U.S. patent application number 16/239197 was filed with the patent office on 2020-07-09 for printed circuit board assembly (pcba) with integrated mounting structure to align and couple to transmitter optical assembly (to.
The applicant listed for this patent is Applied Optoelectronics, Inc.. Invention is credited to Ziliang CAI, Kai-Sheng LIN, Yi WANG.
Application Number | 20200218018 16/239197 |
Document ID | / |
Family ID | 70197991 |
Filed Date | 2020-07-09 |
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United States Patent
Application |
20200218018 |
Kind Code |
A1 |
LIN; Kai-Sheng ; et
al. |
July 9, 2020 |
PRINTED CIRCUIT BOARD ASSEMBLY (PCBA) WITH INTEGRATED MOUNTING
STRUCTURE TO ALIGN AND COUPLE TO TRANSMITTER OPTICAL ASSEMBLY
(TOSA) MODULES
Abstract
The present disclosure is generally directed to an optical
transceiver module that includes a mounting section for aligning
and coupling to associated TOSA modules. In particular, an
embodiment of the present disclosure includes TOSA and ROSA
components disposed on a printed circuit board assembly (PCBA). The
PCBA includes a plurality of grooves at a optical coupling end to
provide a TOSA mounting section. Each of the grooves provides at
least one mating surface to receive and couple to an associated
TOSA module. Opposite the optical coupling end, the PCBA includes
an electric coupling section for coupling to, for example, a
transmit (RX) circuit that provides one or more electrical signals
to drive TOSA modules coupled to the TOSA mounting section.
Inventors: |
LIN; Kai-Sheng; (Sugar Land,
TX) ; WANG; Yi; (Katy, TX) ; CAI; Ziliang;
(Richmond, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Optoelectronics, Inc. |
Sugar Land |
TX |
US |
|
|
Family ID: |
70197991 |
Appl. No.: |
16/239197 |
Filed: |
January 3, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/4246 20130101;
H01S 5/02288 20130101; H01S 5/02236 20130101; G02B 6/4256 20130101;
G02B 6/4281 20130101; G02B 6/4228 20130101 |
International
Class: |
G02B 6/42 20060101
G02B006/42; H01S 5/022 20060101 H01S005/022 |
Claims
1. A laser assembly comprising: a base defined by a plurality of
sidewalls, the base comprising: at least a first surface for
mounting a laser arrangement; an aperture for optically aligning
the laser arrangement with an optical coupling receptacle; and a
male coupling section defined by at least one sidewall of the
plurality of sidewalls, the male coupling section defined by at
least a first mating surface that extends substantially transverse
relative to the first mounting surface and being shaped to
generally correspond with a mating groove defined by an optical
coupling end of a printed circuit board of an optical transceiver
module to edge mount thereto such that the laser assembly extends
from the optical coupling end of the printed circuit board.
2. The laser assembly of claim 1, wherein the base defines a
cavity, and wherein the first surface defines a portion of the
cavity, and wherein the male coupling section is disposed below the
cavity.
3. The laser assembly of claim 1, wherein a laser diode is coupled
to the first surface.
4. The laser assembly of claim 3, wherein the laser diode is
coupled to the first mounting surface by way of a laser submount,
and wherein the laser diode is electrically coupled to the laser
submount.
5. The laser assembly of claim 1, wherein the male coupling section
comprises a second mating surface that extends substantially
transverse relative to the first mating surface, and wherein the
second mating surface is configured to be supported by a surface of
the printed circuit board when coupled thereto.
6. The laser assembly of claim 1, wherein the laser assembly
comprises a laser diode, and wherein the base defines a cavity that
includes a focus lens disposed coaxially with the laser diode.
7. The laser assembly of claim 6, wherein a monitor photodiode is
disposed below a light path that extends from an emission surface
of the laser diode, and wherein the light path is aligned with the
focus lens such that channel wavelengths emitted by the laser diode
intersect with substantially the center of the focus lens.
8. The laser assembly of claim 7, wherein the aperture is coaxially
aligned with the laser diode, and wherein the laser assembly
further includes an optical coupling receptacle coupled to the base
and aligned with the aperture to allow for the light path to extend
from the laser diode through the aperture and into the optical
coupling receptacle for optical coupling with a transmit
waveguide.
9. The laser assembly of claim 1, wherein the first mating surface
comprises a generally arcuate shape.
10. The laser assembly of claim 1, wherein the laser assembly
includes a first and second laser arrangements, the first and
second laser arrangements being disposed opposite each other on the
base and configured to emit different channel wavelengths.
11. The laser assembly of claim 1, wherein the male coupling
section includes top and bottom flanges and a vertical section
adjoining the top and bottom flanges, and wherein the vertical
section is defined at least in part by the first mating
surface.
