Alignment structures and methods for co-packaging optical connectors

Abstract

The invention relates to an alignment structure and method for co-packaging optical connectors. An apparatus for aligning a fiber array unit (FAU) connector with a photonic integrated circuit (PIC) includes an aligner having a front section and a bottom section, the front section and the bottom section being bonded with two side sections spaced apart by a first distance, respectively. The front section and the bottom section are partially removed to enlarge a semi-closed open space between the two side sections for receiving a shelf of a lens extending beyond a side edge of the PIC chip. The shelf has an alignment feature associated with the lens. The front section is configured as a support bar positioned on a surface of the PIC chip. The semi-closed open space between the two side sections allows a body of the FAU connector to be loaded from top down to lie on the shelf in the semi-closed open space and aligned with the lens by the alignment feature.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Patent Application No. 63 / 600,151, filed on November 17, 2023, which is jointly assigned and incorporated herein by reference in its entirety for all purposes. Technical Field

[0003] This technology relates to devices and methods for aligning optical connectors with co-packaged optical systems. Background Art

[0004] As data rates increase in optical communication systems, there is a strong trend to move the high-speed electrical signals of transceivers closer to switching modules. This has led to the development and implementation of so-called co-packaged optics (CPO) systems by mounting transceiver optics next to silicon-based channel switches. With technological advancements, these co-packaged optics need to be miniaturized through the application of silicon photonics integrated circuit (SPIC) technology. SPICs require optical inputs and outputs. The input on the transmitter side is continuous-wave (CW) light, which is then modulated and sent into the output. The input on the receiver side is modulated light, which is then converted into an electrical signal.

[0005] Existing techniques for inputting and receiving light from silicon photonics integrated circuits actively align fiber blocks by pigtailing and glue them in place using epoxy. The problem with pigtailed fiber cables is that the structure can become very bulky and difficult to manage, especially for CPOs with switching chips, which may have hundreds of optical fibers for input / output. Also, CPO switch ICs typically need to be attached to another substrate via ball grid array (BGA) technology, which requires the structure to undergo solder reflow at high temperatures, which may damage the fiber cable coating. Co-packaged optical systems should have a novel structural support where micro-optical connectors are safely placed on the inputs and outputs of SPICs, such as application-specific integrated circuits for switches on a photonic integrated circuit (PIC) chip, which is the subject addressed in this disclosure. Summary of the Invention

[0006] In one aspect, the present disclosure relates to an alignment structure for an optical component, comprising: an aligner including a plurality of sections joined together to provide a semi-closed open space configured to allow a body of a first optical component to be loaded into an alignment position to align with a second optical component. The plurality of sections include: a bottom section having a front edge facing a part of the semi-closed open space for receiving a shelf extending out of the second optical component; a pair of side sections respectively joined to the bottom section and separating a first width of the semi-closed open space to allow the body of the first optical component to be lowered from the top; and a front section joined to the pair of side sections, the front section configured to be a support bar positioned on a surface of the second optical component while the shelf and a part of the second optical component are inserted under the support bar in the semi-closed open space, and the shelf is used to support the body of the first optical component in the alignment position.

[0007] In another aspect, the present disclosure relates to an apparatus for aligning a fiber array unit (FAU) connector with a photonic integrated circuit (PIC), comprising: an aligner having a front section, a rear section, and a bottom section respectively joined to two side sections spaced apart by a first distance. The front section and the bottom section are configured to expand a semi-closed open space between the two side sections for receiving a shelf extending beyond a lens at a side edge of the PIC chip. The shelf has alignment features associated with the lens. The front section is configured to be a support bar positioned on a surface of the PIC chip. The semi-closed open space between the two side sections allows the body of the FAU connector to be loaded downward from the top to be located on the shelf in the semi-closed open space and to be aligned with the lens through the alignment features.

[0008] In another aspect, the present disclosure relates to a method for aligning a fiber optic array unit (FAU) connector with a photonic integrated circuit (PIC), which includes: attaching a frame to a package structure of the PIC chip to provide a support surface in a floating state, one of the support surfaces being configured to be bonded to a pair of shelves by epoxy resin, each shelf having alignment features respectively associated with two lenses of the PIC chip; placing a pair of aligners on the frame, each aligner including a front section and a bottom section respectively combined with two side sections spaced apart by a first distance to provide a semi-closed open space, the semi-closed open space being configured to receive one of the pair of shelves as the front section positioned on the top surface of the PIC chip, one of the support surfaces of the frame being configured to be bonded to the bottom section of each aligner by epoxy resin; loading a pair of bodies of two FAU connectors respectively onto the pair of shelves in the semi-closed open spaces of the pair of aligners, each body having a small degree of horizontal rotational freedom in the corresponding semi-closed open space and a translational freedom along a direction parallel to the two side sections; adjusting each body of the FAU connector to an alignment position on the corresponding shelf via the alignment features to achieve optical alignment between the lens of the FAU connector and one of the two lenses of the PIC chip; curing the epoxy resin between each shelf and the corresponding one of the support surfaces to fix the shelf and the body of the FAU connector at the alignment position; and curing the epoxy resin between each aligner and the corresponding one of the support surfaces of the frame to fix the position of the aligner to ensure a non-contact gap between the body of the FAU connector and the aligner. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A further understanding of the nature and advantages of particular embodiments may be realized by reference to the remaining portions of the specification and the drawings, wherein like reference numerals are used to refer to like components. In some instances, sub-labels are associated with the reference numerals to denote one of a plurality of like components. When a reference numeral is cited without specifying an existing sub-label, it is intended to refer to all such plurality of like components.

[0010] Figure 1 is a perspective top view of a co-packaged optical device photonic integrated circuit (CPO PIC) assembly having a plurality of fiber optic array unit (FAU) connectors for optical input / output (IO) in accordance with an embodiment of the present technology.

[0011] Figure 2 is a perspective view, a top view, and a side view of an aligner for aligning an FAU connector with a PIC chip in accordance with an embodiment of the present technology.

[0012] Figure 3 Perspective view of both the top and bottom of the body of an FAU connector with alignment rods, according to an embodiment of the present technology.

[0013] Figure 4 Configuration according to an embodiment of the present technology in which an aligner is placed in a frame to receive a shelf extending from a PIC chip in a semi - enclosed open space, and a perspective view of the same configuration with an FAU connector loaded on the shelf, beside said configuration.

