Opto-electronic device suitable for reflow soldering

Abstract

Embodiments include an opto-electronic device (OED). The OED includes a substrate having mounted thereon one or more active optical devices. The substrate includes a bottom surface with a plurality of electrically conductive contacts configured for attachment to a printed circuit board (PCB) assembly via a reflow soldering process. The OED includes a first optical coupling device that includes a top surface and is located above a top surface of the substrate. The OED includes one or more first lenses optically aligned with the respective one or more active optical devices mounted on the substrate, and a second optical coupling device including a bottom surface and one or more second lenses. The bottom surface of the second optical coupling device is arranged against the top surface of the first optical coupling device such that the one or more second lenses are optically aligned with the respective one or more first lenses.

Description

[0001] OPTO-ELECTRONIC DEVICE SUITABLE FOR REFLOW SOLDERING

[0002] TECHNICAL FIELD

[0003] The present application relates generally to the field of optical communications, and more specifically to opto-electronic devices (OEDs), or sub-assemblies thereof, that can be mounted on a standard printed circuit board (PCB) using reflow soldering processes.

[0004] BACKGROUND

[0005] In wavelength division multiplexed optical communication systems, many different optical wavelength carriers provide independent communication channels in a single optical fiber. Future computation and communication systems place ever-increasing demands upon communication link bandwidth. It is generally known that optical fibers offer much higher bandwidth than conventional coaxial communications. Furthermore, a single optical channel in a fiber waveguide uses a very small fraction of the available bandwidth of the fiber - typically a few Gigahertz (GHz) out of several tens of Terahertz (THz) available. By transmitting several channels at different optical wavelengths into a fiber - typically referred to as “wavelength division multiplexing” or “WDM” - this bandwidth may be utilized more efficiently.

[0006] In typical operation, an optical multiplexing device (also referred to as “optical coupler,” “optical transceiver,” or more generally “opto-electronic device”) combines or separates multiple light signals with varying optical frequencies or, equivalently, wavelengths. Optical multiplexing devices have applications for both dense and coarse wavelength division multiplexing (DWDM and CWDM) for both multi-mode and signal-mode fiber optic data communications and telecommunications. Multiple-wavelength light sources can be combined into a single optical path for transmission, or multi-wavelength light travelling in a single optical path can be separated into multiple narrow spectral bands that can be focused onto individual fiberoptic carriers or detectors.

[0007] As used herein, the term “opto-electronic device” generally refers to a device that operates on optical signals of one or more wavelengths, and includes active devices such as lasers and / or photodiodes, other electronics, and lenses typically made from plastic. The terms “optical coupler” and “optical transceiver” are two types of opto-electronic devices. The term “optical multiplexing device” is also a type of opto-electronic device, but specifically one that multiplexes (and / or demultiplexes) multiple optical signals of different wavelengths or frequencies. SUMMARY

[0008] Even so, there arc some challenges in the manufacturing of opto-clcctronic devices (OEDs). In many different applications, it would be preferred to assemble an opto-electronic device in an integrated circuit (IC) platform using standard printed circuit board (PCB) assembly including solder reflow. However, conventional OEDs with integrated plastic lensing systems are not designed to survive a solder reflow process.

[0009] An object of embodiments of the present disclosure is to address these and other problems, issues, and / or difficulties related to OED manufacturing, thereby facilitating less costly OED assembly using solder reflow techniques commonly used in assembly of non-OEDs.

[0010] Some embodiments of the present disclosure include an opto-electronic device (OED). The OED includes a substrate having mounted thereon one or more active optical devices. The substrate includes a bottom surface having a plurality of electrically conductive contacts configured for attachment to a printed circuity board (PCB) assembly via a reflow soldering process. The OED includes a first optical coupling device located above a top surface of the substrate and one or more first lenses that are optically aligned with the respective one or more active optical devices mounted on the substrate. The first optical coupling device includes a top surface (e.g., a planar surface).

[0011] The OED also includes a second optical coupling device comprising a bottom surface (e.g., a planar surface) and one or more second lenses. The bottom surface of the second optical coupling device is against the top surface of the first optical coupling device such that the one or more second lenses are optically aligned with the respective one or more first lenses.

[0012] In some embodiments, the one or more first lenses are attached to or integrated into the top surface of the first optical coupling device. In other embodiments, the one or more first lenses are attached to or integrated into a bottom surface of the first optical coupling device. In other embodiments, the first optical coupling device comprises a first part and a second pail, a bottom surface of the second part is arranged against a top surface of the first part, and the top surface of the first part includes a recess in which the one or more first lenses are located.

[0013] In other embodiments, the one or more first lenses are attached to or integrated into top surfaces of the respective active optical devices, while bottom surfaces of the respective active optical devices are mounted to the substrate. In other embodiments, the one or more first lenses are attached to or integrated into a first side of a second optically transparent substrate, the one or more active optical devices are attached to a second side of the second optically transparent substrate, and the second side of the second optically transparent substrate includes a second plurality of electrically conductive contacts that are attached to the substrate.

[0014] Other embodiments and variants of the exemplary OED apparatus are described herein.

[0015] Other embodiments include methods for assembling an OED that includes a substrate, a first optical coupling device, one or more first lenses, and a second optical coupling device. Such methods include attaching a bottom surface of the second optical coupling device to a top surface of the first optical coupling device, such that the one or more second lenses of the second optical coupling device are optically aligned with the respective one or more first lenses.

[0016] Such methods include subsequently attaching a bottom surface of the first optical coupling device to a top surface of the substrate, such that the one or more first lenses are optically aligned with respective one or more active optical devices mounted on the substrate. Such methods include subsequently removing the bottom surface of the second optical coupling device from the top surface of the first optical coupling device, and then attaching a plurality of electrically conductive contacts on a bottom surface of the substrate to a printed circuit board (PCB) using a reflow soldering process. Such methods include subsequently reattaching (i.e., after reflow soldering) the bottom surface of the second optical coupling device to the top surface of the first optical coupling device, such that the one or more second lenses are optically aligned with the respective one or more first lenses and the respective one or more active optical devices.

[0017] These and other disclosed embodiments can provide various benefits and / or advantages. Embodiments can facilitate efficient assembly of OEDs using well-known, cost-efficient reflow soldering processes, thereby reducing overall cost of manufactured OEDs. Moreover, by use of molded monolithic optical coupling devices with integrated optical alignment features, embodiments reduce the number of discrete parts needed for OEDs, thereby reducing cost of assembly.

[0018] These and other objects, features, and advantages of the present disclosure will become apparent upon reading the following Detailed Description in view of the Drawings briefly described below.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figures 1-2 show different pre-assembly views of an OED according to some embodiments of the present disclosure. Figure 3 shows a cross-sectional view of an assembly of the OED shown in Figures 1 -2.