12. The laser assembly of claim 11, wherein the male coupling
section further includes a tapered surface that transitions to the
vertical section, the tapered surface allowing the laser assembly
to self-align when coupling to an associated groove of a
transceiver module.
13. An optical transceiver, the optical transceiver comprising: a
housing defining a cavity for receiving an optical transceiver
module; and an optical transceiver module disposed at least
partially within the cavity of the housing, the optical transceiver
module comprising: a substrate having a first end that extends to a
second end, the substrate having at least a first mounting surface;
a plurality of mating grooves defined by the first end of the
substrate for coupling to laser assemblies; and a plurality of
laser assemblies, each of the plurality of laser assemblies
comprising: a base that provides at least a first surface for
mounting a laser arrangement and a male coupling section, the male
coupling section defined by at least a first mating surface that
extends substantially transverse relative to the first mounting
surface and is shaped to generally correspond with a mating groove
of the plurality of mating grooves.
14. The optical transceiver of claim 13, wherein the male coupling
section comprises a second mating surface that extends
substantially transverse relative to the first mating surface, and
wherein the second mating surface is configured to be supported by
a surface of the substrate when coupled thereto.
15. The optical transceiver of claim 14, wherein the laser assembly
comprises a laser diode, and wherein the base defines a cavity that
includes a focus lens disposed coaxially with the laser diode.
16. The optical transceiver of claim 15, wherein a monitor
photodiode is disposed below a light path that extends from an
emission surface of the laser diode, and wherein the light path is
aligned with the focus lens such that channel wavelengths emitted
from the laser diode intersect with substantially the center of the
focus lens.
17. The optical transceiver of claim 13, wherein the base of each
of the laser assemblies provides a dual-laser arrangement, wherein
the dual-laser arrangement includes first and second laser
arrangements disposed opposite each other on the base, and wherein
the substrate includes a second mating surface disposed opposite
the first mating surface.
18. The optical transceiver of claim 17, wherein the base edge
mounts to the first end of the substrate such that each laser
assembly mounts to the first end and on to the first and second
mating surfaces of the substrate.
19. The optical transceiver of claim 13, wherein the male coupling
section includes top and bottom flanges and a vertical section
adjoining the top and bottom flanges, and wherein the vertical
section is defined at least in part by the first mating
surface.
20. The optical transceiver of claim 19, wherein the male coupling
section further includes a tapered surface that transitions to the
vertical section, the tapered surface allowing the laser assembly
to self-align when coupling to an associated groove of a
transceiver module.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to optical communication
devices, and more particularly, to a printed circuit board assembly
(PCBA) with mounting section that is configured to align and couple
to transmitter optical subassembly (TOSA) modules.
BACKGROUND INFORMATION
[0002] Optical transceivers are used to transmit and receive
optical signals for various applications including, without
limitation, internet data center, cable TV broadband, and fiber to
the home (FTTH) applications. Optical transceivers provide higher
speeds and bandwidth over longer distances, for example, as
compared to transmission over copper cables. The desire to provide
higher speeds in smaller optical transceiver modules for a lower
cost has presented challenges, for example, with respect to thermal
management, insertion loss, and manufacturing yield.
[0003] Optical transceiver modules generally include one or more
transmitter optical subassemblies (TOSAs) for transmitting optical
signals and one or more receiver optical subassemblies (ROSAs) for
receiving optical signals. In general, TOSAs include one or more
lasers to emit one or more channel wavelengths and associated
circuitry for driving the lasers, i.e., to convert electrical
signals to channel wavelengths. On the other hand, ROSAs include a
demultiplexer and one or more lenses for receiving an optical
signal having multiple channel wavelengths to convert the same into
proportional electrical signals. Existing configurations of optical
transceivers include use of TOSAs and ROSAs with separate housings
to support transmitting and receiving operations, respectively. In
addition, the separate TOSA and ROSA housings may be coupled to
receive and transmit circuitry via, for instance, flexible printed
circuit boards and printed circuit assemblies (PCBAs).
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] These and other features and advantages will be better
understood by reading the following detailed description, taken
together with the drawings wherein:
[0005] FIG. 1 is a block diagram of a multi-channel optical
transceiver, consistent with embodiments of the present
disclosure.
[0006] FIG. 2 is a perspective view of a multi-channel optical
transceiver module for use in the multi-channel optical transceiver
of FIG. 1, in accordance with an embodiment of the present
disclosure.
[0007] FIG. 3 is a side view of the multi-channel optical
transceiver module of FIG. 2, in accordance with an embodiment of
the present disclosure.
[0008] FIG. 4 shows a perspective view of a transceiver module
consistent with an embodiment of the present disclosure.