[0014] Figure 5 Cross - sectional view showing a configuration according to an embodiment of the present technology in which the body of the FAU connector is guided downward to the shelf via an aligner, and a side configuration in which the body of the FAU connector is in an aligned position and the alignment rod mates with a V - shaped groove in the shelf in the lower aligner.

[0015] Figure 6 Top - view showing the loading position of the body of the FAU connector in a semi - enclosed open space, according to an embodiment of the present technology, with hard stops at the front and rear, degrees of rotational freedom and translational freedom to facilitate alignment with the shelf.

[0016] Figure 7 Perspective view showing the bodies of four (two pairs) FAU connectors loaded onto a shelf in a semi - enclosed open space provided by corresponding aligners supported by two (one pair) frames, with the flap in the open position, according to an embodiment of the present technology.

[0017] Figure 8 Perspective view of the bodies of four (two pairs) FAU connectors on the corresponding shelves with the flap in the closed position, according to an embodiment of the present technology.

[0018] Figure 9 Flowchart showing a method for aligning an FAU connector with a PIC chip, according to another embodiment of the present technology. Detailed Description

[0019] The present disclosure provides an alignment structure for an optical component. The structure includes an aligner having a plurality of sections joined together to provide a semi-closed open space configured to allow a body of a first optical component to be inserted into an alignment position to align with a second optical component. The plurality of sections includes a bottom section, a pair of side sections respectively joined to the bottom section, and a front section joined to the pair of side sections. A portion of the bottom section is removed to be part of the semi-closed open space for receiving a shelf extending out of the second optical component. The pair of side sections separate a first width of the semi-closed open space to allow loading of the body of the first optical component from the top. The front section is configured as a support bar positioned on a surface of the second optical component while the shelf and a portion of the second optical component are inserted under the support bar in the semi-closed open space to support the body of the first optical component in the alignment position. There are additional embodiments.

[0020] In an embodiment, the present technology relates to a solution for providing a support alignment structure for an operator to insert a micro fiber array unit (FAU) connector and fix it to a co-packaged optical device (CPO)-photonic integrated circuit (PIC) assembly. Figure 1 A perspective top view of a CPO-PIC assembly (10) with up to 16 FAU connectors (14) having optical input / outputs at four side edges of a PIC chip according to an embodiment of the present technology is shown. The package of the CPO-PIC assembly (10) includes a lid structure (12) fixed on a substrate, with a switch module (11) attached in the center, and optical input / output (IO) ports configured at corresponding four sides (indicated by dashed line 17) of the PIC chip. The lid structure (12) is configured to place an alignment structure (100) to allow each of the 16 FAU connectors (14) to be positioned at each edge of a corresponding side (17) of the PIC chip (not visible under the lid structure (12)) to establish optical coupling with the IO ports of the CPO-PIC assembly (10). The FAU connector (14) includes a small body followed by a ribbon fiber (15). The FAU connector body (14) is made of glass, semi-transparent, quite fragile, and very difficult to handle and position to achieve a firm alignment with the PIC chip. The alignment structure (100) is provided as a solid part for the optical connectors of the CPO-PIC assembly (10). Specifically, the alignment structure (100) enables an operator to (e.g., by hand) place the body of the FAU connector into a certain position to establish a micro-level alignment between a lens at the front end of the body of the FAU connector and a lens associated with the IO port of the PIC chip. The PIC chip is also very small in size and fragile. In an embodiment, the PIC chip has a shelf (13) extending out of each IO port at the side edge of the PIC chip. The shelf (13) contains alignment features (fromFigure 1 (not visible), the alignment features are configured to assist in aligning the lens at the front end of the body of the FAU connector with the lens associated with the IO port of the PIC chip. The alignment structure (100) is configured to provide a cutout space to fit within the shelf (13) to allow the body of the FAU connector (14) to be attached to the shelf and fixed in the aligned position using the alignment features on the shelf (13).

[0021] The optical connector for the CPO-PIC assembly (10) also includes other parts for supporting the alignment structure (100). In an embodiment, the alignment structure (100) is configured to rest partially on the surface of the PIC chip and be partially supported by the bottom surface of the frame structure (200), which is attached to the cover structure (12) in a floating state. "Floating state" is referred to herein as the physical state of the frame structure relative to its environment, which provides a partial attachment at the side of the frame structure without any direct bottom support. The frame structure (200) also provides a bottom surface for supporting the shelf (13) in a floating state. A CPO-PIC assembly having multiple FAU connectors assisted by the alignment structure (100) must undergo numerous quality tests, including shock and vibration, unbiased damp heat, and fiber optic tensile tests. In all of these tests, the alignment structure (100) provided by the present technology is configured to use a flip-up structure (300), which is coupled to the frame structure (200) via a pivot pin to open or close, to apply a force from the top to fix the body of the FAU connector to stay in the aligned position relative to the PIC chip and have a minimum change in optical input / output power.

[0022] The following description is presented to enable a person having ordinary skill in the art to make and use the invention and incorporate it into a particular application context. Various modifications and multiple uses in different applications will be apparent to those skilled in the art, and the general principles defined herein can be applied to a wide range of embodiments. Therefore, the invention is not intended to be limited to the embodiments presented, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0023] In the following detailed description, numerous specific details are set forth to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without being limited to these specific details. In other instances, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the invention.

[0024] The reader should note all papers and documents that are submitted together with and published with this specification for public inspection, and the contents of all such papers and documents are incorporated herein by reference. All features disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each disclosed feature is only an example of a series of general equivalent or similar features.

[0025] In addition, any element in a claim that does not expressly state a "means" for performing a specified function or a "step" for performing a particular function should not be construed as a "means" or "step" clause as specified in paragraph 6 of 35 U.S.C. § 112. In particular, the use of "step of..." or "act of..." in the claims herein is not intended to invoke the provisions of 35 U.S.C. § 112, paragraph 6.

[0026] When an element is referred to herein as being "connected" or "coupled" to another element, it should be understood that the element can be directly connected to the other element or have intervening elements therebetween. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, it should be understood that there are no intervening elements in the "direct" connection between the elements. However, the existence of a direct connection does not exclude other connections in which intervening elements may be present.

[0027] When an element is referred to herein as being "disposed" relative to another element in a certain manner (e.g., disposed on it, disposed between them, disposed under it, disposed adjacent to it, or disposed in some other relative manner), it should be understood that the element can be directly disposed relative to the other element (e.g., directly disposed on another element) or have intervening elements therebetween. In contrast, when an element is referred to as being "directly disposed" relative to another element, it should be understood that there are no intervening elements in the "direct" instance. However, the existence of a direct disposition does not exclude other instances in which intervening elements may be present.