[0021] Figure 4 shows a bottom oblique view of an assembly of the OED shown in Figures 1-2.

[0022] Figure 5 illustrates exemplary operation of first and second optical coupling devices of various disclosed embodiments of an OED.

[0023] Figure 6 shows a pre-assembly view of an OED according to other embodiments of the present disclosure.

[0024] Figure 7 shows a cross-sectional view of an assembly of the OED shown in Figure 6.

[0025] Figures 8-9 show different pre-assembly views of an OED according to other embodiments of the present disclosure.

[0026] Figure 10 shows a cross-sectional view of an assembly of the OED shown in Figures 8-9.

[0027] Figure 11 shows an internal view of encapsulated components shown in Figures 8-9.

[0028] Figure 12 shows a top view of sub-assembly of the OED shown in Figures 8-9.

[0029] Figure 13 shows a side view of another sub-assembly of the OED shown in Figures 8-9.

[0030] Figures 14-15 show different pre-assembly views of an OED according to other embodiments of the present disclosure.

[0031] Figure 16 shows a cross-sectional view of an assembly of the OED shown in Figures 14- 15.

[0032] Figures 17-18 show top and side views of different sub-assembly options for the OED shown in Figures 14-15.

[0033] Figure 19 shows a substrate carrying laser and photodiode components with integrated lenses, according to some embodiments of the present disclosure.

[0034] Figures 20 shows a substrate with laser, photodiode, and lens components mounted thereon or integrated therein, according to some embodiments of the present disclosure.

[0035] Figures 21-22 show side views of different OED sub-assembly variants according to other embodiments of the present disclosure.

[0036] Figure 23 shows an exemplary method for assembling an OED, according to various embodiments of the present disclosure.

[0037] DETAILED DESCRIPTION

[0038] Embodiments briefly summarized above will now be described more fully with reference to the accompanying drawings. These descriptions are provided by way of example to explain the subject matter to those skilled in the art and should not be construed as limiting the scope of the subject matter to only the embodiments described herein. More specifically, examples are provided below that illustrate the operation of various embodiments according to the advantages discussed above.

[0039] In general, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The operations of any methods and / or procedures disclosed herein do not have to be performed in the exact order disclosed, unless an operation is explicitly described as following or preceding another operation and / or where it is implicit that an operation must follow or precede another operation. Any feature of any embodiment disclosed herein can apply to any other disclosed embodiment, as appropriate. Likewise, any advantage of any embodiment described herein can apply to any other disclosed embodiment, as appropriate.

[0040] As briefly mentioned above, there are some challenges in the manufacturing of optoelectronic devices (OEDs). In many different applications, it would be preferred to assemble an opto-electronic device in an integrated circuit (IC) platform using standard printed circuit board (PCB) assembly techniques including reflow soldering. In particular, reflow soldering is a process in which a solder paste is used to temporarily attach electrical components to their contact pads on a PCB (or other substrate) at room temperature. Subsequently, when the assembly is subjected to controlled heat, the solder paste reflows into a molten state, creating permanent solder joints. The controlled heating is typically done by passing the assembly through a reflow oven or putting it under a heat lamp (e.g., infrared).

[0041] Electronics assembly by reflow soldering is a well-understood process that can be highly automated and, thus, cost-efficient. However, conventional OEDs with integrated plastic lens systems are not designed to survive the heat used in a reflow soldering process. Rather, these OEDs must be assembled using more expensive processes that are less automated. Accordingly, there is an unmet need for OEDs designed to be assembled using cost-efficient reflow soldering.

[0042] Embodiments of the present disclosure address these and related problems, issues, and / or difficulties by various configuration of single-wavelength, multi-wavelength, and array OEDs that include an optical substrate (or platform) and collimating optics (e.g., lenses), that can be constructed in various way that facilitate the optical substrate platform and collimating optics to be reflow soldered using standard PCB assembly processes. The final optical fiber connection can then be made with a single connecting component that attaches to the OED assembled in this manner.

[0043] At a high level, embodiments include an OED (e.g., optical transceiver, optical multiplexer) configured to transmit and / or receive optical signals of similar or different wavelengths. The OED collimates a single light source or array of light sources, directs the collimated light to propagate along a path (or similar' paths), which couples into an optical fiber through a single lens or an array of lens.

[0044] The OED may contain a substrate assembly of active optical devices (e.g., lasers and / or photodiodes), electronic devices, and collimating lenses on or attached to a substrate. An exterior surface (e.g., bottom) of the substrate assembly includes electrically conductive contacts (e.g., balls, leads, micro-lead frame, etc.) that are configured for attachment to a larger PCB assembly using a reflow soldering process (e.g., reflow oven). For example, the electrically conductive contacts may be on a bottom side of a substrate, with the active optical devices, electronic devices, and / or collimating lenses being mounted on a top side of the substrate. The electrically conductive contacts are connected to one or more of the electronic devices, e.g., via wiring printed on the substrate.

[0045] In various embodiments, the OED may include one or more optical coupling devices that can be arranged in various ways to achieve the desired effects. One example is a plastic injection moulded optical coupling device that contains all necessary opto-mechanical alignment features (e.g., mirrors), an array of collimating lenses, and an attachment mechanism for attaching to the substrate assembly prior to reflow soldering. A second optical coupling device can be attached to the assembly after reflow soldering. The second optical coupling receives collimated light from the first optical coupling device and directs it to one or more optical fibers, and / or collimates light received from one or more optical fibers and directs it to the first optical coupling device. Other examples are discussed below with reference to various figures.

[0046] Embodiments may provide various benefits and / or advantages. For example, embodiments facilitate efficient assembly of OEDs using well-known, cost-efficient reflow soldering processes, thereby reducing overall cost of manufactured OEDs. Moreover, by use of moulded monolithic optical coupling devices with integrated optical alignment features, embodiments reduce the number of discrete parts needed for OEDs, thereby reducing cost of assembly.

[0047] Figures 1-2 show different pre-assembly views of an OED (100), according to some embodiments of the present disclosure. Figure 3 shows a cross-sectional view of an assembly of the OED shown in Figures 1-2. Figure 4 shows a bottom oblique view of an assembly of the OED shown in Figures 1-2. The following description refers to these figures.

[0048] Substrate (1, also referred to as “Stratum- 1”) may be a planar (or flat) multi-layer PCB constructed of laminate dielectric, ceramic, or other materials so as to provide a planar top surface for mounting of active optical devices, such as vertically-emitting lasers (8) and photodiodes (10), as well as electronic devices (7) that interface with and / or control the active optical devices. A bottom surface of substrate (1) also includes electrically conductive contacts (9) arranged to connect the substrate to a larger PCB assembly. The electrically conductive contacts are shown as balls in a Ball-Grid- Array (BGA), but may also be configured as a Pin- Grid- Array (PGA) or a Flat-No-Lead array.

