Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
1998-03-11
2001-04-17
Bovernick, Rodney (Department: 2874)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S049000, C385S078000, C385S089000, C385S014000
Reexamination Certificate
active
06217231
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical fiber assembly, an optical module including an optical fiber assembly, and a manufacturing process thereof.
With wide spreading use of optical telecommunication in human society, there is an increasing impetus to deploy optical subscriber systems including optical home terminals.
FIG. 1
shows the construction of a typical optical home terminal
10
.
Referring to
FIG. 1
, the optical home terminal
10
includes a housing
11
in which a circuit assembly
12
is accommodated. The circuit assembly
12
includes a printed circuit board
13
carrying thereon various electronic components
14
and an optical fiber assembly
15
. In order to reduce the cost of the optical home terminal
10
, it is desired to mount the optical fiber assembly
15
and the electronic components
14
on the printed circuit board
13
by a solder reflowing process. Further, it is desired to reduce the cost of the optical fiber assembly as much as possible.
FIG. 2
shows the construction of a conventional optical fiber assembly
20
.
Referring to
FIG. 2
, the optical fiber assembly
20
includes a housing
21
accommodating therein an optical device
22
. The housing
21
includes a through-hole
25
, and a ferrule
24
provided at an end of an optical fiber
23
is fitted into the through-hole
25
. Further, a lens
26
is disposed between the foregoing end of the optical fiber
23
and the optical device
22
in the housing
21
. Thereby, an optical fiber cable
27
extends outside the housing
21
.
In operation, the optical beam emitted by the optical device
22
is injected into the optical fiber
23
after being focused by the lens
26
. Further, the optical beam exited from the foregoing optical fiber end is focused upon the optical device
22
by way of the lens
26
.
FIGS. 3A and 3B
show another conventional optical fiber assembly
30
.
Referring to
FIGS. 3A and 3B
, the optical fiber assembly
30
includes a housing
31
in which a block
32
, a ferrule
33
and a split sleeve
34
are accommodated, wherein the block
32
includes a V-shaped groove
32
a
and a flat top surface
32
b
for carrying an optical device
35
. The ferrule
33
holds therein an optical fiber
36
such that a free end part of a bare optical fiber extends from the ferrule
33
. Thereby, the bare optical fiber
36
thus extending from the ferrule
33
is held by the V-shaped groove
32
a
such that the end of the optical fiber
36
faces the optical device
35
within an error of ±1 &mgr;m. As noted already, the ferrule
33
is held by the split sleeve
34
.
Further, a ferrule
37
of an optical connector is inserted into the housing
31
for a fitting engagement with the split sleeve
34
.
In the construction of
FIG. 2
, there is a drawback in that the optical fiber assembly
20
cannot be mounted on a printed circuit board by a solder reflowing process because of the existence of the optical fiber cable
27
extending from the optical fiber assembly
20
. Thus, it has been necessary to mount the optical fiber assembly
20
manually on the printed circuit board, while such a manual mounting process increases the cost of the optical home terminal. In addition, the optical fiber assembly
20
, using the lens
26
therein, has a complex structure and the assembling process thereof is difficult. In other words, the construction of the optical fiber assembly
20
itself is disadvantageous for reducing the cost of the optical home terminal.
On the other hand, the optical fiber assembly
30
of
FIGS. 3A and 3B
, lacking the optical fiber cable extending therefrom in the outward direction, can be mounted on a printed circuit board successfully by using a solder reflowing process. On the other hand, the optical fiber assembly
30
has a drawback in the point that the bare optical fiber
36
having a diameter of only 125 &mgr;m may be damaged when assembling the optical fiber assembly
30
. Thus, the yield of the optical fiber assembly
30
is tend to be deteriorated and the cost of the optical home terminal is increased.
While it is possible to construct such that the ferrule
33
engages the V-shaped groove
32
a
, such a construction cannot provide the necessary accuracy of positioning the optical fiber in view of the fact that the ferrule
33
has a diameter of 1-2.5 mm and cannot be positioned precisely within the error of ±1 &mgr;m by engaging with the V-shaped groove
32
a
. Further, it is difficult to form the V-shaped groove
32
a
with a size of 1 mm or more for accepting the ferrule
33
while still maintaining the foregoing precision of ±1 &mgr;m.
SUMMARY OF THE INVENTION
Accordingly, it is a general object of the present invention to provide a novel and useful optical fiber assembly and a manufacturing process thereof wherein the foregoing problems are eliminated.
Another and more specific object of the present invention is to provide an optical fiber assembly in which the necessary optical alignment between an optical fiber and an optical device is achieved easily and efficiently with high precision.
Another object of the present invention is to provide an optical module including an optical fiber assembly in which the optical module can be mounted on an external printed circuit board by way of a solder reflowing process.
Another object of the present invention is to provide an optical fiber assembly, comprising:
a substrate having a principal surface;
an optical device provided on said substrate;
a ferrule carrying an optical fiber, said ferrule being defined by a circumferential surface;
said ferrule including a cutout part on said circumferential surface, said cutout part including a flat cutout surface formed on said circumferential surface so as to extend in an axial direction of said ferrule;
said substrate being mounted on said flat cutout surface such that said principal surface engages said flat cutout surface.
Another object of the present invention is to provide an optical fiber assembly, comprising:
a substrate defined by first and second, mutually opposing principal surfaces;
an optical device provided on said substrate; and
a ferrule having an end surface and carrying therein an optical fiber, said ferrule having a cut-in part on said end surface, said cut-in part being defined by a pair of mutually parallel surfaces and a rear surface exposing an end surface of said optical fiber;
said substrate being inserted into said cut-in part such that said first and second principal surfaces of said substrate engage said parallel surfaces of said cut-in part respectively, said optical device and said exposed end surface of said optical fiber being aligned optically.
Another object of the present invention is to provide an optical fiber assembly, comprising:
a ferrule carrying an optical fiber, said ferrule having a circumferential surface;
a cutout part provided on said circumferential surface of said ferrule, said cutout part being defined by a flat cutout surface and a cutout end surface, said cutout end surface exposing an end surface of said optical fiber; and
an optical device provided on said flat cutout surface in optical alignment with said exposed end surface of said optical fiber.
According to the present invention, it is possible to achieve an optical alignment between the optical device on the substrate and the optical fiber held by the ferrule by providing the cutout part to the ferrule. As the optical fiber is protected by the ferrule, the risk that the optical fiber is damaged by the process of optical engagement is minimized. By engaging the principal surface of the substrate and the cutout surface of the ferrule, the optical alignment of the optical device and the optical fiber held in the ferrule is achieved easily and efficiently with high precision. Alternatively, the optical device may be provided directly on such a cutout surface of the ferrule.
Another object of the present invention is to provide an optical module, comprising:
a housing including a first region and a second region;
an optica
Mesaki Akitoshi
Yamane Takashi
Bovernick Rodney
Fujitsu Limited
Kang Juliana K.
Staas & Halsey , LLP
LandOfFree
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