[0028] Similarly, when an element is referred to herein as being "joined" to another element, it is understood that the element can be joined directly to the other element (without any intervening element) or have intervening elements present between the joined elements. In contrast, when an element is referred to as being "directly joined" to another element, it is understood that there are no intervening elements in the "direct" joining between the elements. However, the presence of a direct joining does not exclude other forms of joining in which intervening elements may be present. When a section or part of a single solid structure is referred to herein as being "joined" to another section or part of the same structure, it is understood that the section or part can be an integral part of the single solid structure that is specifically designated for some unique function as compared to other sections or parts. The single solid structure can be machined or cast or 3D printed as a whole piece. Alternatively, all sections or parts of the solid structure can be made individually (machined, cast, or printed), but optionally joined together as a single structure by welding, brazing, mechanical fastening, adhesive bonding, press fitting, thermal joining, or chemical joining. The present technology focuses on their individual or overall function as a solid structure and should be applicable to any manufacturing method.

[0029] Likewise, when an element is referred to herein as a "layer", it is understood that the layer can be a single layer or include multiple layers. For example, a conductive layer can include a variety of different conductive materials or multiple layers of different conductive materials, and a dielectric layer can include a variety of dielectric materials or multiple layers of dielectric materials. When a layer is described as being coupled or connected to another layer, it is understood that the coupled or connected layer can include intervening elements present between the coupled or connected layers. In contrast, when an element is referred to as being "directly" connected or coupled to another layer, it is understood that there are no intervening elements between the layers. However, the presence of a directly coupled or connected layer does not exclude other connections in which intervening elements may be present.

[0030] Furthermore, the terms left, right, front, back, top, bottom, forward, reverse, clockwise, and counterclockwise are used for explanatory purposes only and are not limited to any fixed direction or orientation. Rather, they are merely used to indicate the relative position and / or orientation between various parts of an object and / or component.

[0031] In addition, for ease of description, the methods and processes described herein may be described in a particular order. However, it is understood that, unless the context otherwise dictates, intervening processes can occur before and / or after any part of the described process and can be reordered, added, and / or omitted according to various embodiments.

[0032] Unless otherwise indicated, all numbers expressing quantities, dimensions, etc. in this document should be understood to be modified in all instances by the term "about". In this application, unless specifically stated otherwise, the use of the singular includes the plural, and the use of the terms "and" and "or" means "and / or" unless otherwise indicated. Additionally, the use of the terms "including" and "having" and other forms (such as "includes", "included", "has", "have", and "had") should be considered non-exclusive. Moreover, terms such as "element" or "component" cover both elements and components that include one unit and those that include more than one unit, unless specifically stated otherwise.

[0033] As used herein, the phrase "at least one of" before a series of items (where the term "and" or "or" is used to separate any of the items) modifies the entire list, rather than each member (i.e., each item) of the list. The phrase "at least one of" does not require the selection of at least one of each listed item; rather, the phrase allows for the meaning of including at least one of any one of the items and / or at least one of any combination of the items. For example, the phrases "at least one of A, B, and C" or "at least one of A, B, or C" each refer to only A, only B, or only C; and / or any combination of A, B, and C. In examples where it is intended to select "at least one of each of A, B, and C" or alternatively "at least one of A, at least one of B, and at least one of C", it is described explicitly as such.

[0034] One general aspect includes an alignment structure for an optical component. The alignment structure further includes an aligner that may include a plurality of sections joined together to provide a semi-closed open space configured to allow the body of a first optical component to be inserted into an alignment position to align with a second optical component. The plurality of sections may include a bottom section having a front edge facing the semi-closed open space for receiving a shelf extending from the second optical component. The plurality of sections further includes a pair of side sections respectively joined to the bottom section and separating the semi-closed open space by a first distance to allow the body of the first optical component to be lowered from the top. The plurality of sections further includes a front section joined to the pair of side sections. The front section is configured to be positioned as a support bar on the surface of the second optical component while the shelf and a portion of the second optical component are inserted below the support bar in the semi-closed open space, and the shelf is for supporting the body of the first optical component in the alignment position.

[0035] An embodiment may include one or more of the following features. The structure, wherein the pair of side sections may include a top ridge near the outer wall of each side section and an inclined facet extending downward from the top ridge to the inner wall of each side section, wherein the two inner walls of the pair of side sections are separated by a first distance. The inclined facets on each side section are configured to guide the body of the first optical component into the semi-closed open space until it is located on the shelf, wherein the body of the first optical component has a width less than the first distance. Each side section may include an edge step in a vertical direction relative to the bottom section. The edge step is positioned at the central region of the inner wall to increase the first distance to a second distance for the section of the semi-closed open space extending backward from the central region, to allow a small amount of horizontal rotational freedom within the semi-closed open space to position the body of the first optical component on the shelf in an aligned position. The pair of side sections may include two first L-shaped end sections joined to the front section, the two first L-shaped end sections providing a stop for the body of the first optical component to maintain a gap from the first optical component in the aligned position to the second optical component. The pair of side sections may include two second L-shaped end sections separated by a third distance, the third distance being less than the first distance but sufficient to allow a ribbon fiber to exit the semi-closed open space from the body of the first optical component and to provide an additional amount of horizontal translational freedom within the semi-closed open space to align the body of the first optical component on the shelf with the second optical component. The aligner is configured to maintain a gap from itself to both the body of the first optical component and the shelf when the body of the first optical component is in the aligned position on the shelf within the semi-closed open space. The aligner is a single part for aligning a fiber array unit (FAU) connector with a lens at the side edge of a photon integrated circuit (PIC) chip, the PIC chip having a package bottom from which the shelf extends. The structure may include: a support frame for providing corresponding surfaces for the aligner and the shelf to engage; and a flip cover for covering and holding the body of the FAU connector in the aligned position on the shelf by latching to the support frame, the support frame being attached to the package structure of the PIC chip in a floating state.