[0049] In this embodiment, a first optical coupling device (2, also referred to as “Stratum-2”) is physically attached to substrate (1) with adhesive, welding, fusing, or any other technique that would provide secure attachment. The first optical coupling device (2) includes a single lens or lens array (13) molded into either its bottom (i.e., towards substrate) or top (i.e., opposite from substrate) surface such that each lens can be optically aligned with a corresponding laser (8) or photodiode (10) on substrate (1). Each lens (13) can be arranged to redirect, collimate, slightly diverge, or slightly converge, the light being input from the corresponding laser (8) or output to the corresponding photodiode (10), as the case may be.

[0050] According to the embodiments illustrated in Figure 3, the bottom surface of the first optical coupling device has a recessed area in which lens array (13) is located. Moreover, the bottom surface of the first optical coupling device is against the top surface of the substrate, such that the recessed area surrounds the one or more active optical devices mounted to the substrate.

[0051] A second optical coupling device (3, also referred to as “Stratum-3) mounts to the first optical coupling device (2) such that the bottom surface (17b) of the second optical coupling device and the top surface (17a) of the first optical coupling device are parallel and against each other. The two surfaces (17a,b) may be planar and may be held together by compression force, which may be provided by a cover (5) that includes a first part of a latching mechanism (11, e.g., clip) that mates with a corresponding second part of the latching mechanism (11 ) on the first optical coupling device (2). However, other mechanical structures that compresses the surfaces (17a, b) against each other may be used. Note that when the first optical coupling device is attached to the substrate and the second optical coupling device is compressed against it, the surfaces (17a, b) may be co-planar and parallel to the planar surface of the substrate (1).

[0052] A package housing (6) may be assembled on the outside of the cover (5), and may substantially surround the cover (e.g., except for opening needed for ingress of optical fibers). The second optical coupling device (3) includes a single lens or an array of lenses (14) that are optically coupled to the corresponding lens(es) of the first optical coupling device (2) and to one or more optical fibers (12). The single lens or array lens (14) is molded into the bottom (i.e., towards first optical coupling device) surface of the second optical coupling device (3). The optical fibers may be coupled to the package housing (6) by a mechanical strain relief (4) device.

[0053] Figure 5 illustrates combined optical operation of the first and second optical coupling devices in these embodiments. Light enters (or exits) a first surface of the first optical coupling device (2) at a first focal point (50), which may be directly coupled to active optical devices (8, 10). Light exits (or enters) a second surface of the first optical coupling device (2) as collimated beam(s) (49), which enter (or exit) a first surface of the second optical coupling device (3) and exit (enter) a second surface of the second optical coupling device (3) at a second focal point (51). The second focal point may be directly coupled to an optical fiber (12). The collimated beam between the first and second optical coupling devices reduces alignment requirements and improves tolerance to dust and / or debris.

[0054] The second optical coupling device (3) also includes a redirection optic (15, e.g., total internal reflector) that redirects light to / from the one or more optical fibers (12), which may be attached to the second optical coupling device via respective one or more mounting surfaces (16). In some embodiments, the redirection optic may include an integrated coupling lens to focus light to the optical fiber(s) or collimate light from the optical fiber(s).

[0055] In the embodiments shown in Figures 1-4, the alignment of the first and second optical coupling devices only requires the two corresponding surfaces (17) to be parallel. The horizontal placement of the first and second optical coupling devices is less critical such that standard mechanical guiding mechanisms can be used for more precise alignment during assembly.

[0056] In the embodiments shown in Figures 1-4, assembly can be performed with a solder reflow process and after assembly, the second optical coupling device (3) can be physically connected with no precision alignment necessary. Moreover, the second optical coupling device (3) can be physically connected and disconnected as needed.

[0057] Figure 6 shows a pre-assembly view of an OED according to other embodiments of the present disclosure. Figure 7 shows a cross-sectional view of an assembly of the OED shown in Figure 6. The following description refers to these figures.

[0058] In these embodiments, the substrate (1) - including devices (7, 8, 10) mounted thereon and contacts (9) - and the first optical coupling device (2) can be identical to those described above with respect to Figures 1-4. However, a second optical coupling device (18) is configured to direct light to / from the first optical coupling device (2) vertically instead of horizontally as done by the second optical coupling device (3) shown in Figures 1-4. The second optical coupling device (18) includes a single lens or lens array (21) moulded into its bottom surface (i.e., towards the first optical coupling device). The vertical direction of light is accomplished by directly aligning the active optical devices (7, 10), lens array (13), and lens array (21) such that a redirection optic is not used.

[0059] Like embodiments shown in Figures 1-4, the embodiments shown in Figures 6-7 include a cover (19) that compresses the top surface (17a) of the first optical coupling device (2) and the bottom surface (17b) of the second optical coupling device (18). The compression force may be provided by a first part of a clip mechanism (11) on the cover (19) that mates with a corresponding second part of the clip mechanism (11) on the first optical coupling device (2). A package housing (20) may be assembled on the outside of the cover (19) and may substantially surround the cover (e.g., except for opening needed for ingress of optical fibers). The optical fibers (12) may be coupled to the package housing (20) by a mechanical strain relief (4) device.

[0060] The first optical coupling device (2) and second optical coupling device (18) shown in Figures 6-7 can operate according to the principles illustrated in Figure 5.

[0061] Figures 8-9 show different pre-assembly views of an OED (800) according to other embodiments of the present disclosure. Figure 10 shows a cross-sectional view of an assembly of the OED according to these embodiments. The following description refers to these figures.

[0062] In these embodiments, the second optical coupling device (3) can be identical to the corresponding feature shown in Figures 1-4. However, the substrate (1) has an optically clear encapsulate (22) molded over any active optical devices (8, 10) and electronic devices (7) mounted on the top surface. Figure 11 shows an internal view of the encapsulated components.

[0063] The top surface of the encapsulate (22) is planar, and is aligned with and coupled to a corresponding planar bottom surface of the first optical coupling device (23). The top surface of the encapsulate (22) includes a single lens or array lens (24) molded therein (e.g., recessed slightly), such that each lens can be optically aligned with a corresponding laser (8) or photodiode (10) on substrate (1). As an alternative, the encapsulate (22) can be made of a glass with integrated lens (24) and resin package for mounting to the substrate (1). As another alternative, the encapsulate (22) and the lens (24) can be separate parts, with the lens (24) mounted in the encapsulate (22) using an adhesive that has a matching optical index.

[0064] Figure 12 shows a top view of a sub-assembly of substrate (1), encapsulate (22), and first optical coupling device (23) according to these embodiments. Each lens (24) can be arranged to redirect, collimate, slightly diverge, or slightly converge, the light being input from the corresponding laser (8) or output to the corresponding photodiode (10), as the case may be. Each lens (24) can be optically aligned with a corresponding lens (14) of the second optical coupling device (3), such as described above in relation to other embodiments.

