69
has a structure wherein a cladding
66
corresponding to the claddings
56
of the optical fibers
52
is formed on a substrate
67
of silicon or the like and cores
65
corresponding to the respective cores
55
of the optical fibers
52
are embedded in the cladding
66
. Each core
65
has a size of approximately 5 to 10 &mgr;m in width as well as in height, and the cladding
66
has a height of about 50 &mgr;m, for example.
As an exemplary part constituting the optical component
61
, a top plate
68
of epoxy resin or the like is affixed to the optical waveguide chip
69
including the substrate
67
, cores
65
and cladding
66
so that the optical component
61
may be connected to the optical fiber connector
51
.
FIG. 7
is a sectional view exemplifying a state in which the optical fiber connector
51
is connected to the optical component
61
. In the illustrated example, the optical component
61
has a connection end face
61
a
which is flat as a whole inclusive of the end faces of the substrate
67
, cladding
66
and cores
65
of the optical waveguide chip and the end face of the top plate
68
. Accordingly, the connection end faces
52
a
of the optical fibers
52
protruding from the connector ferrule in the optical fiber connector
51
can be brought into perfect connection, that is, desirable PC (Physical Contact), with the respective cores
65
of the optical waveguide chip
69
.
FIG. 8
is a sectional view illustrating another example of connection between the optical fiber connector
51
and the optical component
61
. In the example shown in
FIG. 8
, the optical component
61
has an uneven connection end face
61
b
, that is, the cores
65
and the cladding
66
are set back from the substrate
67
and the top plate
68
. Such unevenness of the connection end face
61
b
is often caused during polishing of the end face of the optical component
61
due to difference in abrasion resistance among the layers constituting the optical component, or is caused in high-temperature environments due to difference in the coefficient of thermal expansion among the layers. Thus, in some cases, the cores
65
are set back from the substrate
67
or the top plate
68
by about 0.5 &mgr;m, for example.
In such cases, the optical fibers
52
of the optical fiber connector
51
are obstructed by the most prominent part of the optical component
61
, for example, the top plate
68
in the example of
FIG. 8
, and the cores
55
thereof fail to come into PC with the respective cores
65
of the optical waveguide chip
69
, giving rise to a problem of, for example, increased connector insertion loss.
To solve the problem, a method may be employed in which the total thickness of the core
65
and cladding
66
of the optical waveguide chip
69
is made significantly greater than the diameter of the optical fiber
52
so that the optical fibers
52
protruding from the connection end face of the optical fiber connector
51
may not touch the substrate
67
or top plate
68
of the optical waveguide chip
69
. However, this method is not preferred in view of costs and time required to manufacture the optical waveguide chips
69
.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an optical fiber connector which permits the cores of optical fibers thereof to be connected to an optical component without fail even in cases where the connection end face of the optical component, to which the optical fiber connector is connected, is uneven and a region thereof to which the optical fibers are connected is recessed.
To achieve the object, the present invention provides an optical fiber connector comprising a connector ferrule having an end face serving as a connection end face side of the optical fiber connector, and an optical fiber fixed in the connector ferrule and protruding from the end face of the connector ferrule, wherein a central portion of the optical fiber including a core thereof protrudes from a peripheral portion thereof.


REFERENCES:
patent: 4925266 (1990-05-01), Huebscher et al.
patent: 6331081 (2001-12-01), Ohtsuka et al.
patent: 6398423 (2002-06-01), Novacoski et al.

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