[0009] FIG. 5-6 collectively show an example substrate suitable for
use in the transceiver module of FIG. 4, in accordance with an
embodiment.
[0010] FIGS. 7A-7F collectively show an example TOSA module
suitable for use in the transceiver module of FIG. 4, in accordance
with an embodiment.
[0011] FIG. 7G shows an example cross-sectional view of the TOSA
module of FIG. 7C taken along the line G-G.
[0012] FIGS. 8A-8E collectively show another embodiment of an
example transceiver module consistent with the present
disclosure.
[0013] FIGS. 9A-9D collectively show an example dual laser assembly
suitable for use in the optical transceiver module of FIG. 8A, in
accordance with an embodiment.
[0014] FIG. 9E shows a cross-sectional view of the TOSA module of
FIG. 9B taken along line E-E, in accordance with an embodiment.
DETAILED DESCRIPTION
[0015] The present disclosure is generally directed to an optical
transceiver module that includes a mounting section for aligning
and coupling to associated TOSA modules, which may be referred to
herein as simply laser assemblies. In particular, an embodiment of
the present disclosure includes TOSA and ROSA components disposed
on a printed circuit board assembly (PCBA). The PCBA includes a
plurality of grooves at a optical coupling end to provide a TOSA
mounting section. Each of the grooves provides at least one mating
surface to receive and couple to an associated TOSA module.
Opposite the optical coupling end, the PCBA includes an electric
coupling section for coupling to, for example, a transmit (RX)
circuit that provides one or more electrical signals to drive TOSA
arrangements coupled to the TOSA mounting section.
[0016] In an embodiment, each TOSA module (or laser assembly)
includes a base with a male coupling section having a generally
arcuate shape that corresponds with the grooves at the optical
coupling end of the PCBA. Alternatively, each TOSA module may
include male coupling section having a substantially "I" beam shape
defined by a web (or vertical section), and top and bottom flanges.
The web may be tapered or otherwise dimensioned to be received by
and couple to an associated groove of the PCBA with the top and
bottom flanges acting as stops to prevent travel of the TOSA module
once inserted into an associated groove. In either case, the male
coupling section includes a plurality of mating surfaces for
coupling to and being supported by the grooves of the PCBA. The
embodiments for a TOSA module disclosed herein, in a general sense,
provide a tongue-and-groove arrangement that permits each TOSA
module to easily self-align into an associated groove/slot for
purposes of coupling the same to electrical terminals of the PCBA
during assembly.
[0017] Each TOSA module base further includes a laser arrangement
that includes, for example, a laser diode driver (LDD), laser diode
(LD), monitor photodiode, filtering capacitor(s), and focusing
lens. The components of the laser arrangement may be disposed
coaxially, or substantially coaxially and be aligned with a
longitudinal center line of an optical coupling receptacle disposed
at one end of the TOSA module base. Each TOSA module may support a
single laser arrangement, or a dual-laser arrangement, whereby each
TOSA module base includes two separate laser arrangements, each
laser arrangement having a separate LDD, LD, monitor photodiode,
focus lens and optical coupling receptacle.
[0018] Accordingly, an optical transceiver module consistent with
the present disclosure has numerous advantages over other
approaches that edge-mount laser assemblies to circuit boards by
simply abutting one end of each laser assembly to an edge of the
circuit board. This approach requires properly aligning each TOSA
module along the X, Y and Z axis to ensure the TOSA module is in a
correct location before securing via wire bonding or other fixation
method. An incorrect placement, even by a few microns, can require
re-alignment and reattachment, which can ultimately reduce yield.
In addition, existing approaches generally include up to four TOSA
modules, e.g., 4-channels, for each optical transceiver module. An
embodiment of the present disclosure includes a dual-laser
arrangement whereby each groove of a PCBA can couple to a single
TOSA module base that provides two separate laser arrangements
capable of emitting different or similar channel wavelengths. The
dual laser arrangement may therefore increase channel density for a
transceiver module, e.g., by a factor of 2, as each PCBA can couple
to and support greater than four (4) channels.
[0019] As used herein, "on-board" in the context of a ROSA
arrangement includes direct or indirect coupling of ROSA components
to a common substrate. The components of the ROSA arrangement may
be coupled to the same surface, or different surfaces of the same
substrate. Likewise, the TOSA components may be coupled to the same
or different surfaces of the substrate. In some cases, the
substrate may include multiple pieces/segments, and this disclosure
is not intended to be limited to a single substrate.
[0020] As used herein, "channel wavelengths" refer to the
wavelengths associated with optical channels and may include a
specified wavelength band around a center wavelength. In one
example, the channel wavelengths may be defined by an International
Telecommunication (ITU) standard such as the ITU-T dense wavelength
division multiplexing (DWDM) grid. This disclosure is equally
applicable to coarse wavelength division multiplexing (CWDM). In
one specific example embodiment, the channel wavelengths are
implemented in accordance with local area network (LAN) wavelength
division multiplexing (WDM), which may also be referred to as LWDM.