[0065] The combined structure of the substrate (1), encapsulate (22), and first optical coupling device (23) can be soldered to a larger PCB assembly via a standard reflow process. Similar to other embodiments described above, a planar bottom surface (17) of the second optical coupling device (3) is compressed against a corresponding planar top surface (17) of the first optical coupling device (23).

[0066] Figure 13 shows a side view of a sub-assembly of substrate (1), encapsulate (22), first optical coupling device (23), and second optical coupling device (3), according to these embodiments. As shown in Figure 13, the second optical coupling module may include a mounting surface (16) for respective optical fibers (12), with each groove in the mounting surface aligning with a corresponding one of the lenses (14) in the second optical coupling module.

[0067] As shown in Figure 10, the second optical coupling device (3) also includes a redirection optic (15, e.g., total internal reflector) that redirects light to / from the one or more optical fibers (12). In some embodiments, the redirection optic (15) may include an integrated coupling lens to focus light to the optical fiber(s) or collimate light from the optical fiber(s).

[0068] Similar to embodiments shown in Figures 1-4, the embodiments shown in Figures 8 and 10 include a cover (5) that compresses the corresponding surfaces (17) of the first optical coupling device (23) and the second optical coupling device (3). The compression force may be provided by a first part of a clip mechanism (11) on the cover (5) that mates with a corresponding second part of the clip mechanism (11) on the first optical coupling device (23). A package housing (6) may be assembled on the outside of the cover (5) and may substantially surround the cover (e.g., except for opening needed for ingress of optical fibers). The optical fibers (12) may be coupled to the package housing (20) by a mechanical strain relief (4) device.

[0069] In the embodiments shown in Figures 8-13, the alignment of the first and second optical coupling devices only requires the two corresponding surfaces (17) to be parallel. The horizontal placement of the first and second optical coupling devices is less critical such that standard mechanical guiding mechanisms can be used for alignment during assembly. In the embodiments shown in Figures 8-13, assembly can be performed with a solder reflow process and after assembly, the second optical coupling device can be physically connected with no precision alignment necessary. Moreover, the second optical coupling device can be physically connected and disconnected as needed.

[0070] The first optical coupling device (23) and second optical coupling device (3) shown in Figures 8-13 can operate according to the principles illustrated in Figure 5.

[0071] Figures 14-15 show different pre-assembly views of an OED (1400) according to other embodiments of the present disclosure. For example, the OED shown in Figures 14-15 can be a WDM optical transceiver with one or more optical fiber channels. Figure 16 shows a cross- sectional view of an assembly of the OED shown in Figures 14-15. The following description refers to these figures.

[0072] Substrate (25, also referred to as “Stratum- 1”) is a planar multi-layer PCB constructed of laminate dielectric, ceramic, or other materials such to provide a planar surface for mounting active optical devices such as vertically-emitting lasers (41) of different wavelengths and photodiodes (42) capable of receiving multi-wavelength light, as well as electronic devices (40, 43) that interface with and / or control the active optical devices. Substrate (25) also includes electrically conductive contacts (33) arranged to attach the substrate to a larger PCB assembly. The electrically conductive contacts are shown as balls in a Ball-Grid-Array (BGA), but may also be configured as a Pin-Grid- Array (PGA) or a Flat-No-Lead array. In these embodiments, a first optical coupling device (26) is physically attached to the substrate (25) with adhesive, welding, fusing, or any other technique that would provide secure attachment. The bottom surface of the first optical coupling device (26) may include a lens array (34) arranged to focus or collimate multi-wavelength light to or from, respectively, the active optical components on substrate (25).

[0073] According to the embodiments illustrated in Figure 16, the bottom surface of the first optical coupling device has a recessed area in which lens array (34) is located. Moreover, the bottom surface of the first optical coupling device is against the top surface of the substrate, such that the recessed area surrounds the active optical devices (41, 42) mounted to the substrate.

[0074] The first optical coupling device (26) can also include a receptacle or recess for a zig-zag WDM block (27), which is arranged to combine individual wavelengths into a multi-wavelength collimated beam or to separate a multi-wavelength collimated beam into individual wavelengths, depending on the direction of the light. A plurality of wavelength selective bandpass filters (35) are mounted to a bottom surface of WDM block (27). Each filter is configured to pass a different wavelength of a multi-wavelength collimated beam, i.e., as emitted by lasers (41) or as received by photodiodes (42) on the substrate (25). Each filter is also optically aligned with a corresponding lens of array (34).

[0075] A second optical coupling device (28) mounts to the first optical coupling device (26) such that the bottom surface (38b) of the second optical coupling device and the top surface (38a) of the first optical coupling device are parallel and against each other. Due to the receptacle for WDM block (27) on the top surface (38a) of the first optical coupling device (26), the entire bottom surface (38b) of the second optical coupling device (28) is not against the top surface of the second optical coupling device (28), as in other embodiments. Rather, the top of WDM block is exposed to a portion of the bottom surface (38b) of the second optical coupling device (28), such that the left-most of the optical bandpass filters (35) in Figure 16 is optically aligned with one or more lenses (36) molded into the bottom surface of the second optical coupling device (28).

[0076] Like other embodiments descried above, the second optical coupling device (28) also includes a redirection optic (37, e.g., total internal reflector) that redirects light between individual fibers of fiber array (32) and the one or more lenses (36) in the bottom surface of the second optical coupling device (28). Figure 17 shows top and side views of some embodiments of a sub-assembly of the substrate (25), the first optical coupling device (26), and the second optical coupling device (28) as shown in Figures 15-16. A layer of reflective material (52) is coated on or affixed to a top surface of WDM block (27). The reflective layer (52) is configured to reflect light from each optical filter towards an adjacent optical filter in a zig-zag optical path (54), as shown. The top surface of WDM block (27) also includes area (53, also referred to as “exit surface”) where the reflectivity layer (52) is absent such that the multi-wavelength light can exit to (or enter from) the second optical coupling device (28). Note that the area (53) is optically aligned with one of the filters (35).

[0077] The recess in the first optical coupling device (26) includes a mounting surface (56) for WDM block (27). The mounting surface is arranged at a non-zero angle relative to the planar top surface of the first optical coupling device (26). This non-zero angle can be selected to facilitate light entering from the second optical coupling device (28) to follow the zig-zag path (54) to strike the center of each optical filter (35) and the reflective layer (52). Note that the first optical coupling device (26) is mounted such that its bottom surface is against the top surface of the encapsulate (22) covering the components mounted on the substrate (25).