[0036] Another general aspect includes an apparatus for aligning an optical fiber array unit (FAU) connector with a photonic integrated circuit (PIC). The apparatus further includes an aligner having a front section and a bottom section that are respectively coupled to two side sections spaced a first distance apart. The front section and the bottom section are configured to expand a semi-closed open space between the two side sections for receiving a shelf that extends beyond a lens at a side edge of the PIC chip. The shelf has alignment features associated with the lens. The front section is configured as a support bar positioned on the surface of the PIC chip, and the semi-closed open space between the two side sections allows the body of the FAU connector to be loaded from the top down to be located on the shelf in the semi-closed open space and aligned with the lens through the alignment features.

[0037] An embodiment may include one or more of the following features. The device, wherein each of the two side sections may include an inner side facing the semi-closed open space, an outer side opposite the inner side, a narrow top ridge near the outer side, and an inclined facet extending from the top ridge downward to the inner side for guiding the body of the FAU connector downward onto the shelf in the semi-closed open space between the two inner sides of the two side sections, the body of the FAU connector having a width equal to or less than the first distance. The inner side may include an edge step in the vertical direction located at the central region of the side section. The edge step increases the first distance to a second distance for a section of the semi-closed open space extending backward from the central region to allow a small amount of horizontal rotational freedom within the semi-closed open space to align the body of the FAU connector on the shelf with the lens at the side edge of the PIC chip. The two side sections may include two first L-shaped end sections joined to the front section. The two first L-shaped end sections provide a hard stop for the body of the FAU connector to control the distance between the lens of the FAU connector and the lens at the side edge of the PIC chip. The alignment feature may include a pair of V-shaped grooves configured to be matched by a pair of alignment rods mounted on the body of the FAU connector for establishing optical alignment between the lens of the FAU connector and the lens at the side edge of the PIC chip. The two side sections may include two second L-shaped end sections spaced apart by a third distance, the third distance being less than the first distance but sufficient to allow the ribbon fiber of the FAU connector loaded on the shelf in the semi-closed open space to pass through. The two second L-shaped end sections are configured to provide an additional amount of horizontal translational freedom within the semi-closed open space to align the body of the FAU connector loaded on the shelf with the lens at the side edge of the PIC chip. The shelf is part of a package structure attached to the bottom of the PIC chip by epoxy resin. The device may include a frame for providing corresponding support surfaces for the bottom section and the shelf to engage. The frame is attached to the package structure of the PIC chip in a floating state. The device may include a flip cover coupled to the frame via a pivot pin. The flip cover is configured to lift open to allow the body of the FAU connector to be loaded onto the shelf in the semi-closed open space, and to close to hold the body of the FAU connector in an aligned position on the shelf by latching with the frame.

[0038] Another general aspect includes a method for aligning an optical fiber array unit (FAU) connector with a photonic integrated circuit (PIC). The method further includes attaching a frame to a package structure of the PIC chip to provide a support surface in a floating state. One of the support surfaces is configured to be bonded to a pair of shelves by an epoxy resin, each shelf having alignment features respectively associated with two lenses of the PIC chip. The method further includes placing a pair of aligners on the frame. Each aligner may include a front section and a bottom section that are respectively combined with two side sections spaced apart by a first distance to provide a semi-enclosed open space configured to receive one of the pair of shelves as a front section positioned on the top surface of the PIC chip. One of the support surfaces of the frame is configured to be bonded to the bottom section of each aligner by an epoxy resin. The method further includes loading a pair of bodies of the FAU connector onto the pair of shelves in the semi-enclosed open spaces of the pair of aligners respectively. Each body has a small degree of horizontal rotational freedom in the corresponding semi-enclosed open space and a translational freedom along a direction parallel to the two side sections. The method further includes adjusting each body of the FAU connector to an alignment position on the corresponding shelf via the alignment features to achieve optical alignment between the lens of the FAU connector and one of the two lenses of the PIC chip. The method also includes curing the epoxy resin between each shelf and the corresponding one of the support surfaces to fix the shelf and the body of the FAU connector in the alignment position. The method further includes curing the epoxy resin between each aligner and the corresponding one of the support surfaces of the frame to fix the position of the aligner to ensure a non-contact gap between the body of the FAU connector and the aligner.

[0039] As used herein, phrases such as "aligner", "frame", "shelf" refer to mechanical parts having certain irregular shapes. The different sections of the irregular shapes are designed separately and together for different aspects of the function, such as supporting, guiding, adjusting, and restricting the alignment of an optical component with another optical component. For example, the aligner can be made of molded plastic or die-cast, machined, or stamped sheet metal. The frame can be made of machined nickel-plated copper tungsten or copper tungsten by metal injection molding or other strong materials that can absorb possible high external loads and have a low coefficient of thermal expansion to match the thermal expansion coefficient of the photonic integrated circuit material. The shelf is referred to as a piece protruding from a wall (or something with vertical side edges) and is a structure that extends side edges from the bottom of the package structure of the circuit chip in this article. A preferred material can be glass, the same as the material of the connector body located above to achieve firm and reliable optical alignment.

[0040] Figure 2 Shows an alignment structure as an independent part according to an embodiment of the present technology. In the embodiment, as Figure 2(Part A) shows that the alignment structure 100 includes a pair of side sections 120, the pair of side sections 120 being spaced apart and combined with the bottom section 110 to provide a semi-closed open space 101 between the two inner walls of the pair of side sections 120. Each side section 120 includes a first L-shaped end section 140 combined with the front section 130. Portions of the front section 130 and portions of the bottom section 110 are removed to obtain a cutout space 111 that becomes part of the semi-closed open space 101. This alignment structure 100 (referred to simply as the aligner in the remainder of the specification) is configured to have the front section 130 serve as a support rod placed at the side edge of the PIC chip, while providing the cutout space 111 for receiving the shelf (13) of the optical IO port extending out of the PIC chip (see Figure 1 ).

[0041] In the embodiment shown in Figure 2 (Part B), the top view of the aligner 100 shows that a first distance d1 is provided for the semi-closed open space between the two inner walls of the pair of side sections 120. Each side section 120 has a narrowed top ridge region 121 near the outer wall of the side section 120. On the inner side, the top ridge region 121 is followed by an inclined facet 122 to combine with the vertical inner wall of the side section 120, where the two inner walls are spaced apart by the first distance d1 to provide the semi-closed open space 101. The first distance d1 is at least slightly wider than the body of the FAU connector (14) to allow the latter to be loaded downward (from the top) into the semi-closed open space 101. On the central region of the inner wall 120, there is an edge step 125 extending vertically downward to the bottom section 110 to impart a second distance d2 from the central region between the two inner walls toward the rear section before the two L-shaped end sections 150. The second distance d2 is slightly greater than the first distance d1. It is configured to provide some rotational freedom for the body of the FAU connector (14) to be placed inside the semi-closed open space 101. Two second L-shaped end sections 150 combined with the pair of side sections 120 and jointly combined with the bottom section 110 provide a gap of a third distance d3 between the two second L-shaped end sections 150 at the rear section of the aligner 100. The third distance d3 is less than the first distance d1, but wide enough to allow the ribbon optical fiber (15) to pass out of the semi-closed open space 101.

