Structures for optical semiconductor module, optical connector, and shape adapting optical connector

An optical semiconductor module structure comprises a housing which has an optical coupling means comprising an optical semiconductor element and a ferrule accommodating an optical fiber therein, a portion of said housing for holding said ferrule being formed to be a protuberant portion, wherein said optical semiconductor module structure is provided with, for coupling an optical connector with said protuberant portion, a means for regulating said optical connector in the direction of the axis of said ferrule and a means for regulating said optical connector in a direction right to the axis of said ferrule.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a coupling structure of an optical 
connector, in particular, to that of an optical connector serving as an 
optical connecting device to be connected to a small-sized optical 
component which is, like an optical semiconductor module used in an 
optical communication system and others, fixed to a board. 
2. Description of Prior Art 
There have been developed and used various types of optical connectors and 
some of them are disclosed in Japanese Patent Provisional Publications No. 
211276 of 1997, No. 43453 of 1997, and No. 265026 of 1997. Among them, in 
an embodiment where an optical semiconductor module disclosed in Japanese 
Patent Provisional Publication No. 211276 of 1997 and an optical 
connecting device using the optical semiconductor module are employed, the 
embodiment has an optical semiconductor module, which has a package body 
accommodating a semiconductor laser and an optical fiber optically coupled 
thereto and double side walls respectively provided with a recess and 
formed in the traveling way of the laser light radiated from the 
semiconductor laser, and a simplified connector to be coupled with said 
module, having a recess in the inner wall holding a ferrule to which one 
end of the optical fiber is fixed, and being provided at its front end 
with a protuberance, and optical fibers are optically coupled with each 
other through the coupling of the ferrules by coupling the simplified 
connector with the optical semiconductor module. 
Though these conventional optical connectors are suitable, to some extent, 
for producing a large amount of low cost and small-sized optical 
semiconductor modules indispensable in optical fiber communication 
systems, they usually still have some following problems. That is to say, 
special tools are necessary for centering the ferrules during the assembly 
work of coupling the module with the connector, and this makes the 
assembly difficult. In case that the coupling sequence for a mate optical 
semiconductor module starts from a ferrule and there is no means to ensure 
the centering for the ferrules, a successful coupling is hard, the ferrule 
or a sleeve is sometimes damaged, and the coupling work eventually becomes 
difficult. Further, even if there is a guide means for centering the 
ferrules, this guide means does not sufficiently answer the need of low 
cost because the guide means is provided as a member completely 
independent of a lock means for locking the coupling of the mate optical 
semiconductor module, and this causes an increase in the number of 
components. Furthermore, the optical connection has been unstable due to 
the lack of means for ensuring the ferrule alignment after the coupling. 
An object of the present invention is to provide a structure allowing the 
conventional technological problems described above to be eliminated for 
an optical semiconductor module, an optical connector, or a shape adapting 
optical connector. 
SUMMARY OF THE INVENTION 
According to an aspect of the present invention, there is provided an 
optical semiconductor module structure provided with a housing which has 
an optical coupling means comprising an optical semiconductor element and 
a ferrule accommodating an optical fiber therein, a portion of said 
housing for holding said ferrule being formed to be a protuberant portion, 
wherein said optical semiconductor module structure is provided with, for 
coupling an optical connector with said protuberant portion, a means for 
regulating said optical connector in the direction of the axis of said 
ferrule and a means for regulating said optical connector in a direction 
right to the axis of said ferrule. 
According to another aspect of the present invention, there is provided, an 
optical semiconductor module structure provided with a housing which has 
an optical coupling means comprising an optical semiconductor element and 
a ferrule accommodating an optical fiber therein, a portion of said 
housing for holding said ferrule being formed to be a protuberant portion, 
wherein said optical semiconductor module structure is provided with, for 
coupling an optical connector with said protuberant portion, a means for 
guiding said optical connector and also locking the coupling of said 
optical connector. 
According to an embodiment of the present invention, the housing of the 
optical semiconductor module structure may have a means for regulating the 
direction of an optical connector to be inserted. 