The term "coupled" as used herein refers to any connection,
coupling, link or the like and "optically coupled" refers to
coupling such that light from one element is imparted to another
element. Such "coupled" devices are not necessarily directly
connected to one another and may be separated by intermediate
components or devices that may manipulate or modify such
signals.
[0021] The term substantially, as generally referred to herein,
refers to a degree of precision within acceptable tolerance that
accounts for and reflects minor real-world variation due to
material composition, material defects, and/or
limitations/peculiarities in manufacturing processes. Such
variation may therefore be said to achieve largely, but not
necessarily wholly, the stated characteristic. To provide one
non-limiting numerical example to quantify "substantially," minor
variation may cause a deviation of up to and including .+-.5% from
a particular stated quality/characteristic unless otherwise
provided by the present disclosure.
[0022] Referring to the Figures, FIG. 1 illustrates an optical
transceiver module 100, consistent with embodiments of the present
disclosure. The optical transceiver module 100 is shown in a highly
simplified form for clarity and ease of explanation and not for
purposes of limitation. In this embodiment, the optical transceiver
module 100 transmits and receives four (4) channels using four
different channel wavelengths (.lamda.1, .lamda.2, .lamda.3,
.lamda.4) and may be capable of transmission rates of at least
about 25 Gbps per channel. In one example, the channel wavelengths
.lamda.1, .lamda.2, .lamda.3, .lamda.4 may be 1270 nm, 1290 nm,
1310 nm, and 1330 nm, respectively. Other channel wavelengths are
within the scope of this disclosure including those associated with
local area network (LAN) wavelength division multiplexing (WDM).
The optical transceiver 100 may also be capable of transmission
distances of 2 km to at least about 10 km. The optical transceiver
100 may be used, for example, in internet data center applications
or fiber to the home (FTTH) applications.
[0023] In an embodiment, the optical transceiver module 100 is
disposed in a transceiver housing 103. The transceiver housing 103
can be configured with one or more cavities to receive one or more
optical transceiver modules, depending on a desired
configuration.
[0024] The optical transceiver module 100 may include a number of
components to support transceiver operations. The optical
transceiver module 100 may include an optical transceiver substrate
102, a plurality of transmitter optical subassemblies (TOSA)
modules 104 for transmitting optical signals having different
channel wavelengths, transmit connecting circuit 106, a
multi-channel receiver optical subassembly (ROSA) arrangement 108
for receiving optical signals on different channel wavelengths, an
optical fiber receptacle 110 to receive and align a fiber connector
(e.g., a ferrule) with the ROSA, and a receiver connecting circuit
112.
[0025] The optical transceiver substrate 102 includes traces,
connector pads, and other circuitry to support transceiver
operations. The optical transceiver substrate 102 may include TOSA
connector pads 114 (or terminals 114) that enable each of the TOSA
modules 104 to mount and electrically couple to the optical
transceiver substrate 102. The optical transceiver substrate 102
may include traces 116 that couple the TOSA connector pads 114 to
the transmit connecting circuit 106. The optical transceiver
substrate 102 may include traces 118 that electrically couple the
ROSA arrangement 108 to the receiver connecting circuit 112. The
optical transceiver substrate 102 may provide an optical
transceiver module that may be "plugged" into an optical
transceiver cage. Therefore, the transmit connecting circuit 106
and the receiver connecting circuit 112 may electrically couple to
external circuitry of the optical transceiver cage. The optical
transceiver substrate 102 may be manufactured from a multi-layer
printed circuitry board (PCB), although other types of substrates
may be utilized and are within the scope of this disclosure. One
example embodiment of the optical transceiver substrate implemented
as a printed circuit board assembly (PCBA) is discussed in further
detail below.
[0026] Each of the TOSA modules 104 may be configured to receive
driving electrical signals (TX_D1 to TX_D4), convert the electrical
signals to a multiplexed optical signal (e.g., a signal with
channel wavelengths .lamda.1 . . . .lamda.n) and output the same to
a multiplexer (not shown). Each of the TOSA modules 104 may be
electrically coupled to the TOSA connector pads 114 and to the
traces 116 through TOSA module connector pads 120. Each of the TOSA
modules 104 may include a laser diode device and supporting
circuitry. The laser diode devices of the TOSA modules 104 may
include distributed feedback lasers (DFBs), Vertical
External-cavity Surface-emitting lasers (VECSEL) or other suitable
laser devices. In an embodiment, the TOSA modules 104 include a
male coupling end to couple into grooves/slots of an associated
transceiver module substrate, as discussed below.