[0042] In the embodiment shown in Figure 2In the embodiment shown in (Part C), the front view of the aligner 100 illustrates that the front section serves as a support bar, and its surface is for resting on the surface near the side edge of the PIC chip. The dashed box indicates the cutout space 111 on the proximal side, which allows the insertion of the shelf (13) when the aligner 100 is placed against the side edge of the PIC chip. This figure also clearly shows the first distance d1 between the two inner walls of the semi-closed open space 101 and the third distance d3 (d3 < d1) between the two second L-shaped end sections 150 at the rear end section of the aligner 100.

[0043] Figure 3 A perspective view showing the body of an FAU connector for alignment with a PIC chip to establish optical I / O via the alignment structure provided in the present disclosure. Figure 3 Part A of shows the top surface of the body of the FAU connector 14, with one side attached to the lens 141 (which may include a microlens array) and the other side coupled to the ribbon optical fiber 15. Figure 3 Part B of shows the alignment features associated with the present technology, with two alignment rods 145 attached to corresponding V-shaped grooves located in the bottom surface near and parallel to the two sides of the body of the FAU connector 14. When the body of the FAU connector 14 is loaded, the alignment structure 100 is configured to guide the body of the FAU connector 14 downward onto the top surface of the shelf (13). The top surface of the shelf (13) also includes two V-shaped grooves configured to receive the two alignment rods. These V-shaped grooves are pre-built alignment features in the shelf and extend from the package structure beyond the corresponding side edges of the PIC chip (see Figure 1 ) to the lens of the optical I / O at the side edge of the PIC chip where the shelf under the PIC chip is pre-aligned.

[0044] Figure 4 is a perspective view of an embodiment according to the present technology in which the aligner is positioned and receives the shelf 13 extending from the PIC chip within a semi-closed open space, and a same configuration adjacent to said configuration but in which the FAU connector is placed on the shelf 13 by the same aligner. In the embodiment, the aligner is a part of an optical connector for a photonic integrated circuit (PIC) chip (e.g., a silicon photonics-based IC with optical input / output co-packaged with an electronic switch IC). As shown, generally in line with Figure 2The aligners 100 with the same alignment structure shown in the figure are arranged in pairs in the frame structure 200 at the designated connector positions located at the side edges of the PIC chip. When each of the pair of aligners 100 is arranged in the frame structure 200, the aligner 100 has a support rod 130 positioned on the surface 115, near the side edge of the PIC chip, to hold the aligner 100 in a state matching that of the PIC chip. At the same time, the shelf 13 extending out of the side edge of the PIC chip is completely received in the cutout space ( Figure 2 designated as 102) provided by one of the pair of aligners 100. The aligner 100 is in the proper position relative to the frame structure 200, that is, it is designed to guide the body of the FAU connector 14 downward to the position of the shelf 13. The shelf 13 includes a pair of V-shaped grooves 135 (only one is visible in this perspective view) along both sides of the shelf on the surface. In an embodiment, the shelf 13 is configured to serve as a support for the body of the FAU connector 14 loaded (or inserted) from the top, as illustrated in the adjacent ones of the pair of aligners 100. The V-shaped grooves 135 in the shelf 13 are configured to receive the alignment rods (designated as 145 in Figure 3 ) on the body of the FAU connector 14 to ensure that the body of the FAU connector 14 is inserted into the alignment position, so that the lens 141 of the FAU connector 14 is optically aligned with the lens 111 at the side edge of the PIC chip.

[0045] In an embodiment, the aligner 100 is placed in the proper position in the frame structure 200 such that the shelf 13 is completely received in the cutout space 102 with a surrounding gap (see Figure 2 ) without direct contact with each other. This is to ensure that the thermal expansion / contraction of the aligner 100 does not affect the sensitive optical alignment involving the shelf 13. Optionally, the aligner 100 can be glued to the bottom surface of the frame structure 200 to ensure this proper position, while the frame structure 200 is configured to be attached to the rigid cover structure 12 of the CPO-PIC assembly in a floating state. In another embodiment, once the optical alignment is achieved after loading the body of the FAU connector 14 onto the shelf 13, the bottom of the shelf can be glued to the bottom surface of the frame structure 200 by applying epoxy resin from the bottom side of the frame structure 200.

[0046] Figure 5 is a cross-sectional view showing the configuration in which the body of the FAU connector is guided downward to the shelf via the aligner according to an embodiment of the present technology and the adjacent configuration in which the body of the FAU connector is in the alignment position and the alignment rod matches the V-shaped groove in the shelf of the next aligner. In an embodiment, Figure 5A method for loading the body of the FAU connector 14 (which can be manually by an operator) into a semi-closed open space provided by the aligner 100 (indicated as 101 in Figure 2 ) is described. Specifically, the semi-closed open space 101 is the space between two side sections of the aligner 100 and above the shelf 13. As shown in the left part of Figure 5 , the body of the FAU connector 14 is lowered from the top, as indicated by the arrow. The aligner 100 is configured to have two inclined facets 122 extending downward from the outer walls of the respective two side sections to the inner walls (see Figure 2 ). This inclined configuration provides a guide or funnel for loading the body of the FAU connector 14 downward until it reaches the shelf 13. The spacing between the inner walls labeled d1 is slightly greater than the width of the body of the FAU connector 14. As shown in the right side of Figure 5 , the two alignment rods 145 at the bottom of the body of the FAU connector 14 can be easily positioned in the V-shaped grooves (labeled 135 in Figure 4 ) formed in the top surface of the shelf 13 by means of minor manual adjustment. In an embodiment, since the shelf 13 and the associated V-shaped grooves as alignment features have been pre-aligned for a specific lens 111 of the optical IO at the side edge of the PIC chip, once the two alignment rods 145 match the associated V-shaped grooves in the shelf 13, the body of the FAU connector 14 will be set to the alignment position. In other words, the lens of the FAU connector in the alignment position should be aligned with the lens 111 of the PIC chip. As shown in Figure 5 , the two aligners 100 are placed in two adjacent positions within a frame structure 200.