According to another embodiment of the present invention, the housing of 
the optical semiconductor module structure may be provided with a means 
for regulating a plurality of directions of an optical connector to be 
inserted. 
According to still another embodiment of the present invention, the ferrule 
in the optical semiconductor module structure may be coupled via a split 
sleeve with an optical connector. 
According to still another aspect of the present invention, there is 
provided an optical connector structure, comprising a housing having a 
ferrule holding portion for holding a ferrule connected to an optical 
fiber, an elastic arm provided to said housing for retaining an optical 
coupling means, a means provided to said elastic arm for regulating said 
optical coupling means in the direction of the axis of said ferrule, and a 
means provided to said elastic arm for regulating said optical coupling 
means in a direction right to the axis of said ferrule. 
According to still another aspect of the present invention, there is 
provided a shape adapting optical connector structure, comprising a 
housing having a ferrule holding portion for holding a ferrule connected 
to an optical fiber, an elastic arm provided to said housing for retaining 
an optical coupling means, a means provided to said elastic arm for 
regulating said optical coupling means in the direction of the axis of 
said ferrule, and a means provided to said elastic arm for regulating said 
optical coupling means in a direction right to the axis of said ferrule, 
wherein said structure allows an optical coupling between 
differently-shaped optical coupling means. 
Referring to the attached drawings, an embodiment of the present invention 
will hereafter be described in details.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is a perspective and exploded view, illustrating an optical 
connector having a coupling structure as an embodiment of the present 
invention and an optical semiconductor module with which this optical 
connector is coupled. An optical connector 100, as shown in FIG. 1, 
comprises a housing 110 mainly made of such as plastic, a ferrule 120 for 
an optical fiber of an optical cable 1 to be connected, and a split sleeve 
150 for aligning the ferrules with each other. On the other, an optical 
semiconductor module 200 comprises a housing 210 mainly made of such as 
plastic, and a ferrule 220 which is held by the housing 210 and is aligned 
with a light emitting source (not shown), like a semiconductor laser, 
disposed inside the housing 210. In the illustrated embodiment, the 
optical semiconductor module 200 is mounted on a printed circuit board 
(PCB)(not shown) and has a plurality of connecting terminals 230 
surface-mounted on a conductor on the PCB. 
FIG. 2 is a sectional view of the housing 110 of the optical connector 100, 
and the structure of the housing 110 will be detailed with the reference 
to FIG. 1 and FIG. 2. The housing 110 has at its rear part a holding 
portion 111 formed to be easily held by two fingers (for example, a thumb 
and an index finger) and this holding portion 111 has at its middle part a 
hollowed space 112 for accommodating a ferrule assembly comprising the 
ferrule 120, a flange portion 130, and a deflection spring 140 (hereafter 
referred to as a ferrule assembly accommodating space 112). The central 
part of the rear end of the ferrule assembly accommodating space 112 is 
provided with an opening 112A through which the optical cable 1 is allowed 
to extend out. The housing 110 has at its virtually middle part a through 
passage 113, which is formed to communicate with the ferrule assembly 
accommodating space 112 and whose inner diameter is large enough to hold 
the front end part of the ferrule 120 and the rear end part of a split 
sleeve 150 (hereafter referred to as a ferrule holding through passage 
113). For this ferrule holding through passage 113, the housing has a pair 
of elastic arms 114 for guiding and locking the mate connector (hereafter 
referred to as guide/lock elastic arm 114) on the side of and the outer 
side of the mate connector, for example, the optical semiconductor module 
200. 