[0027] As further in shown FIG. 1, the multi-channel ROSA
arrangement 108 includes an optical demultiplexer 124, a
photodetector array 126 (e.g., photodiodes), and a trans-impedance
amplifier (TIA) 128 or amplification circuit 128 for amplifying and
converting optical signals into electrical signals. The
multi-channel ROSA arrangement 108 may be disposed on the substrate
102 in an on-board configuration, whereby each component is coupled
to and supported by the substrate 102. This departs from existing
ROSA approaches which utilize a separate and distinct housing,
often formed from metal, that includes a cavity for receiving
filters/mirrors and other active/passive components for
demultiplexing a multi-channel optical signal into constituent
channel wavelengths.
[0028] Referring to FIGS. 2-6, an example embodiment of an example
optical subassembly module 200 is shown consistent with the present
disclosure. As shown, the optical subassembly module 200 includes a
substrate 202. The substrate 202 may be implemented as the
substrate 102 as discussed above with regard to FIG. 1. The
substrate 202 includes a first end 203 that extends to a second end
205 along a longitudinal axis 250. The substrate 202 further
includes at least a first mounting surface 245 disposed opposite a
second mounting surface 246. A ROSA arrangement 208 is disposed on
the first mounting surface 245 proximate the first end 203 and
includes an on-board or integrated configuration. In the embodiment
of FIG. 2, the ROSA arrangement 208 includes a demultiplexer 224,
e.g., an arrayed waveguide grating, an optical input port 225, and
an optical coupling receptacle 210. One embodiment of the ROSA
arrangement 208 is disclosed and described in greater detail in the
co-pending U.S. patent application Ser. No. 16/142,466 titled
"Receiver Optical Subassembly (ROSA) Integrated on Printed Circuit
Board Assembly (PCBA)", which is incorporated herein in its
entirety.
[0029] Continuing on, a TOSA arrangement 206 is coupled to at least
the second mounting surface 246 proximate the first end of the
substrate 202 and adjacent the ROSA arrangement 208. As discussed
in greater detail below, the TOSA arrangement 206 can include
mating surfaces for directly coupling to and being supported by the
second mounting surface 246. The TOSA arrangement 206 includes a
plurality of laser assemblies, 206-1 to 206-4, configured to launch
a plurality of associated channel wavelengths
(.lamda..sub.1-.lamda..sub.4) on to external transmit optical
waveguides 207, e.g., optical fibers. As shown, each of the laser
assemblies 206-1 to 206-4 include a base that allows for edge
mounting via an associated groove of the plurality of grooves 252
provided by the optical coupling end 203 of the substrate 202,
which will be discussed in further detail below. The plurality of
grooves 252 may also be referred to as a TOSA mounting section. The
grooves 252 may be formed by the substrate 202, and thus, the
grooves 252 and substrate 202 may be a single piece. However, this
disclosure is not limited in this regard and the substrate 202 and
grooves 252 may be different pieces.
[0030] With specific reference to FIGS. 4-6, the substrate 202 may
comprise, for example, a printed circuit board assembly (PCBA),
such as shown, or other suitable substrate configuration. The
optical coupling end 203 of the substrate 202 defines a plurality
of grooves 252 which may also be referred to as notches. The
grooves shown collectively as 252 and individually as 252-1 to
252-4 may be evenly spaced relative to each other to allow for the
laser assemblies 206-1 to 206-4 to be disposed relatively close in
proximity to each other. Each of the plurality of grooves 252
provide a female portion for mating and coupling to corresponding
male portions of each of the laser assemblies 206-1 to 206-4. This
allows the plurality of grooves 252 and laser assemblies 206-1 to
206-4 to form a tongue and groove arrangement. In some cases, the
substrate 202 may provide male ends for mating to a female end of
each of the laser assemblies 204-1 to 204-4, so the embodiment of
FIG. 4 should not be construed as limiting.
[0031] In any event, the plurality of grooves 252 may be configured
to align each of the laser assemblies along the X, Y and Z axis
during assembly of the optical subassembly module 200. Each of the
grooves 252 provides at least a first mating surface 256-1 and a
second mating surface 256-2 that extend substantially transverse
relative to each other. Each of the first and second mating
surfaces 256-1 and 256-2 can provide a stop feature that limits
travel about the X, Y and Z axis. For example, as shown the laser
assembly 204-4 may be aligned and inserted into the associated
groove 252-4 such that the male coupling section of the laser
assembly 206-4 directly abuts the first mating surface 256-1
defined by the groove 252-4 and directly contacts and is supported
by the second mating surface 256-2. Therefore, the first and second
mating surfaces 256-1, 256-2 of each of the grooves 252 allow for
an associated laser assembly to be easily aligned with, and
securely coupled, to the substrate 202. This tongue-and-groove
arrangement also aligns each laser assembly with electrical
contacts 258 of the substrate 202 for electrical coupling via, for
instance, wire bonds 259. Each of the laser assemblies 206-1 to
206-4 may then be attached to the substrate 202 via, for example,
welds or other suitable method.