[0047] Figure 6 is a top view showing the body of the FAU connector loaded in the semi-closed open space according to an embodiment of the present technology, having hard stops at the front and rear, rotational freedom and translational freedom for facilitating alignment with the shelf. Similar to the configuration shown on the right side of Figure 5 , the body of the FAU connector 14 has been loaded downward from the top onto the shelf (not visible in this figure). Ideally, when the alignment rods fit into the V-shaped grooves, it will be in its alignment position on the shelf (see Figure 5)。In fact, it may need to make some fine adjustments by laterally moving within the semi-closed open space between the two inner sidewalls of the pair of side sections of the aligner 100. The aligner 100 is configured to have a semi-closed open space with a first distance d1 slightly greater than the width of the body of the FAU connector, such that it can have a degree of freedom of movement in the left / right direction in this top view angle. In the length direction, the aligner 100 includes two first L-shaped end sections 140 to provide a hard stop 142 to prevent the body of the FAU connector 14 from moving forward until a certain point, at which the lens 141 of the FAU connector is at a fourth distance d4 from the lens 111 of the PIC chip, and the fourth distance d4 can be a controlled ideal spacing for achieving excellent optical coupling between the two lenses.

[0048] In another embodiment, the length of the semi-closed open space has at least a fifth distance d5 greater than the length of the body of the FAU connector 14. The rear end of the body of the FAU connector is a gap at a fifth distance d5 from the second L-shaped end section 150 of the aligner 100. The second L-shaped end section 150 also serves as a hard stop for the body of the FAU connector 14 at the rear end of the aligner 100. This gap of the fifth distance d5 allows the body of the FAU connector 14 to have sufficient translational freedom within the semi-closed open space to seek its ideal alignment position. In yet another embodiment, each of the two side sections 120 includes an edge step that is vertically oriented in the horizontal direction relative to the body of the FAU connector 14. The edge step is located near the central region of the two side sections, expanding the spacing between the two inner sidewalls from the first distance d1 to a second distance d2 from the central region backward to the second L-shaped end section 150. This provides a small degree of rotational freedom for the body of the FAU connector 14 within the semi-closed open space, as Figure 6 schematically illustrated by the body of the dashed line. These translational or rotational degrees of freedom introduced by the designed gaps between the loaded FAU connector body and the inner sidewalls of the aligner facilitate alignment and avoid strenuous efforts during the fine adjustment process.

[0049] In yet another embodiment, the alignment structure (referred to as the aligner 100) of the present technology is placed at a designated position defined by the frame 200 based on the position of the optical IO at the side edge of the PIC chip. In a specific embodiment, as Figure 7 shown, for each frame structure 200, two positions are provided for placing two aligners 100 next to each other. Each of the two positions is directly associated with the position of the lens of the PIC chip at the side edge. A shelf having corresponding alignment features associated with this lens is attached to the lower side of the package structure of the PIC chip and extends out of the side edge. The frame 200 is attached to a CPO-PIC assembly designed to encapsulate along the side edge of the PIC chip (see Figure 1)'s cover structure 12 such that two shelves are included in the frame 200. Then, each of the two aligners 100 is placed in the corresponding one of two positions to receive the corresponding one of the two shelves. Each aligner 100 further provides a guide for loading one FAU connector 14 (as shown in Figure 6 ) onto the shelf to achieve alignment between the lens of the FAU connector and the corresponding lens of the PIC chip for forming an optical IO of the CPO-PIC assembly.

[0050] In yet another embodiment, Figure 7 it is also shown that the formation of the optical connector of the CPO-PIC assembly involves another feature part, namely a flap 300 for covering each aligner 100 in a specified position when the body of the FAU connector 14 is loaded. As shown in Figure 7 , the flap 300 is coupled to the frame 200 via a pivot pin 305, which allows the flap 300 to open to an upright position or close to a position above the aligner 100 and the body of the FAU connector loaded in the semi-closed open space. Figure 7 The open position of the flap 300 is shown, revealing a tab plate 303 connected to the bottom surface of the flap 300 at a downwardly inclined angle (but < 90°). In addition, the flap 300 is configured to have two additional tab plates 301 and 302 connected to the two side edges of the flap 300 at 90°. One tab plate 302 is in a straight shape for sliding down along the straight side wall of the central pillar on the frame 200 when the flap 300 rotates to the closed state. The other tab plate 301 has a hook-shaped end for latching with the stepped pillar on the frame 200 when the flap 300 is in the closed state. This is shown in Figure 8 as the case when the flap 300 rotates from the open position to the closed position via the pivot pin 305 to cover the aligner 100, and the angled tab plate 303 can be configured to press on the top of the body of the FAU connector 14 with spring force to fix the alignment position of the lens alignment between the FAU connector and the PIC chip.

[0051] In an alternative aspect, the present technology provides a method for supporting alignment of optical input / output (IO) of a co-packaged optical device - photonic integrated circuit (CPO-PIC) assembly. Figure 9A flowchart showing a method 900 for aligning an optical fiber array unit (FAU) connector with a photonic integrated circuit (PIC) in an embodiment of the present technology is presented. Method 900 includes a step 910 for attaching a frame that includes a support surface in a floating state, the support surface being configured to support a shelf having alignment features associated with a lens of a photonic chip of a package structure that attaches the frame to a PIC chip. The PIC chip (such as a silicon-based photonic integrated optical transceiver co-packaged with an electrical switch module) needs to have an optical I / O. The FAU connector is used to form an optical I / O by coupling the lens of the FAU connector with the lens at the side edge of the PIC chip. In a particular embodiment, the frame is attached to a cover structure of a CPO-PIC assembly (labeled 12 in Figure 1 ). The cover structure is a rigid and sturdy fixture that is the top part of the package structure of the CPO-PIC assembly, and its bottom part is configured to attach the shelf. Thus, the frame provides a support surface to allow forces (the weight of the body of the FAU connector and other forces applied by the operator during loading of the FAU connector) to be effectively transmitted through the shelf to the frame and further to the cover structure. In an embodiment, the frame is attached to the cover structure with minimal physical contact. There is no direct contact with any part of the package structure of the CPO-PIC assembly below the support surface. Thus, it allows the optical structure to be supported in a floating state with minimal impact on temperature. In another embodiment, one of the support surfaces provided by the frame is configured to be bonded to a pair of shelves by epoxy resin, each shelf having alignment features associated with two lenses at one side edge of the PIC chip respectively.