As clearly shown in FIG. 1, the guide/lock elastic arm 114, formed as a 
cantilever allowed elastically to open a little outward, is integrated 
with the body of the housing 110. This guide/lock elastic arm 114 has on 
the inner wall of its front end part a lock protuberance 114A for locking 
the coupled optical semiconductor module 200 as the mate connector. The 
lock protuberance 114A has guide grooves 114B, 114C formed in a cross as a 
whole for guiding and locating the ferrule 220 of the optical 
semiconductor module 200 as the mating connector. As described in later, 
these guide grooves 114B, 114C guide and locate the mate connector 
regarding its vertical and lateral directions respectively in FIG. 1, and 
therefore eventually fulfill as a whole the role of guiding and locating 
the mate connector in the dual axial directions. The guide pattern of 
these grooves according to the present invention is not limited to a 
cross, and the grooves may be structured in various patterns so that they 
work as plural axes guides for guiding and locating the mate connector in 
plural directions. Such guide patterns as T-shape, Y-shape, etc. may be 
allowable. 
The detailed structure of the housing 210 of the optical semiconductor 
module 200 will hereafter be described with the reference of FIG. 2 
illustrating a perspective view thereof clearly. The housing 210 has, on 
both sides 211A of its coupling portion 211, protuberant ridges 211B, 211C 
engaging respectively with the guide grooves 114B, 114C provided to the 
lock protuberance 114A arranged on the inner wall of the front end part of 
the guide/lock elastic arm 114 of the housing 110 of the optical connector 
100. 
How to operate and activate overall the optical connector 100 and the 
optical semiconductor module 200 constituted and structured as described 
above will hereafter be described. First, to couple the optical connector 
100 with the optical semiconductor module 200, an operator holds the 
holding portion 111 of the rear part of the housing 110 of the optical 
connector 100, for example, with his thumb and index finger and push the 
optical connector 100 into the optical semiconductor module 200 so that 
the guide grooves 114B of the guide/lock elastic arms 114 on both sides of 
the front portion of the housing 110 engage with the protuberant stripes 
provided to both sides 211A of the coupling portion 211 of the housing 210 
of the optical semiconductor module 200. During this process, the 
guide/lock elastic arm 114 is elastically deflected a little outward due 
to the effect of a cam face at the front end of the lock protuberance 114A 
which is pushed outward by the protuberant stripe 211C on the housing 210 
of the optical semiconductor module 200, and the front half of the lock 
protuberances 114A is allowed to ride over the protuberant ridge 211C, and 
at the moment when the ride-over has finished, i.e., the guide groove 114C 
has engaged with the protuberant ridge 211C, the elastic force of 
deflecting the guide/lock elastic arm 114 returns the guide/lock elastic 
arm 114 to its original closing position. At the same moment, due to the 
precise guide and location of the optical semiconductor module 
accomplished by the engagement between the guide groove 114B and the 
protuberant ridge 211B, the front portion of the split sleeve 150 provided 
to the ferrule 120 of the optical connector module 100 is correctly 
coupled with the front portion of the ferrule 220 of the optical 
semiconductor module 200. When the guide/lock elastic arm 114 has been 
closed, the guide grooves 114B, 114C engage with the protuberant ridges 
211B, 211C respectively and the ferrules 120, 220 are correctly aligned 
each other, and the optical connector 100 and the optical semiconductor 
module 200 couple with and lock up each other. FIG. 4 is a sectional view 
illustrating how the optical connector 100 and the optical semiconductor 
module 200 which couple with and lock up each other. 
In the embodiment above, a type of mate connector to be coupled with an 
optical connector is described as a type of optical semiconductor module 
placed on a printed circuit board, but the present invention, not being 
limited to such type of mate connector, may be applied to such type of 
mate connector to be connected to an optical cable. In the embodiment 
above, the optical connector has on its housing side a guide/lock elastic 
arm and the optical semiconductor module as the mate connector has on its 
housing side a protuberant stripe engaging with the guide/lock elastic 
arm, but the roles of the optical connector and the mate connector for the 
lock mechanism are interchangeable and therefore the present invention, 
not being limited to the embodiment above, for example, may be applied to 
such a case that a mate connector and an optical connector have on their 
housing sides a similar guide/lock elastic arm and a similar protuberant 
ridge engaging with the guide/lock elastic arm respectively. 
FIG. 5 is a perspective view of a constitution of a shape adapting 
connector of the present invention and an optical semiconductor module. 
