Optical waveguides – With disengagable mechanical connector – Optical fiber/optical fiber cable termination structure
Reexamination Certificate
2000-04-21
2001-05-22
Sikder, Mohammad Y. (Department: 2872)
Optical waveguides
With disengagable mechanical connector
Optical fiber/optical fiber cable termination structure
C385S079000, C385S080000, C385S081000
Reexamination Certificate
active
06234684
ABSTRACT:
TECHNICAL FIELD
The present invention is related to an optical connector in which an optical fiber projects from a connection end surface of a ferrule, a method of setting a projection length of the optical fiber of the optical connector, and a fixture for setting the projection length of the optical fiber.
BACKGROUND ART
An optical connector is in use in which an optical fiber projects a little longer from a connection end surface of an optical connector. In this type of optical connector, it is necessary to set a projection length the optical fiber projects from the connection end surface to a constant length. A fixture for and a method of assembling such an optical connector are proposed in Japanese Laid-Open Patent Publication No. Sho-64-77003.
However, what is proposed in the publication requires that a support seat which has a complex structure is used for a ferrule, an optical fiber cored line, etc., and that a projection length of an optical fiber from an end surface of the ferrule is set using a microscope. Hence, a structure of a required apparatus is complicated, a manner in which the apparatus is to be handled is complex, and it is not possible to efficiently assemble an optical connector in the field where optical connectors are connected to each other.
Further, with respect to a conventional optical connector, a sufficient study has not been yet given to a relationship between a projection length of an optical fiber and a connection characteristic of connection of optical fibers through connectors. While the technique described in the publication above discloses to set a projection length of an optical fiber to 50 &mgr;m as a guideline, there is a doubt if the disclosed projection length is appropriate.
The present invention has been made to solve such a theme. Accordingly, an object of the present invention is to obtain an optical connector in which a projection length an optical fiber projects from a tip (i.e., connection end surface) of a ferrule is set to an optimal value, and a method of and a fixture for easily setting the projection length of the optical fiber of the optical connector in the field where optical connectors are connected to each other.
DISCLOSURE OF THE INVENTION
The present invention uses the following means to achieve the object above. That is, in the invention directed to an optical connector in which a ferrule includes an optical fiber insertion hole which opens in a connection end surface of the ferrule and an optical fiber which is inserted through the optical fiber insertion hole is fixedly held by the ferrule, means for solving the problem is a structure in which the optical fiber which is inserted through the optical fiber insertion hole projects 10 to 30 &mgr;m from the connection end surface of the ferrule.
Meanwhile, in the invention directed to a method of setting a projection length of an optical fiber of an optical connector, means for solving the problem is a structure in which a recess surface is formed locally in a ferrule receiving surface, against which a connection end surface of a ferrule of the optical connector is pressed, to a depth which is equal to a projection length the optical fiber is to project from the connection end surface of the ferrule, with the connection end surface of the ferrule pressed against the ferrule receiving surface across the recess surface, the optical fiber which is inserted through an optical fiber insertion hole is then projected from the connection end surface of the ferrule while pressed against the recess surface, and with the optical fiber pressed against the recess surface, the optical fiber is fixed to the ferrule.
In the invention directed to a fixture for setting a projection length of an optical fiber of an optical connector, means for solving the problem is a structure which comprises: a ferrule receiving surface whose local portion includes a recess surface which is formed to a depth which is equal to a projection length the optical fiber is to project from a connection end surface of a ferrule of the optical connector; ferrule holding means for holding the ferrule for free movement against the ferrule receiving surface in such a manner that an opening formation region for an optical fiber insertion hole which is opened in the connection end surface of the ferrule is opposed against the recess surface of the ferrule receiving surface; ferrule pressing means for pressing the ferrule which is held by the ferrule holding means against the ferrule receiving surface; cored line holding part for holding an optical fiber cored line with a tip of the optical fiber inserted into the optical fiber insertion hole of the ferrule, said cored line holding part being free movable in a direction of the ferrule receiving surface; and cored line pressing means for pressing said cored line holding part toward the ferrule receiving surface so that the tip of the optical fiber which projects from the optical fiber insertion hole is pressed against the recess surface of the ferrule receiving surface.
According to the present invention, the connection end surface of the ferrule is pressed against and across the recess surface which is formed in the ferrule receiving surface, the optical fiber which is inserted through the optical fiber insertion hole of the ferrule is pressed against the recess surface of the ferrule receiving surface, and in this condition, the optical fiber is fixedly held by the ferrule so that the optical fiber projects an optimal length which is the same as the depth of the recess surface from the connection end surface, whereby a desired optical connector is easily assembled.
Since the optical connector according to the present invention requires that the optical fiber projects a projection length of 10 to 30 &mgr;m from the connection end surface of the ferrule, a desirable connection characteristic is obtained which satisfies both a connection loss and a reflection attenuation due to connection of optical connectors. Hence, it is possible to obtain an optical connector which exhibits an excellent connection characteristic of connection using connectors and which is highly reliable.
Further, with respect to setting of the projection length the optical fiber projects from the connection end surface of the ferrule, it is possible to accurately set the projection length of the optical fiber which is equal to the depth of the recess surface in an extremely easy manner, only by pressing the tip of the optical fiber which penetrates the ferrule against the recess surface while pressing the ferrule against the ferrule receiving surface. It is therefore possible to easily set the projection length of the optical fiber in the field where optical connectors are connected to each other, without requiring skill of an operator. Thus, the present invention is remarkably valuable.
In addition, the fixture for setting a projection length of an optical fiber of an optical connector according to the present invention is extremely easy to handle, since the fixture has a simple structure which comprises the ferrule receiving surface which includes the recess surface whose depth is equal to a projection length the optical fiber is to project, means for holding the ferrule and abutting the connection end surface of the ferrule against the ferrule receiving surface, and means for pressing the tip of the optical fiber which penetrates the ferrule against the recess surface of the ferrule receiving surface. Moreover, it is possible to accurately set the projection length of the optical fiber, and therefore, it is possible to provide such a fixture for setting a projection length of an optical fiber according to the present invention which has such an excellent capability at an inexpensive price.
REFERENCES:
patent: 4729624 (1988-03-01), Kakii et al.
patent: 4892378 (1990-01-01), Zajac et al.
patent: 4911518 (1990-03-01), Miller
patent: 4994134 (1991-02-01), Knecht et al.
patent: 5131063 (1992-07-01), Monroe et al.
patent: 5390270 (1995-02-01), Hanazawa et al.
patent: 5815618 (1998-09-01), Takahashi
Furukawa Shin-ichi
Hayashi Takehiro
Hogari Kazuo
Kanai Ken
Kawamura Yasumoto
Greene Kevin E.
Lacasse Randy W.
Lacasse & Associates
Sikd-er Mohammad Y.
The Furukawa Electric Co. Ltd.
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