Optical waveguides – With disengagable mechanical connector – Optical fiber to a nonfiber optical device connector
Reexamination Certificate
2001-05-23
2003-05-20
Sanghavi, Hemang (Department: 2874)
Optical waveguides
With disengagable mechanical connector
Optical fiber to a nonfiber optical device connector
C385S137000, C385S136000, C385S091000
Reexamination Certificate
active
06565266
ABSTRACT:
CLAIM OF PRIORITY
This application claims priority to an application entitled “Device for Aligning Optical Source and Optical Fiber in Optical Source Module” filed with the Korean Industrial Property Office on Aug. 1, 2000 and there duly assigned Ser. No. 2000-44531.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an optical source module and, in particular, to a device for aligning an optical source and an optical fiber in the optical source module.
2. Description of the Related Art
In general, the function of an optical source module is essential in all aspects of transmitting and receiving an optical signal in an optical communications system. Namely, an optical source module is typically used as a pump laser diode module, semiconductor optical-amplifier module, and for transmitting/receiving module in the range of 155 Mbit and 2.5 Gbit.
FIG. 1
a
is a top view illustrating the construction of a conventional optical source module.
FIG. 1
b
is a side view illustrating the construction of the conventional optical source module. As shown in
FIGS. 1
a
and
1
b
, the conventional optical source module
100
comprises a housing
110
, a substrate
120
, a laser diode
130
, a photo diode
140
, an optical fiber
150
, an optical ferrule
160
, a saddle
170
, a thermoelectric cooler
180
, a thermister
190
, and, a window ferrule
162
.
According to the conventional optical source module
100
with the above construction, the laser diode
130
and an optical fiber
150
are aligned according to the following steps. First, the laser diode
130
is mounted on the substrate
120
. Then, the optical fiber
150
and the optical ferrule
160
are soldered together, and the lower portion of the saddle
170
is mounted on the substrate
120
. Thereafter, when electric power is supplied to the laser diode
130
to emit light, the position of the optical ferrule
160
is adjusted to realize a maximum light-receiving position. Once the maximum light-receiving position is determined, the saddle
170
and the optical ferrule
160
are welded together. Here, the thermal distortion caused by this welding process should be within an alignment allowable error range.
In order to obtain a higher optical coupling efficiency between the optical fiber and the laser diode, a lens having the same shape as archenterons of the laser diode is processed at one end of the optical fiber for a precise alignment in six axes. Here, the error range of an axis should be within the least allowable error range, which is preferably less than 0.2 &mgr;m.
FIG. 2
a
is a side view illustrating a device for aligning an optical source and an optical fiber according to a first embodiment of the conventional art.
FIG. 2
b
is a front view of the device in
FIG. 2
a
.
FIG. 3
is a side view magnifying an optical ferrule and saddles of the device in
FIG. 2
a
.
FIG. 4
is a side view magnifying an optical ferrule and saddles of the device in accordance with a second embodiment of the conventional art.
Referring to
FIGS. 2
a
to
4
, the saddles
170
and
270
of the device for aligning the optical source and the optical fiber according to the first and second embodiments of the conventional art are thermally distorted to a degree of 5 to 20 &mgr;m in an y-axis (vertical) direction due to the heat applied to the respective welded sections S. Once the heat is applied to the welded sections S, the heat is conducted toward the arrow direction, as shown in
FIGS. 3 and 4
. Also, as the optical ferrule
160
including the optical fiber
150
is displaced downward in a vertical direction, the vertically-downward displacement of the optical ferrule
160
decreases optical coupling efficiency between the optical source and the optical fiber, thereby impeding reliability of the optical source module.
FIG. 5
a
is the side view of a device for aligning an optical source and an optical fiber according to a third embodiment of the conventional art.
FIG. 5
b
is a view illustrating the cross section line B-B′ in
FIG. 5
a
.
FIG. 6
a
is a side view of the device for aligning an optical source and an optical fiber according to a forth embodiment of the conventional art.
FIG. 6
b
is a view illustrating the cross section line A-A′ in
FIG. 6
a
.
FIG. 7
is a graph illustrating the thermal distortion of the device according to the third and forth embodiments of the conventional art. Here, the horizontal axis represents time, while the vertical axis represents the degree of thermal distortion, respectively.
Referring to
FIGS. 5
a
to
6
b
, the saddles
370
and
470
of the device according to the third and forth embodiments of the conventional art includes arms
372
and
473
formed with distance from bases
371
and
471
, respectively. In this prior art system, the saddles
370
and
470
exhibit a relatively small value of 0.4 &mgr;m in thermal distortion in the y-axis direction as shown in FIG.
7
.
However, the degree of thermal distortion is greater than the allowable error range, which should be less than 0.2 &mgr;m for thermal distortion in the vertical direction for optimal performance. In order to obtain an optimal error range, the optical ferrule
160
is frequently removed using a gripper to re-align the optical ferrule
160
, and such an operation is a time-consuming process and cumbersome during the manufacturing process. Moreover, a residual stress which occurs during the fabrication process should be minimized to enhance the durability of the optical source module. Thus, it is apparent that a need exists for improved techniques for packaging optical modules, such that internal fiber connections can be utilized without increased manufacturing cost, decreased reliability and other problems associated with a conventional optical source module.
SUMMARY OF THE INVENTION
The present invention is directed to a device for aligning an optical source and an optical fiber in an optical source module to minimize a thermal distortion and residual stress caused by the welding of the optical fiber ferrule and the saddle member.
The present invention is related to a device for aligning an optical source and an optical fiber in an optical source module to maintain a higher optical coupling efficiency without re-alignment after the first alignment attempt between the optical source and the optical fiber.
Accordingly, the present invention provides a device capable of aligning an optical source and an optical fiber in an optical source module, which includes a substrate for mounting the optical source, an optical fiber ferrule for supporting the optical fiber so that the optical fiber can receive light emitted from the optical source, and a saddle mounted on the substrate near the optical source for supporting the optical fiber ferrule. The saddle includes a pair of base layers spaced a part by a predetermined distance; a sub-rib member near extending upwardly from the inner end, adjacent to the optical fiber ferrule, of the respective base layer; a center-rib member having a smaller width than the sub-rib layer extending upwardly from the center portion of the respective sub-rib layer; an arm member having a greater width than the center rib extending upwardly from the top of the respective center-rib member, the respective arm member having a pair of welded area positioned at both ends for coupling the optical fiber ferrule along a longitudinal direction of the optical fiber ferrule; a reinforcing member having tapered ends extending upwardly from the top portion of the respective arm member; and, a loop member for coupling the top end of the respective reinforcing member together.
REFERENCES:
patent: 6190056 (2001-02-01), Kwon et al.
patent: 2002/0025126 (2002-02-01), Finot et al.
Kang Dae-Hyun
Kwon Oh-Dal
Mun Gi-Tae
Park Ki-Soo
Yang Young-Soo
Cha & Reiter
Rojas Omar
Samsung Electronics Co,. Ltd.
Sanghavi Hemang
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