FIGS. 6A, 6B, 6C are respectively front, side, and plan views illustrating 
how the shape adapting connector and the optical semiconductor module 
shown in FIG. 5 are coupled with each other. FIG. 7 is a perspective view 
of another constitution of a shape adapting connector of the present 
invention and an optical semiconductor module, and FIGS. 8A, 8B, 8C are 
respectively front, side, and plan views illustrating how the shape 
adapting connector and the optical semiconductor module shown in FIG. 7 
are coupled with each other. FIG. 9 is a perspective view of another 
constitution of a shape adapting connector of the present invention and an 
optical semiconductor module, and FIGS. 10A, 10B, 10C are respectively 
front, side, and plan views illustrating the shape adapting connector 
shown in FIG. 9. FIGS. 5 to 10 show embodiments of an adapter to which the 
present invention is applied for an optical semiconductor module and a MU 
connector specified in JIS. 
As shown in these FIGS., the adapter 300 has at its center a split sleeve 
350 held by a housing 311, a coupling portion on the side of the MU 
connector, coupling portions 314, 315 to be coupled with an optical 
semiconductor module 200, and a protuberance 330 fixed to board (or 
threaded protuberance fixed to side wall) provided to the bottom of the 
adapter 300. The coupling portion 314 is a guide/lock elastic arm of the 
present invention, and the coupling portion 315 is an auxiliary guide. 
When the optical semiconductor module 200 is coupled with the adapter, a 
ferrule 220 protruding out of the module 200 is inserted into the split 
sleeve 350. On the opposite side, when the adapter 300 is coupled with the 
MU connector, a ferrule of the MU connector is inserted into the split 
sleeve 350 and thereby the ferrule on the module side and the MU connector 
are coupled with each other by a constant force due to a spring in the MU 
connector. 
The present invention, without being limited to the embodiments described 
above, is applicable to other connectors including a SC connector 
specified in JIS. Especially in the embodiment of FIG. 5, a coupling 
portion 211 is structured to have only a protuberant ridge 211C for 
locking an elastic arm 314 of an optical connector. An elastic arm 314 is 
formed to have a groove 314C corresponding to the protuberant ridge 211C. 
In this embodiment, the guide of an optical connector is regulated by 
coupling an auxiliary guide 315 of an adapter 300 with an auxiliary guide 
recess 215 formed on the coupling portion 211. 
Especially in an embodiment of FIG. 7, a coupling portion 211 is provided 
with a protuberant ridge 211B and a protuberant ridge 211C which are 
disposed in a T-shape. An elastic arm 314 is formed to have grooves 314B, 
314C corresponding to the protuberant ridges 211B, 211C respectively. An 
embodiment constituted in this way, as shown in FIG. 1, can do without an 
auxiliary guide recess 215 formed on the coupling portion 211 and an 
auxiliary guide 315 of an adapter 300. 
Especially in an embodiment of FIG. 9, a coupling portion 211 is provided 
with a protuberant ridge 211B and a protuberant ridge 211C which are 
disposed in a L-shape. An elastic arm 314 is formed to have grooves 314B, 
314C corresponding to the protuberant ridges 211B, 211C respectively. An 
embodiment constituted in this way, as shown in FIG. 1 and FIG. 7, can do 
without an auxiliary guide recess 215 formed on the coupling portion 211 
and an auxiliary guide 315 of an adapter 300. 
Since the present invention allows a guide/lock elastic arm to serve as a 
member for guiding a mate connector to be correctly coupled with and for 
locking the coupling, the operability during the coupling has been 
improved without increasing the number of components. 
Since plural axes guides formed at a guide/lock elastic arm for guiding and 
locating in plural directions work to restrict the alignment of the 
ferrules after the coupling in plural directions including vertical and 
longitudinal directions, that is, in the directions of plural axes, the 
coupling and alignment can be kept more stabilized. 
Since the above embodiments of the present invention cause no increase in 
the number of components, they provide more inexpensive structures for an 
optical semiconductor module, an optical connector and a shape adapting 
optical connector.