[0032] FIGS. 7A-7G collectively show one example of a laser
assembly 206-N consistent with an embodiment of the present
disclosure. The laser assembly 206-N may also be referred to as a
cuboid laser assembly. The laser assembly 206-N includes a base
portion 708 or cuboid base portion 708, which may be referred to as
simply a base. The base 708 includes an upper portion that includes
a notch/cavity 706 defined by sidewalls of the base 708. The cavity
706 provides at least a first mounting surface 709-1 (see FIGS. 7E
and 7F). As further shown, a laser diode (LD) sub-mount 710 couples
to the first mounting surface 709-1. The LD sub-mount 710 may
comprise, for example, a printed circuit board (PCB) with a
plurality of traces 714, as shown. A laser diode 712 is mounted on,
and electrically couples to, the LD sub-mount 710 by way of wire
bonding, for example. The laser diode 712 may comprise an edge
emitting diode configured to emit channel wavelengths along an
optical path 716 that intersects with one or more passive or active
optical components disposed within the base 708 and the optical
coupling receptacle 704. For example, as shown in the
cross-sectional view of FIG. 7G, the optical path 716 extends
through the focus mirror 718, aperture 723, optical isolator 722
and fiber stub 724. This configuration may also be referred to as a
colinear arrangement whereby the laser diode 712, monitor
photodiode 730, lens 718, aperture 723, and optical coupling
receptacle are disposed along a common axis. The optical coupling
receptacle 704 may be sized to allow for insertion of a ferrule to
allow for optical coupling with a transmit optical waveguide, e.g.,
an optical fiber.
[0033] Continuing on, the base 708 of the laser assembly 206-N
further includes a lower portion 727 that defines a male coupling
section 711 (See FIG. 7B). As shown, the male coupling section 711
includes a generally arcuate profile/shape that corresponds with
the female coupling section defined by the plurality of grooves 252
of the substrate 202. In particular, a first mating surface 713-1
defines the generally arcuate shape and is contoured to generally
correspond with the first mating surface 256-1 that defines each of
the plurality of grooves 252. Therefore, the male coupling section
711 and the female coupling section, e.g., the grooves 252, of the
substrate 202 may form a tongue and groove or "keyed"
configuration.
[0034] The male coupling section 711 further includes a shoulder
that is at least partially defined by a second mating surface
712-2. As previously discussed, each of the laser assemblies can
include a portion that rests on the substrate 202, and in
particular, the second mating surface 256-2. The second mating
surface 712-2 of the laser assembly 206-N may be substantially flat
and dimensioned to at least partially allow for direct contact with
the second mating surface 256-2 of the substrate 202. To this end,
the first mounting surface 245 of the substrate 202 may support at
least a portion of the base 708 of the laser assembly 206-N based
on the second mating surface 256-2.
[0035] Continuing on, the laser assembly 206-N further defines a
second mounting surface 709-2 within the cavity 706 (See FIG. 7F).
The first and second mounting surfaces 709-1, 709-2 may define a
step/shoulder based on a surface 726 that extends substantially
transverse relative to each of the first and second mounting
surfaces 709-1, 709-2 and adjoins the same, which is shown more
clearly in FIG. 7G. The surface 726 includes a predefined height
that allows a monitor photodiode sub-mount 728 and monitor
photodiode 730 to be mounted in a countersunk arrangement whereby
the monitor photodiode is disposed between the laser diode 712 and
focus lens 718, but does not substantially obstruct channel
wavelengths emitted along light path 716. In addition, the
countersunk arrangement further allows the light path 716 to
intersect with the focus lens 718 substantially at a center of the
same.
[0036] Note that while the embodiments of FIGS. 5-7G show an
arrangement whereby laser assemblies have a male coupling section
and the substrate 202 includes a female coupling section, this
disclosure is not necessarily limited in this regard. For example,
the substrate 202 may include a male coupling section and each
laser assembly may include a female coupling section, depending on
a desired configuration.