[0078] The first optical coupling device (26), the second optical coupling device (28), and the WDM block (27) can be molded separately and then assembled. For example, the WDM block (27) can be bonded to its mounting surface in the first optical coupling device (26), then the first optical coupling device (26) and the second optical coupling device (28) may be stacked sequentially on top of encapsulate (22) in the arrangement shown in Figure 17.

[0079] Figure 18 shows top and side views of other embodiments of a sub-assembly of the substrate, the first optical coupling device, and the second optical coupling device as shown in Figures 15-16. In these embodiments, the first optical coupling device (55) is arranged into two parts. The first (or bottom) part (57) has the lens array (34) recessed into its top surface and has a bottom surface that mounts to the encapsulate (22) top surface (e.g., both surfaces are planar). The second (or top) part (58) has a recessed area for holding WDM block (27), which may be identical to WDM block (27) discussed above in relation to other figures. The second pail (58) includes a mounting surface (56) arranged at a non-zero angle relative to the planar top surface of the first optical coupling device (55). Similar to the embodiments illustrated by Figure 17, this non-zero angle can be selected to facilitate light entering from the second optical coupling device (28) to follow the zig-zag path (54) to strike the center of each optical filter (35) and a reflective layer coated on or affixed to a top surface of WDM block (27).

[0080] The first (57) and second (58) parts of the first optical coupling device (55), the second optical coupling device (28), and the WDM block (27) can be molded separately and then assembled. For example, the WDM block (27) can be bonded to its mounting surface in the second part (58), then the first (57) and second (58) parts of the first optical coupling device (55) and the second optical coupling device (28) are stacked sequentially on top of encapsulate (22) in the arrangement shown in Figure 18.

[0081] Similar to other embodiments described above, the embodiments shown in Figures 14-16 include a cover (29) that compresses the corresponding surfaces (38) of the first optical coupling device (26, 55) and the second optical coupling device (28). The compression force may be provided by a first part of a clip mechanism (39) on the cover (29) that mates with a corresponding second part of the clip mechanism (39) on the first optical coupling device (26, 55). A package (or outer) housing (30) may be assembled on the outside of the cover (29) and may substantially surround the cover (e.g., except for opening needed for ingress of optical fibers). The optical fibers (32) may be coupled to the package housing (30) by a mechanical strain relief (31) device.

[0082] In the embodiments shown in Figures 14-16, the alignment of the first and second optical coupling devices only requires the two corresponding surfaces (38a, b) to be parallel. The horizontal placement of the first and second optical coupling devices is less critical such that standard mechanical guiding mechanisms can be used for alignment during assembly. In the embodiments shown in Figures 14-16, assembly can be performed with a solder reflow process and after assembly, the second optical coupling device can be physically connected with no precision alignment necessary. Moreover, the second optical coupling device can be physically connected and disconnected as needed.

[0083] The first optical coupling device (26, 55) and second optical coupling device (28) shown in Figures 14-18 can operate according to the principles illustrated in Figure 5.

[0084] In various embodiments described above, the lenses that focus light to the photodiodes or collimate light from the lasers are in the first optical coupler. In contrast, Figure 19 shows a substrate (62) carrying laser and photodiode components with integrated lenses, according to some embodiments of the present disclosure. In particular, a collimating lens (47a) is integrated into the backside of each vertically-emitting laser (47) and a focusing lens (48a) is integrated into the backside of each vertically-receiving photodiode (48). The other sides of laser (47) and photodiode (48) arc mounted to a substrate (44), along with electronic components (45, 46) that interface with and / or control laser (47) and photodiode (48). The thickness of substrates in the laser and the photodiode defines the focal length of the integrated lens. For example, the laser (47) can be a vertical cavity surface emitting laser (VCSEL), which can be flip-chip mounted to the substrate.

[0085] When embodiments shown in Figure 19 are used in an OED, the first optical coupling device (e.g., 2) mounted to the primary substrate (e.g., 1) only needs to have a planar top surface (e.g., 17) to mate with a corresponding planar bottom surface (e.g., 17) of the second optical coupling device (e.g., 3). The embodiments illustrated by Figure 19 can simplify assembly because minimal alignment is needed for attachment of the first optical coupling device to the substrate, since the lenses are integrated directly into the optoelectronics components.

[0086] In various embodiments described above, the lenses that focus light to the photodiodes or collimate light from the lasers are located in the first optical coupler. In contrast, Figure 20 shows a substrate with laser, photodiode, and lens components, according to other embodiments of the present disclosure. In particular, the one or more lasers (61) and the one or more photodiodes (60) are mounted on an optically transparent substrate (62) that includes integrated collimating lenses (63, 64). This substrate also includes electrically conductive contacts (59) arranged to connect the substrate to a primary substrate (e.g., 1), which can then be attached to a larger PCB assembly in the manner described above in relation to other embodiments. The electrically conductive contacts (59) are shown as balls in a BGA, but may also be configured as a PGA or a Flat-No-Lead array.

[0087] For example, the substrate can be a semiconductor material, and the lenses (64) can be integrated into the semiconductor material using standard semiconductor processes. As a more specific example, a Gallium Arsenide (GaAs) substrate will survive reflow soldering and is transparent to light at wavelengths of interest. The lasers (e.g., VCSELs) and photodiodes can be bonded to the non-lens side of the semiconductor substrate, which can have alignment marks to facilitate placement of these components in optical alignment with the integrated lenses. The lasers can be backside emitting or flip-chip attached to the substrate.

[0088] When embodiments shown in Figure 20 are used in an OED, the first optical coupling device (e.g., 2) mounted to the primary substrate (e.g., 1) only needs to have a planar top surface (e.g., 17) to mate to a corresponding planar bottom surface (e.g., 17) of the second optical coupling device (e.g., 3). The embodiments illustrated by Figure 20 can simplify assembly because alignment is only needed for attachment of the substrate shown in Figure 20 to the primary substrate.

[0089] Figure 21 shows a side view of other embodiments of a sub-assembly comprising a substrate (25), a first optical coupling device (65), and a second optical coupling device (66). For example, the sub-assembly shown in Figure 21 can be used in various OEDs shown in other figures described above.

[0090] The substrate (25) may be similar to substrates described above in relation to other embodiments. For example, there may be an encapsulate (22) covering active optical and / or electronic components mounted on the substrate (25). The top surface of the first optical coupling device (65) includes a recessed area (or recess) in which a lens array (34) is located. This lens array is arranged to focus or collimate multi-wavelength light to or from, respectively, the active optical components on substrate (25).

[0091] The top surface of the second optical coupling device (66) may include a receptacle or recess, which may include a mounting surface (68) for a zig-zag WDM block (27). This component may be similar to zig-zag WDM blocks described above in relation to other embodiments. A plurality of wavelength selective bandpass filters (35) are mounted to a bottom surface of WDM block (27), and may have similar functionality as wavelength selective bandpass filters described above in relation to other embodiments.

