Optical waveguides – With disengagable mechanical connector – Structure surrounding optical fiber-to-fiber connection
Reexamination Certificate
2001-01-24
2003-04-22
Nguyen, Khiem (Department: 2839)
Optical waveguides
With disengagable mechanical connector
Structure surrounding optical fiber-to-fiber connection
C385S076000, C385S139000, C439S534000
Reexamination Certificate
active
06550977
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an optical fiber connector and more specifically to an improved apparatus for connecting optical fibers in a pair of optical fiber connectors.
2. Description of the Related Art
In recent years, the widespread use of communication, such as “Internet”, leads to the abrupt increase of traffic in communication, which urges the introduction of WDM (Wavelength Divisional Multiplexing) system into the core network of the communication system. The WDM system can allows multiplexed optical signals to be carried in a single optical fiber for improve the efficiency of transmission. Accordingly, the intensity of the light transmitted by the optical fiber becomes lager, because the transmitted optical signals are multiplexed by the system.
Similar to the conventional network using the electrical conductive wires, the transmission lines using the optical fibers should be interconnected and branched at required portions in the network by optical fiber connectors and adapters. For these connections and branches of the lines, various kinds of optical fiber connectors for providing the suitable connections and branches of lines at required portions have been manufactured and used selectively.
With reference to
FIGS. 1
to
3
, a conventional optical fiber connectors mounted on a printed circuit board is described in detail.
FIG. 1
shows an optical fiber connector
3
which is one of the conventional optical fiber connectors known and standardized as SC type optical fiber connector. The optical fiber connector
3
can be connected with or disconnected from another optical fiber connector by the use of an adapter described hereinafter. An optical fiber cable
1
including an optical fiber (not shown) is protected from abrupt bending with a strain relief jacket
2
formed in cone-shape made of a flexible material such as rubber or similar one. Through the jacket
2
, the cable
1
is introduced into the optical fiber connector
3
.
The optical fiber connector
3
has, at a peripheral portion, an outer housing
4
which is of generally rectangular shape in a section along the line P—P in FIG.
1
and is made of synthetic resin. A knurled handle
5
is formed on the periphery of the housing
4
but around the housing
4
for easy operation when the optical fiber connector
3
is inserted into or released from the adapter. A marking
6
, near apart a polarizing tab or a key
7
as a projection, formed at a central portion of a wall of the housing
4
is provided as an indicator to notice whether the optical fiber connector
3
is inserted by sufficient depth into the adapter. The optical fiber in the optical fiber cable
1
is guided to an end face of a ferrule
8
via a bore or hole provided along an axis of the ferrule
8
.
With reference to
FIG. 2
, a connection between both optical fiber connectors
3
is explained. A pair of optical fiber connectors
3
is connected to be optically coupled with each other by the mean of the adapter
15
. Each of parts having the same or similar function has reference of same numeral before hyphen such as
2
-
1
and
2
-
2
when it is necessary to distinguish one of parts having identical or similar function from the other. The adapter
15
has cavities suitable to receive the outer housings
4
of the optical fiber connectors and an aligning ferrule for aligning the ferrules
8
so that the front ends of the optical fibers can be faced each other.
Thus a pair of optical fiber connectors
3
-
1
and
3
-
2
are coupled via the adapter
15
. Both of the ferrules
8
-
1
and
8
-
2
, which are not shown in
FIG. 2
, are pushed each other by springs (not shown) mounted in each connectors
3
-
1
and
3
-
2
. Accordingly the front ends or the front faces of the ferrules
8
-
1
and
8
-
2
come close to each other, hence the optical fibers in each ferrules
8
-
1
and
8
-
2
are allowed to transmit optical signals to each other with little transmission loss.
These optical fiber connectors
3
-
1
and
3
-
2
coupled to the adapter
15
can be released from the adapter
15
, by the way that one of the connectors
3
-
1
,
3
-
2
is gripped at the knurled handle
5
and then pulled rearward the connector
3
-
1
or
3
-
2
from the adapter
15
, while the adapter
15
is being fixed by the other hand. The other connector
3
-
1
or
3
-
2
can also released in the same way.
As described above, the connection and the release of the optical fiber connectors
3
-
1
,
3
-
2
can be done easily by one touch handling.
With reference to
FIG. 3
, one of applications of a pair of the optical fiber connectors
3
-
1
,
3
-
2
mounted on a printed circuit board assembly
31
applied to an optical unit, such as WDM, is described. The printed circuit board assembly
31
includes a printed circuit board
32
, hereinafter referenced to simply as PCB, having the connectors
3
-
1
,
3
-
2
, electronic parts, and others. The printed circuit board assemblies
31
are slidably inserted into a rack (not shown) of the unit along the guide grooves (not shown) mating with an upper and lower ends of the PCBs
32
, maintaining its surface being generally vertically. At the front end portion of the PCB
32
is provided a front panel
35
, at a rear end portion of the PCB
32
are provided connectors for electrical connection with connectors mounted to the unit. The electrical connection can be accomplished by plug-in way at the same time when the printed circuit board assembly
31
is sufficiently inserted into the rack.
The front panel
35
having an uniformly wide flange upstanding to the sheet is provided at the front portion of the PCB
32
, hence the front portion is covered from upper to lower against the exterior of the rack. The front panel
35
, further includes required parts for indicating or operating the unit.
The adapter
15
is mounted on a portion near the front panel
35
on the PCB
32
via a figure-L-shaped angle
36
with bolts or rivets. A portion of the adapter
15
is exposed forward from the flange of front panel
35
through an opening thereof. The optical fiber connector
3
-
1
,
3
-
2
are inserted obliquely downward and upward into the adapter
15
respectively for transmitting or receiving optical signals between both connectors
3
-
1
,
3
-
2
.
When the PCB assembly
31
shown in
FIG. 3
is used for transmitting optical signals in the optical unit, the other end of the optical fiber
1
-
1
of the optical fiber connector
3
-
1
is coupled with an optical transmitter-module including a semiconductor laser (not shown in FIG.
3
), hence a laser light is transmitted to the front face of the ferrule
8
within the inner connector
3
-
1
.
During the optical module being active as described above, the outer connector
3
-
2
should be released from the optical adapter
15
prior to tests for measuring operating characteristics of the optical signal, or condition of transmission line connected with the connector
3
-
2
. And then an optical fiber connector connected to a test unit may be inserted to the adapter
15
, and after the test the outer connector
3
-
2
should be again connected to the adapter
15
. In this situation, these connections to the adapter
15
may be done in watching the opening of the adapter
15
to make sure the position of the adapter
15
.
It should be avoided to see the adapter
15
in facing the opening of the adapter
15
, because the laser light transmitted out of the optical fiber may impinge directly on eye resulting in an injury, while it is safe to see obliquely the adapter
15
and the opening of the adapter
15
is designed so as to look downwards as possible. However the increase of power of the optical signals is liable to cause the damage.
To avoid this dangerous matter, therefore, the opening of the adapter
15
is faced as obliquely downwardly as possible. However, with consideration of increase of the amount of power transmitted in an optical fiber cable, it is desired that an assembly of optical fiber connectors may minimize the occurre
Nguyen Khiem
Staas & Halsey , LLP
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