[0037] FIGS. 8A-8E collectively show another example of an optical
subassembly module 800 in accordance with an embodiment of the
present disclosure. As shown, the optical subassembly module 800
includes a substrate 802 that extends from a first end 805 to a
second end 807 along a longitudinal axis 850. A plurality of dual
laser assemblies 806 are edge mounted to the second end 806. Note
that the embodiment shown in FIG. 8A is illustrated without a ROSA
arrangement not for purposes of limitation but for reasons of
clarity. The optical subassembly module 800 may be configured
substantially similar to that of the optical subassembly module 200
discussed above with reference to FIGS. 2-3, and for this reason
the description of which will not be repeated for brevity. However,
the embodiment of FIG. 8A includes a plurality of dual laser
assemblies 804 that provides two 1.times.4 arrays of dual laser
assemblies to provide a total of eight (8) channels. The dual laser
assemblies therefore advantageously increasing channel density for
the optical subassembly module 800.
[0038] In particular, each of the dual laser assemblies 806 include
a mounting portion configured to couple into grooves 852 (FIG. 8E)
of the substrate 802, which is discussed below in further detail.
As further shown, the plurality of dual laser assemblies 806 mount
to the first and second mounting surfaces 845, 846 to securely hold
the plurality of dual laser assemblies in place. During
manufacturing of the optical subassembly module 800, the plurality
of laser assemblies 806 may be individually coupled to respective
grooves of the plurality of grooves 852 with alignment provided by
their respective base portion that provides an interlocking
arrangement. The grooves 852 may be disposed at predefined
locations and spacing relative to each other to allow for
relatively easy alignment along the X, Y and Z axis of associated
dual laser assemblies. Notably, the structure of the dual laser
assemblies 806 ensures proper alignment about each of the X, Y and
Z axis by limiting travel. Accordingly, attachment during
manufacture may be performed by simply coupling the dual laser
assemblies 806 into grooves 852.
[0039] A heating element 811 (FIG. 8D) may be disposed on the
plurality of dual laser assemblies 806. The heating element 811 may
be utilized to stabilize emitted channel wavelengths by adjusting
temperature. The heating element 811 may comprise a coil, as shown,
or other suitable device.
[0040] FIG. 9A shows an example dual laser assembly 806-N in
isolation for ease of description and clarity. As shown, the dual
laser assembly 806-N includes a base 908 having a first end 905
that extends to a second end 906. The first end 905 may be
electrically coupled to an associated transmit connecting circuit
(not shown), and therefore may also be referred to as an electrical
coupling end. On the other hand, the second end 906 is proximate
optical fiber coupling receptacles 909-1, 909-2, and therefore may
be referred to as an optical coupling end.
[0041] The base 908 includes at least first and second mounting
sections 901-1, 901-2 disposed opposite each other to mount to
first and second laser arrangements 956-1, 956-2, respectively. In
an embodiment, the first and second mounting sections 901-1, 902-2
and associated laser arrangements may be substantially symmetrical
to provide a dual laser arrangement. For instance, the embodiment
of FIG. 9D illustrates how the base 908 provides a substantially
symmetric profile/shape about the top and bottom portions of the
base 908, with the first and second laser arrangements 956-1, 956-2
being substantially mirror images of each other.
[0042] With specific reference to FIGS. 9A-9C, the first laser
mounting section 901-1 includes a first mounting surface 910-1 for
mounting to active and/or passive optical components that extends
parallel with a longitudinal axis of the optical fiber coupling
receptacles 909-1, 909-2. As shown, the mounting section 901-1
further includes a laser diode driver (LDD) submount 910-1. The LDD
submount 910-1 includes a LDD chip 931-1 mounted and electrically
coupled thereto. Likewise, the LDD submount 910-1 includes first
and second filtering capacitors 932-1, 932-1 mounted and
electrically coupled thereto. The mounting section 901-1 further
includes a first laser diode 930-1 mounted to the first mounting
surface 901-1 and disposed between the LDD submount 910-1 and the
focus lens 918-1. Following the LDD submount 910-1 is a recessed
mounting region 920-1. As discussed further below, the recessed
mounting section 920-1 provides a countersunk arrangement which
allows for the first focus lens 918-1 to have a center
substantially aligned with an emission surface/face of the laser
diode 930-1.
[0043] The second laser mounting section 901-2 includes a first
surface 910-2 for mounting to active and/or passive optical
components that extends parallel with a longitudinal axis of the
optical fiber coupling receptacles 909-1, 909-2. As shown, the
second mounting section 901-2 includes a laser diode driver (LDD)
submount 910-2. The LDD submount 910-2 includes a LDD chip 931-2
mounted and electrically coupled thereto. Likewise, the LDD
submount 910-2 includes first and second filtering capacitors
932-3, 932-4 mounted and electrically coupled thereto. The second
laser mounting section 901-2 further includes a laser diode 930-2
mounted to the second mounting surface 901-2 and disposed between
the LDD submount 910-2 and the focus lens 918-2. Following the LDD
submount 910-2 is a recessed mounting region 920-2. The recessed
mounting section 920-2 provides a countersunk arrangement which
allows for the second focus lens 918-2 to have a center
substantially aligned with an emission surface/face of the laser
diode 930-2.