[0092] The mounting surface (68) may have a further recess to accommodate the plurality of wavelength selective bandpass filters (35) on the bottom surface of WDM block (27). Additionally, the mounting surface (68) may include one or more lenses (69) molded therein. The second optical coupling device (66) also includes a redirection optic (67, e.g., total internal reflector) that redirects light between individual fibers of fiber array (32) through the one or more lenses (69) in the mounting surface (68) and into the WDM block (27). Each lens (69) may be configured to collimate or focus the light incident from a corresponding fiber (32).

[0093] The mounting surface (68) is arranged at a non-zero angle relative to the planar top surface of the second optical coupling device (66). This non-zero angle can be selected to facilitate light entering from the one or more lenses (68) to follow zig-zag path (54) to strike the center of each wavelength selective bandpass filter (35) and a layer of reflective material (52) coated on or affixed to a top surface of WDM block (27). The reflective layer (52) is configured to reflect light from each wavelength selective bandpass filter towards an adjacent filter in a zig-zag optical path, similar to other embodiments discussed above. In contrast to other embodiments, however, reflective layer (52) may cover the entire top surface of WDM block (27).

[0094] Due to the recess in the top surface of the first optical coupling device (65), the entire bottom surface of the second optical coupling device (66) is not against the top surface of the first optical coupling device (65), as in other embodiments. Rather, the top of lens array (34) is exposed to a portion of the bottom surface of the second optical coupling device (66), such that each of the wavelength selective bandpass filters (35) is optically aligned with a corresponding one of the lenses of lens array (34).

[0095] In the arrangement shown in Figure 21, the first optical coupling device (65), the second optical coupling device (66), and the WDM block (27) can be molded separately and then assembled. For example, the WDM block (27) may be bonded to its mounting surface (68) in the second optical coupling device (66), then the first optical coupling device (65) and the second optical coupling device (66) stacked sequentially on top of encapsulate (22) in the arrangement shown in Figure 21.

[0096] Figure 22 shows a variant of the sub-assembly shown in Figure 21. In this variant, the one or more lenses (69) are integrated with the redirection optic (67) rather than in the mounting surface for the WDM block (27).

[0097] Note that in Figures 21-22, the lens array (34) may be two- dimensional like the corresponding lens array shown in Figure 18. For example, the lens array (34) can have a dimension n x m, with n representing the number of different wavelengths in each fiber (32) and m representing the number or fibers. In general, m can be one or greater than one.

[0098] Various embodiments described above can be used with different fiber configurations, including single fiber, dual fibers, multiple (>2) fibers, ribbon fiber, etc. In various embodiments, the lenses can be constructed from different materials such as plastic (e.g., Ultem), encapsulant epoxy, glass, or other suitable optical lens material.

[0099] In some embodiments, the cover or housing can be constructed fully or partially of a thermally conductive metal, particularly pails that contact the substrate. This can improve dissipation of heat generated by the components mounted on the substrate.

[0100] In some embodiments, one or more gaskets can be used between different components stacked on top of the substrate for improved environmental sealing. In some embodiments, a switch or other mechanical feature can be used to ensure that the cover and / or housing is installed before the lascr(s) can be turned on.

[0101] In some embodiments, one set of lenses, on either the first optical coupling device or the second optical coupling device, may include a small, angled offset from parallel to reduce back reflections into the laser cavity. This can mitigate performance degradation due to optical back reflections into the aperture of the laser.

[0102] Figure 23 shows an exemplary method for assembling an OED, such as various OEDs described above in relation to Figures 1-18 and 21-22.

[0103] Operation 2310 may include initially assembling the substrate with all active components such as lasers and photodiodes. Operation 2330 may include attaching the bottom surface of the second optical coupling device to the top surface of the first optical coupling device so that the lenses in the two devices are optically aligned. For example, this may be done using a mechanical compression device (e.g., latch, clip, etc.).

[0104] Subsequently, operation 2340 may include attaching a bottom surface of the first optical coupling device to a top surface of the substrate (or encapsulate thereof), so the lenses in first optical coupling device are optically aligned with the lasers and / or photodiodes on the substrate. For example, the bottom surface of the first optical coupling device may be permanently attached to the substrate (or encapsulate thereof) by adhesive or other appropriate attachment mechanism.

[0105] Subsequently, operation 2350 may include removing the bottom surface of the second optical coupling device from the top surface of the first optical coupling device, such as by removing a mechanical compression device that holds together the corresponding planar surfaces. In operation 2360, the substrate and attached first optical coupling device may be passed through reflow soldering to attach electrical contacts on a bottom surface of the substrate to a PCB. In operation 2370, after the reflow soldering, the bottom surface of the second optical coupling device may be reattached to top surface of the first optical coupling device, thereby forming a subassembly.

[0106] Operation 2380 may include installing a cover that compresses the bottom surface of the second optical coupling device against the top surface of the first optical coupling device and the bottom surface of the first optical coupling device against the top surface of the substrate, such as illustrated in various figures described above. For example, the cover may include a first pail of a clip mechanism and the first optical coupling device may include a second part of the clip mechanism that mates with the first part when the cover is installed. In addition, possibly other mechanical components (c.g., housing, strain relief, etc.) may be installed and the fibcr(s) may be combined with the sub-assembly into a final assembly, such as illustrated in various figures described above.

[0107] In some embodiments, prior to operation 2330, operation 2320 may be performed including mounting the bottom surface of a WDM optic to a mounting surface in a recess in the top surface of the first or second optical coupling device, such as illustrated in various figures described above.

[0108] In some of these embodiments, the first optical coupling device includes a first pail and a second part, such as shown in Figure 18 described above. In such embodiments, the bottom surface of the second optical coupling device is attached to (operation 2330), removed from (operation 2350), and reattached to (operation 2370) a top surface of the second part. In such embodiments, operation 2325 may be performed prior to operation 2330, including attaching a bottom surface of the second part to a top surface of the first part.

[0109] The foregoing merely illustrates the principles of the disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and procedures that, although not explicitly shown or described herein, embody the principles of the disclosure and can be thus within the spirit and scope of the disclosure. Various embodiments can be used together with one another, as well as interchangeably therewith, as should be understood by those having ordinary skill in the art.