[0052] Figure 9 It is also shown that method 900 includes a step 920 for placing an aligner on the frame. As Figure 2 illustrates, the aligner consists of a front section and a bottom section that are combined with two side sections spaced apart by a first distance respectively to provide a semi-closed open space. The bottom section and the front section are configured to further expand the semi-closed open space to receive the shelf of the PIC chip, such that the front section of the aligner is positioned on the surface of the PIC chip, and the bottom section is supported by one of the support surfaces of the frame. In an embodiment, the bottom section of the aligner is configured to be bonded to one of the support surfaces of the frame by epoxy resin. In an embodiment, the aligner is manually placed by an operator or assembler into the frame, into a position guided by the frame. In this position, the aligner can be used in its geometry to facilitate the placement of the body of the FAU connector and allow the lens of the FAU connector to be aligned with the lens at the side edge of the PIC chip. This function and its benefits have been presented in the previous paragraphs and from Figures 1 through 8A description will be given. Meanwhile, this position will ideally maintain a non-contact gap with the shelf to avoid a direct impact on the optical alignment between the lens of the FAU connector and the lens of the PIC chip due to thermal expansion or contraction of the encapsulation material. Stress measurements indicate that little stress is exhibited in the frame, aligner, and shelf that are subjected to a temperature change from 150 °C to 80 °C. In some embodiments, step 920 includes placing a pair of aligners having the same structure in a side-by-side configuration into each frame. The two aligners are to be bonded to one of the support surfaces of the frame with epoxy to fix the corresponding positions with a non-contact gap from a pair of corresponding shelves.

[0053] Referring Figure 9 , method 900 further includes step 930 for loading the body of the FAU connector onto a shelf in a corresponding semi-enclosed open space of the aligner. The side sections of the aligner serve as guides to lower the body of the FAU connector from above into the semi-enclosed open space until it is on the shelf received via the cutout space when the aligner is placed in the frame. In an embodiment, each of the two side sections includes a narrow top ridge connected to the inner wall via an inclined facet, forming a funnel-shaped structure for loading the body of the FAU connector from the top. In particular, this provides a funnel effect to assist the operator in manually picking up the body and lowering it down onto the shelf.

[0054] Referring again Figure 9 , method 900 includes step 940 for adjusting the body of the FAU connector to an alignment position on the shelf via alignment features to achieve optical alignment between the lens of the FAU connector and the lens of the PIC chip. In an embodiment, the semi-enclosed open space is configured to have a width greater than the width of the body of the FAU connector as shown in Figure 6 , that is, a first distance d1 separated by the two inner walls of the two side sections (see Figure 2 ). Additionally, each of the two inner walls has an edge step to further space apart the rear portions of the two inner walls by a second distance, providing horizontal rotational freedom. This rotational freedom allows for easier adjustment of the body of the FAU connector to find the corresponding alignment position via the alignment features in the shelf. Furthermore, the semi-enclosed open space is also designed to have a length greater than the length of the body to provide sufficient translational freedom for facilitating alignment. In an embodiment, the length of the semi-enclosed open space is determined by a first L-shaped end section and a second L-shaped end section that respectively connect the two side sections to the front section of the aligner and connect the two side sections at the rear end of the aligner. The first L-shaped end section also provides a hard stop to prevent the lens of the FAU connector from contacting the lens at the side edge of the PIC chip, instead providing a gap distance that can be pre-determined to ideally enhance the optical coupling between the two lenses.

[0055] In an embodiment, method 900 further includes step 950 for curing the epoxy resin between each shelf and the corresponding one of the support surfaces to fix the shelf and the body of the upper FAU connector in an aligned position. As in step 910, when the frame is attached to the package structure of the PIC chip, the shelf is supported by one of the support surfaces provided by the frame. However, the support is non - engaging. In an embodiment, the support surface provided by the frame includes a plurality of through - holes, and when the frame is attached to the package structure of the PIC chip in a floating state, there are no other solid structures below the bottom side of the support surface. Using these through - holes, the epoxy resin can be dispensed into the interface between the shelf and the support surface without curing. Only when the loading and alignment of the FAU connector are achieved, step 950 is performed to bond the shelf to the support surface to ensure the alignment between the lens of the FAU connector and the lens of the PIC chip.

[0056] In another embodiment, method 900 further includes step 960 for curing the epoxy resin between each aligner and the corresponding one of the support surfaces of the frame to fix the position of the aligner to ensure a non - contact gap between the body of the FAU connector and the aligner. When the aligner is placed in the frame in step 920, the aligner provides a semi - enclosed open space to receive the shelf with a non - contact gap and is ready to allow the body of the FAU connector to be loaded onto the shelf, while the bottom section of the aligner is supported by one of the support surfaces of the frame. However, the support is non - engaging, while the aligner functions to guide the body of the FAU connector into the semi - enclosed open space and assist it in finding its alignment position on the shelf. Once this alignment position is reached, step 950 can be performed to fix the position of the shelf on the support surface of the frame by curing the epoxy resin. Then, step 960 can be performed to cure the epoxy resin to ensure the support position of the aligner on the support surface of the frame. This position will maintain the non - contact gap between the aligner and the shelf and the body of the FAU connector located above the shelf. Also, the epoxy resin can be pre - dispensed through the plurality of through - holes in the bottom section into the interface between the bottom of the aligner and the support surface of the frame.

[0057] In another embodiment, the frame can be associated with a flip - cover. Method 900 can include the step of rotating the flip - cover from an open state to a closed state via a pivot pin coupled to the frame. Optionally, there are two flip - covers coupled to the frame via a single pivot pin. In steps 920, 930, and 940, the flip - covers are in an open state to allow the placement of the aligner, the loading of the body of the FAU connector, and the adjustment of the body of the FAU connector to reach the alignment position. Method 900 can include the step of closing the flip - cover such that it can apply a force on the top of the body of the FAU connector to hold it in the alignment position by latching the flip - cover to the frame.

[0058] Although the foregoing is a complete description of specific embodiments, various modifications, alternative constructions, and equivalents may be used. Accordingly, the above description and illustration should not be regarded as limiting the scope of the invention as defined by the appended claims.