[0044] As discussed above, the each dual laser assembly can easily
couple into corresponding grooves of the plurality of grooves 952
to mount to the substrate 902. One example mounting section 980 is
shown in greater detail in FIGS. 9A, 9B and 9D. With specific
reference to FIG. 9D, the mounting section 980 is defined by the
base 908 and includes first and second sidewalls 962-1, 962-2,
disposed opposite each other. Each of the first and second
sidewalls 962-1, 962-2 support the first and second mounting
surfaces 901-1, 901-2 and are defined by surfaces that extend
substantially transverse relative to the same. The first and second
sidewalls 962-1, 962-2 transition to first and second tapered
sidewalls 964-1, 964-2, respectively. A mating surface 965 adjoins
the first and second tapered sidewalls 964-1, 964-2.
[0045] The base 908 may therefore provide a so-called "I" or "EYE"
beam shape that includes top and bottom flanges 970-1, 970-2 which
are connected by a middle section or web at 965. The taper of the
middle section allows the base 908 to self-align into an associated
groove of the plurality of grooves 952. The mating surface 965 may
therefore directly abut or otherwise be in close proximity to the
substrate 902 when the base 908 is inserted into an associated
groove. The first and second tapered sidewalls 962-1, 962-2 and/or
the first and second sidewalls 964-1, 964-2 may also directly abut
the substrate 902 or otherwise be in close proximity, and may
therefore may also provide additional mating surfaces to securely
hold the dual laser assembly 806-N in an associated groove of the
plurality of grooves 952.
[0046] Turning to FIG. 9E, a cross-sectional view of the dual laser
assembly 806-N taken along the line E-E (See FIG. 9B) is shown in
accordance with an embodiment. As shown, the first laser mounting
section 901-1 includes a first laser arrangement 944-1. The first
laser arrangement 944-1 includes a first LDD chip 931-1, first
laser diode 930-1, and a first monitor photodiode 929-1. The second
laser mounting section 901-2 includes a second laser arrangement
944-2. The second laser arrange 944-2 includes a second LDD chip
931-2, second laser diode 930-2, and a second monitor photodiode
929-2. The first and second laser arrangements 944-1, 944-2 are
configured to launch an associated channel wavelength on to first
and second optical paths 916-1, 916-2, respectively. The first and
second optical paths 916-1, 916-2 may extend substantially parallel
to each other and extend through a plurality of active and/or
passive optical components before being launched onto, for example,
an external transmit fiber. For example, the first optical path
916-1 extends through the first aperture 909-1, a first optical
isolator 922-1, and a first fiber stub 924-1. Likewise, the second
optical path 916-2 extends through a second aperture 909-2, a
second optical isolator 922-2 and a second fiber stub 924-2. The
embodiment shown in FIG. 9E may be referred to as a collinear
arrangement whereby each of the LDD chip, laser diode, monitor
photodiode are disposed along the same axis.
[0047] One aspect of the present disclosure includes a laser
assembly. The laser assembly comprising a base defined by a
plurality of sidewalls, the base comprising at least a first
surface for mounting a laser arrangement, an aperture for optically
aligning the laser arrangement with an optical coupling receptacle,
and a male coupling section defined by at least one sidewall of the
plurality of sidewalls, the male coupling section defined by at
least a first mating surface that extends substantially transverse
relative to the first mounting surface, the male coupling section
being shaped to generally correspond with a mating groove of a
printed circuit board of an optical transceiver module.
[0048] Another aspect of the present disclosure includes an optical
transceiver. The optical transceiver comprising a housing defining
a cavity for receiving an optical transceiver module, and an
optical transceiver module disposed at least partially within the
cavity of the housing, the optical transceiver module comprising, a
substrate having a first end that extends to a second end, the
substrate having at least a first mounting surface, a plurality of
mating grooves at the first end of the substrate for coupling to
laser assemblies, and a plurality of laser assemblies, each of the
plurality of laser assemblies comprising a base that provides at
least a first surface for mounting a laser arrangement and a male
coupling section, the male coupling section defined by at least a
first mating surface that extends substantially transverse relative
to the first mounting surface and is shaped to generally correspond
with a mating groove of the plurality of mating grooves.
[0049] While the principles of the disclosure have been described
herein, it is to be understood by those skilled in the art that
this description is made only by way of example and not as a
limitation as to the scope of the disclosure. Other embodiments are
contemplated within the scope of the present disclosure in addition
to the exemplary embodiments shown and described herein.
Modifications and substitutions by one of ordinary skill in the art
are considered to be within the scope of the present disclosure,
which is not to be limited except by the following claims.
* * * * *