[0110] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the ail to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0111] In addition, certain terms used in the present disclosure, including the specification and drawings, can be used synonymously in certain instances (e.g., “data” and “information”). It should be understood, that although these terms (and / or other terms that can be synonymous to one another) can be used synonymously herein, there can be instances when such words can be intended to not be used synonymously. Example embodiments of the techniques and apparatus described herein include, but are not limited to, the following enumerated embodiments:

[0112] Embodiment Al. An opto-electronic device (OED) comprising:

[0113] • a substrate having mounted thereon one or more active optical devices, wherein the substrate includes a bottom surface having a plurality of electrically conductive contacts configured for attachment to a printed circuity board (PCB) assembly via a reflow soldering process;

[0114] • a first optical coupling device located above a top surface of the substrate, wherein the first optical coupling device includes a planar top surface;

[0115] • one or more first lenses that are optically aligned with the respective one or more active optical devices mounted on the substrate; and

[0116] • a second optical coupling device comprising a planar bottom surface, one or more second lenses, and receptacles for one or more optical fibers, wherein: o the one or more second lenses are optically aligned with the respective receptacles, and o the bottom surface is against the top surface of the first optical coupling device such that the one or more second lenses are optically aligned with the respective one or more first lenses.

[0117] Embodiment Ala. The OED of embodiment Al, wherein the one or more first lenses arc attached to or integrated into the planar top surface of the first optical coupling device or a bottom surface of the first optical coupling device (see, e.g., Figures 3-4, 7, 10, 12-13, 16-18) .

[0118] Embodiment Alb. The OED of embodiment Al, wherein the one or more first lenses are attached to or integrated into top surfaces of the respective active optical devices, with the bottom surfaces of the respective active optical devices being mounted to the substrate (see, e.g., Figure 19).

[0119] Embodiment Ale. The OED of embodiment Al, wherein the one or more first lenses are attached to or integrated into a first side of a second optically transparent substrate, the one or more active optical devices are attached to a second side of the second optically transparent substrate, and the second side of the second optically transparent substrate includes a second plurality of electrically conductive contacts that arc attached to the substrate (sec, c.g., Figure 20).

[0120] Embodiment A2. The OED of any of embodiments Al-Alc, wherein the second optical coupling device includes a redirection optic located in an optical path between the one or more second lenses and the one or more receptacles (see, e.g., Figures 3, 10, 16-18).

[0121] Embodiment A3. The OED of any of embodiments A1-A2, wherein the OED also includes a cover that, when installed, compresses the bottom surface of the second optical coupling device against the top surface of the first optical coupling device (see, e.g., Figures 1-3, 6-8, 10, 14, 16).

[0122] Embodiment A4. The OED of any of embodiments A1-A3, wherein:

[0123] • the one or more first lenses collimate light from the one or more active optical devices and focus light to the one or more active optical devices; and

[0124] • the one or more second lenses collimate light from optical fibers in the one or more receptacles and focus light to optical fibers in the one or more receptacles (see, e.g., Figure 5).

[0125] Embodiment AS. The OED of any of embodiments A1-A4, wherein:

[0126] • the one or more active optical devices are mounted on a top surface of the substrate;

[0127] • the first optical coupling device includes a bottom surface with a recessed area; and

[0128] • the bottom surface of the first optical coupling device is against the top surface of the substrate, such that the recessed area covers the one or more active optical devices (see, e.g., Figures 3, 7).

[0129] Embodiment A6. The OED of any of embodiments A1-A4, wherein:

[0130] • the one or more active optical devices are mounted on a top surface of the substrate;

[0131] • the OED also includes an optically transparent encapsulate with a planar top surface and a bottom surface that covers at least the one or more active optical devices; and

[0132] • the bottom surface of the first optical coupling device is planar and is against the planar top surface of the encapsulate (see, e.g., Figures 8-13). Embodiment A7. The OED of any of embodiments A1-A4, wherein:

[0133] • the OED also includes a wavelength division multiplexing (WDM) optic that includes a bottom surface with a plurality of wavelength-selective filters mounted thereto and a top surface with a reflective coating;

[0134] • a top surface of the second optical coupling device includes a recess; and

[0135] • the WDM optic is mounted in the recess such that the wavelength-selective filters are optically aligned with respective ones of the first lenses and one of the wavelength- selective filters is optically aligned with one of the second lenses (see, e.g., Figures 14-18).

Claims

AMENDED CLAIMS received by the International Bureau on 04 April 2025 (04.04.2025)1. An opto-electronic device, OED (100, 600, 800, 1400) comprising: a substrate (1, 25) having mounted thereon one or more active optical devices (8, 10, 41, 42, 60, 61), wherein the substrate includes a bottom surface having a plurality of electrically conductive contacts (9, 33) configured for attachment to a printed circuit board, PCB, assembly via a reflow soldering process; a first optical coupling device (2, 23, 26, 55, 65) located above a top surface of the substrate, wherein the first optical coupling device comprises a top surface (17a, 38a); one or more first lenses (13, 24, 34, 47a, 48a, 63, 64) that are optically aligned with the respective one or more active optical devices mounted on the substrate; and a second optical coupling device (3, 18, 28, 66) comprising a bottom surface (17b, 38b) and one or more second lenses (14, 21, 36, 69), wherein the bottom surface (17b, 38b) of the second optical coupling device is arranged against the top surface (17a, 38a) of the first optical coupling device such that the one or more second lenses (14, 21, 36, 69) are optically aligned with the respective one or more first lenses (13, 24, 34, 47a, 48a, 63, 64), wherein the OED is arranged such that the bottom surface (17b, 38b) of the second optical coupling device is attachable to the top surface (17a, 38a) of the first optical coupling device after the attachment of the plurality of electrically conductive contacts (9, 33) to the PCB assembly via the reflow soldering process.

2. The OED of claim 1 , wherein the bottom surface of the second optical coupling device and the top surface of the first optical coupling device are co-planar.

3. The OED of any of claims 1-2, wherein the one or more first lenses (24) are attached to or integrated into the top surface (17a, 38a) of the first optical coupling device (800).

4. The OED of any of claims 1-2, wherein the one or more first lenses (13, 34) are attached to or integrated into a bottom surface of the first optical coupling device (100, 600, 1400).

5. The OED of any of claims 1-2, wherein: the first optical coupling device (55) comprises a first part (57) and a second part (58); a bottom surface of the second part is arranged against a top surface of the first part; and the top surface of the first part includes a recess in which the one or more first lenses (34) are located.

6. The OED of any of claims 1-2, wherein: the one or more first lenses (47a, 48a) are attached to or integrated into top surfaces of the respective active optical devices (47, 48); and bottom surfaces of the respective active optical devices are mounted to the substrate.

7. The OED of any of claims 1-2, wherein: the one or more first lenses (63, 64) are attached to or integrated into a first side of a second optically transparent substrate (62); the one or more active optical devices (60, 61) are attached to a second side of the second optically transparent substrate; and the second side of the second optically transparent substrate includes a second plurality of electrically conductive contacts (59) that are attached to the substrate.

8. The OED of any of claims 1-7, wherein the second optical coupling device (3, 28) further comprises receptacles (16) for one or more optical fibers (12, 32), and the one or more second lenses (14, 21, 36, 69) are optically aligned with the respective receptacles (16).

