Optical waveguides – With disengagable mechanical connector – Optical fiber/optical fiber cable termination structure
Reexamination Certificate
2001-08-09
2002-12-17
Sircus, Brian (Department: 2839)
Optical waveguides
With disengagable mechanical connector
Optical fiber/optical fiber cable termination structure
C439S372000
Reexamination Certificate
active
06494623
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to fiber optic (optoelectronic) communications, and more particularly to pluggable fiber optic transceivers utilized in fiber optic systems.
BACKGROUND OF THE INVENTION
Fiber optic transceivers facilitate bi-directional data transmissions between electronic devices (e.g., computer, input/output system, peripheral device, or switch) and optical data links in fiber optic (optoelectronic) systems. Each transceiver includes a photodetector for converting optically encoded data received from an optical data link to electrically encoded data readable by a host electronic device, and a laser diode for converting electrically encoded data signals from the host electronic device that are converted into optical signals and transmitted to the optical data link. Each transceiver is mounted onto a circuit card assembly of the host electronic device, and is therefore typically packaged such that it occupies as little circuit card surface area as possible.
Small Form-factor Pluggable (SFP) transceivers are one type of transceiver having standardized physical dimensions and performance characteristics that are defined in the “Cooperation Agreement for Small Form-Factor Pluggable Transceivers”, as executed on Sep. 14, 2000 (herein “the Cooperation Agreement”), which is incorporated herein in its entirety. The Cooperation Agreement is part of an SFP Transceiver multi-source agreement whose purpose is to establish internationally compatible sources of pluggable fiber optic transceivers in support of established standards for fiber optic systems. Specifically, the Cooperation Agreement sets forth transceiver package dimensions, cage and electrical connector specifications, host circuit board layouts, electrical interface specifications, and front panel bezel requirements that are followed by each party.
FIG. 1
is a simplified exploded perspective view depicting a transceiver assembly
100
that complies with the Cooperation Agreement. Transceiver assembly
100
includes a host circuit board
130
upon which is mounted a standard female electrical connector
140
, a pluggable transceiver
150
, a cage
160
, and an optional bezel
180
(shown in dashed lines) that is mounted over the front end of transceiver assembly
100
.
Pluggable transceiver
150
includes transceiver electronics that are mounted in an elongated transceiver housing
151
that is designed for “pluggable” insertion into cage
160
. Transceiver housing
151
includes an upper surface defining several vent holes, a lower surface including a boss
152
(shown in dashed lines), and a front surface defining pair of receptacles
153
for receiving standard optical connectors
190
(e.g., duplex LC, MT-RJ, or SC connectors). Mounted within housing
151
is a circuit board
154
for supporting the transceiver electronics, which process data signals from and supply data signals to a photodetector
155
and a laser diode
156
, respectively. A pair of ferrules
157
is mounted in receptacles for aligning standard optical connectors (not shown) with photodetector
155
and laser diode
156
. Extending from the back end of circuit board
154
is a male connector card
158
including contacts
159
that mate with corresponding contacts
144
of female connector
140
when cage
160
is mounted on host circuit board
130
and pluggable transceiver
150
is fully inserted into cage
160
.
Referring to the center of
FIG. 1
, cage
160
includes a first side wall
161
, a second side wall
162
, a top wall
163
, and a bottom wall
164
that collectively define a front opening
165
for receiving pluggable transceiver
150
. Cage
160
also includes a back wall
166
, which includes a leaf spring for biasing transceiver
150
toward opening
165
. Extending downward from side walls
161
and
162
and back wall
166
are feet
167
that are press fitted into holes
135
formed in host circuit board
130
. Note that holes
135
are plated with a conductive material
136
to provide a ground connection between cage
160
and host circuit board
130
. Bottom wall
164
and back wall
166
define an opening for receiving female connector
140
when cage
160
is press fitted onto host circuit board
130
. A series of resilient clips
168
are formed by folding elongated tabs extending from walls
161
,
162
,
163
, and
164
, and are utilized to provide electrical connection between cage
160
and optional bezel
180
. Formed on bottom wall
164
of cage
160
is a transceiver latch
170
that defines a latch opening
175
for receiving boss
152
provided on the lower surface of transceiver housing
151
to secure transceiver
150
inside cage
100
. A series of vent holes are formed on top wall
163
that align with vent holes formed in transceiver housing
151
(discussed above), and cooperate with an optional system ventilation (cooling) system to maintain transceiver
150
at a desired operating temperature. Cage
160
includes dimensions that are consistent with the standards set forth in the Cooperation Agreement, and is discussed in further detail in co-pending U.S. Patent application Ser. No. 09/810,820-6776, entitled “SINGLE-PIECE CAGE FOR PLUGGABLE FIBER OPTIC TRANSCEIVER”, which is incorporated herein by reference.
FIGS.
2
(A) through
2
(D) are simplified partial side views depicting the attachment and subsequent removal of transceiver
150
to/from cage
160
. As indicated in FIGS.
2
(A),
2
(B) and
2
(C), as transceiver
150
is pushed into cage
160
(i.e., between upper wall
163
and lower wall
164
in the direction indicated by arrow A), transceiver latch
170
is pushed downward (i.e., bent away from transceiver housing
151
in the direction indicated by arrow B) by boss
152
until boss
152
enters latch opening
175
, at which point transceiver latch
170
is resiliently biased upward (i.e., in the direction indicated by arrow C; see FIG.
2
(C)). In this latched state, movement of transceiver
150
out of cage
100
(i.e., in the direction of arrow D in FIG.
2
(C)) is prevented by the contact between boss
152
and the inner edge of latch opening
175
. As shown in FIG.
2
(D), subsequent manipulation of latch
170
(e.g., by a manual force F) releases boss
152
from latch opening
175
, thereby allowing removal of transceiver
150
. Ideally, the spring provided on back wall
166
of cage
160
pushes transceiver
150
forward (i.e., in the direction of arrow D) when latch
170
is manipulated as shown in FIG.
2
(D).
A problem associated with the conventional transceiver latching mechanism depicted in FIGS.
2
(A) through
2
(D) is that in highly populated arrangements (i.e., in which many transceiver assemblies are mounted in close proximity), it is often very difficult to manipulate transceiver latch
170
, thereby making it difficult to remove transceiver
150
from cage
160
.
FIG. 3
is a simplified side view showing a “belly-to-belly” configuration in which two transceiver assemblies
100
-
1
and
100
-
2
are mounted on opposite sides of host circuit board
130
. Specifically, a first cage
160
-
1
is mounted on an upper side of host circuit board
130
into which a first transceiver
150
-
1
is inserted, and a second cage
160
-
2
is mounted on a lower side of host circuit board
130
into which a second transceiver
150
-
2
is inserted. Such a “belly-to-belly” arrangement is utilized to facilitate highly populated circuit boards that minimize space requirements. A problem with this and other highly populated transceiver arrangements is that they make accessing and manipulating transceiver latches (e.g., transceiver latches
170
-
1
and
170
-
2
; see
FIG. 3
) very difficult, thereby increasing maintenance costs. Further, manipulation of conventional transceiver latches is not reliable and confusing.
What is needed is a release mechanism for pluggable fiber optic transceivers that is easy to access in highly populated transceiver arrangements, and is both reliable and intuitive.
SUMMARY OF THE INVENTION
The present invention is directed to a release mech
Ahrens Michael E.
Dannenberg Andreas H.
Braden Stanton
Infineon - Technologies AG
Nguyen Son V.
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