9. The OED of claim 8, wherein the second optical coupling device includes a redirection optic (15, 37, 67) arranged in an optical path between the one or more second lenses (14, 36, 69) and the one or more receptacles (16).

10. The method of claim 9, wherein the one or more second lenses (14, 36, 69) are integrated into the redirection optic (67).

11. The OED of any of claims 8-10, wherein: the one or more first lenses collimate light from the one or more active optical devices and focus light to the one or more active optical devices; and the one or more second lenses collimate light from optical fibers in the one or more receptacles and focus light to optical fibers in the one or more receptacles.

12. The OED of any of claims 1-11, further comprising a cover (5, 19, 29) that, when installed, compresses the bottom surface (17b, 38b) of the second optical coupling device against the top surface (17a, 38a) of the first optical coupling device.

13. The OED of claim 12, wherein the cover includes a first part of a clip mechanism (11, 39) and the first optical coupling device includes a second part of the clip mechanism (11, 39) that mates with the first part when the cover is installed.

14. The OED of any of claims 12-13, further comprising: an outer housing (6, 20, 30) that substantially surrounds the cover (5, 19, 29); and a mechanical strain relief device (4, 31) coupled to the outer housing and arranged to accept the one or more optical fibers (12).

15. The OED of any of claims 1-14, wherein the one or more active optical devices (8, 10, 41, 42) are mounted on a top surface of the substrate.

16. The OED of claim 15, wherein: the first optical coupling device (2, 26) includes a bottom surface with a recess; and the bottom surface of the first optical coupling device is arranged against the top surface of the substrate, such that the recess in the bottom surface surrounds the one or more active optical devices.

17. The OED of claim 15, wherein: the OED (800) also includes an optically transparent encapsulate (22) that surrounds at least the one or more active optical devices on the top surface of the substrate; anda bottom surface of the first optical coupling device is planar and is arranged against a planar top surface of the encapsulate.

18. The OED of claim 17, further comprising a cover (5, 19, 29) that, when installed, compresses the following: the bottom surface of the second optical coupling device against the top surface of the first optical coupling device, and the bottom surface of the first optical coupling device against the top surface of the substrate.

19. The OED of any of claims 1-18, wherein the OED (1400) also includes a wavelength division multiplexing, WDM, optic (27) having a bottom surface with a plurality of wavelength- selective filters (35) mounted thereto and a top surface with a reflective coating (52) arranged to reflect light incident from the plurality of wavelength-selective filters.

20. The OED of claim 19, wherein one of the following includes a recess in which the WDM optic is mounted: the top surface of the first optical coupling device (26), or a top surface of the second optical coupling device (66).

21. The OED of claim 20, wherein the WDM optic is mounted in the recess such that: the plurality of wavelength-selective filters are optically aligned with respective ones of the first lenses; and a first one of the plurality of wavelength-selective filters is optically aligned with a particular one of the second lenses.

22. The OED of claim 21, wherein the reflective coating is absent from an area of the WDM optic’s top surface that is optically aligned with the first wavelength-selective filter and the particular second lens.

23. The OED of any of claims 20-22, wherein the recess includes a mounting surface (56, 68) on which the WDM optic is mounted, with the mounting surface being arranged at a non-zero angle relative to the top surface in which the recess is included.

24. The OED of claim 23, wherein the recess is in the top surface of the second optical coupling device (66) and the one or more second lenses (69) are integrated into the mounting surface (68) in the recess.

25. The OED of any of claims 20-24, wherein: the first optical coupling device (55) comprises a first part (57) and a second part (58); a bottom surface of the second part is arranged against a top surface of the first part; and the top surface of the second part includes the recess in which the WDM optic is mounted.

26. A method for assembling an opto-electronic device, OED (100, 600, 800, 1400) that includes a substrate (1, 25), a first optical coupling device (2, 23, 26, 55, 65), one or more first lenses (13, 24, 34, 47a, 48a, 63, 64), and a second optical coupling device (3, 18, 28, 66), the method comprising: attaching (2330) a bottom surface (17b, 38b) of the second optical coupling device to a top surface (17a, 38a) of the first optical coupling device, such that the one or more second lenses (14, 21, 36, 69) of the second optical coupling device are optically aligned with the respective one or more first lenses (13, 24, 34, 47a, 48a, 63, 64); subsequently attaching (2340) a bottom surface of the first optical coupling device to a top surface of the substrate, such that the one or more first lenses are optically aligned with respective one or more active optical devices (8, 10, 41, 42, 60, 61) mounted to the substrate; subsequently removing (2350) the bottom surface of the second optical coupling device from the top surface of the first optical coupling device; subsequently attaching (2360) a plurality of electrically conductive contacts (9, 33) on a bottom surface of the substrate to a printed circuit board, PCB, using a reflow soldering process; and subsequently reattaching (2370) the bottom surface of the second optical coupling device to the top surface of the first optical coupling device, such that the one or moresecond lenses are optically aligned with the respective one or more first lenses and the respective one or more active optical devices.

27. The method of claim 26, further comprising installing (2380) a cover (5, 19, 29) that compresses the following: the bottom surface of the second optical coupling device against the top surface of the first optical coupling device, and the bottom surface of the first optical coupling device against the top surface of the substrate.

28. The method of claim 27, wherein the cover includes a first part of a clip mechanism (11, 39) and the first optical coupling device includes a second part of the clip mechanism (11, 39) that mates with the first part when the cover is installed.

29. The method of any of claims 26-28, wherein: the OED (1400) also includes a wavelength division multiplexing, WDM, optic (27) having a bottom surface with a plurality of wavelength-selective filters (35) mounted thereto; one of the following includes a recess: a top surface of the first optical coupling device (26), or a top surface of the second optical coupling device (66); and the method further comprises mounting (2320) the bottom surface of the WDM optic to a mounting surface (56, 68) of the recess, prior to attaching (2330) the bottom surface of the second optical coupling device to the top surface of the first optical coupling device.

30. The method of claim 29, wherein the bottom surface of the WDM optic is mounted in the recess such that: the plurality of wavelength-selective filters are optically aligned with respective ones of the first lenses; and a first one of the plurality of wavelength-selective filters is optically aligned with a particular one of the second lenses.

31. The method of any of claims 29-30, wherein the mounting surface of the recess is arranged at a non-zero angle relative to the top surface in which the recess is included.

32. The method of any of claims 29-31, wherein: the first optical coupling device (55) comprises a first part (57) and a second part (58); the bottom surface of the second optical coupling device is attached to, removed from, and reattached to a top surface of the second part; the method further comprises attaching (2325) a bottom surface of the second part to a top surface of the first part, prior to attaching the bottom surface of the second optical coupling device to the top surface of the first part; and the top surface of the second part includes the recess in which the WDM optic is mounted.

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