Claims

1. An alignment structure for an optical component, comprising: An aligner comprising a plurality of sections joined together to provide a semi-enclosed open space configured to allow a body of a first optical component to be loaded into an alignment position for alignment with a second optical component, the plurality of sections comprising: a bottom section having a front edge facing a portion of the semi-enclosed open space for receiving a shelf extending out of the second optical assembly; a pair of side sections respectively combined with the bottom section and separating a first width of the semi-enclosed open space to allow the main body of the first optical component to be lowered from the top; and A front section combined with the pair of side sections, the front section is configured to be positioned on a support rod on the surface of the second optical component, while the shelf and a portion of the second optical component are inserted under the support rod in the semi-enclosed open space, and the shelf is used to support the main body of the first optical component in the aligned position.

2. The alignment structure of claim 1 , wherein the pair of side segments include a top ridge proximate an outer wall of each side segment and an inclined facet from the top ridge down to an inner wall of each side segment, wherein the two inner walls of the pair of side segments are separated by the first width.

3. The alignment structure of claim 2, wherein the inclined facets on each side segment are configured to guide the body of the first optical component into the semi-enclosed open space until it is located on the shelf, wherein the body of the first optical component has a width less than the first width.

4. The alignment structure according to claim 3, wherein each side segment includes an edge step in a vertical direction relative to the bottom segment, and the edge step is positioned at the central area of ​​the inner wall to increase the first width for the segment from the central area to the rear of the semi-enclosed open space to allow a small amount of horizontal rotational freedom within the semi-enclosed open space to place the main body of the first optical component on the shelf at the alignment position.

5. The alignment structure of claim 1 , wherein the pair of side segments include two first L-shaped end segments combined with the front segment, the two first L-shaped end segments providing stops for the main body of the first optical component to maintain a gap from the first optical component to the second optical component in the alignment position.

6. The alignment structure of claim 1 , wherein the pair of side segments include two second L-shaped end segments separated by a second width, wherein the second width is narrower than the first width but sufficient to allow the ribbon optical fiber to pass from the body of the first optical component out of the semi-enclosed open space and to provide an additional amount of horizontal translational freedom within the semi-enclosed open space to align the body of the first optical component on the shelf with the second optical component.

7. The alignment structure according to claim 1, wherein the aligner is configured to maintain a gap between itself and both the body of the first optical component and the shelf when the body of the first optical component is in the aligned position on the shelf in the semi-enclosed open space.

8. The alignment structure of claim 1, wherein the aligner is a single part for aligning a fiber array unit (FAU) connector with a lens at a side edge of a photonic integrated circuit (PIC) chip having a package bottom from which the shelf extends.

9. The alignment structure of claim 8, further comprising: a support frame for providing corresponding surfaces for the aligner and the shelf to engage; and a flip cover for covering and holding the body of the FAU connector in the aligned position on the shelf by latching with the support frame, the support frame being attached to the packaging structure of the PIC chip in a floating state.

10. A device for aligning a fiber array unit (FAU) connector with a photonic integrated circuit (PIC), comprising: An aligner having a front section, a rear section and a bottom section, which are respectively combined with two side sections spaced apart by a first distance, the front section and the bottom section being configured to expand a semi-enclosed open space between the two side sections for accommodating a shelf of a lens extending beyond a side edge of a PIC chip, the shelf having an alignment feature associated with the lens, the front section being configured as a support rod positioned on a surface of the PIC chip, the semi-enclosed open space between the two side sections allowing a body of the FAU connector to be loaded from top to bottom to be located on the shelf in the semi-enclosed open space and aligned with the lens through the alignment feature.

11. An apparatus according to claim 10, wherein each of the two side segments includes an inner side facing the semi-enclosed open space, an outer side opposite to the inner side, a narrow top ridge close to the outer side, and an inclined facet from the top ridge down to the inner side for guiding the body of the FAU connector downward to the shelf in the semi-enclosed open space between the two inner sides of the two side segments, the body of the FAU connector having a width equal to or less than the first distance.

12. The device according to claim 11, wherein the inner side includes an edge step in the vertical direction positioned at the central area of ​​the side segment, the edge step increasing the first distance to a second distance for a portion of the semi-enclosed open space from the central area to the rear segment to allow a small amount of horizontal rotational freedom within the semi-enclosed open space to align the body of the FAU connector on the shelf with the lens at the side edge of the PIC chip.

13. The device according to claim 10, wherein the two side sections include two first L-shaped end sections combined with the front section, and the two first L-shaped end sections provide hard stops for the body of the FAU connector to control the distance between the lens of the FAU connector and the lens at the side edge of the PIC chip.

14. The apparatus of claim 10, wherein the two side segments include two second L-shaped end segments spaced apart by a third distance, the third distance being smaller than the first distance but sufficient to allow the ribbon optical fibers of the FAU connectors loaded on the shelf in the semi-enclosed open space to pass through.

15. The apparatus of claim 14, wherein the two second L-shaped end sections are configured to provide an additional amount of horizontal translational freedom within the semi-enclosed open space to align the body of the FAU connector loaded on the shelf with the lens at the side edge of the PIC chip.

16. The apparatus of claim 13, wherein the alignment feature comprises a pair of V-grooves configured to be matched by a pair of alignment rods disposed on the body of the FAU connector for establishing optical alignment between the lens of the FAU connector and the lens at the side edge of the PIC chip.

17. The apparatus of claim 10, wherein the shelf is part of a package structure attached to a bottom of the PIC chip by epoxy.

18. The apparatus of claim 10, further comprising a frame to provide respective support surfaces for the bottom section and the shelf to engage, the frame being attached to a packaging structure of the PIC chip in a floating state.

19. The apparatus of claim 18, further comprising a flap coupled to the frame via a pivot pin, the flap being configured to lift open to allow the body of the FAU connector to be loaded onto the shelf in the semi-enclosed open space, and to close to hold the body of the FAU connector in the aligned position on the shelf by latching with the frame.

20. A method for aligning a fiber array unit (FAU) connector with a photonic integrated circuit (PIC), comprising: Attaching a frame to the packaging structure of the PIC chip to provide a support surface in a floating state, one of the support surfaces being configured to be bonded by epoxy to a pair of shelves, each shelf having alignment features respectively associated with two lenses of the PIC chip; placing a pair of aligners onto the frame, each aligner comprising a front section and a bottom section respectively combined with two side sections spaced a first distance apart to provide a semi-enclosed open space, the semi-enclosed open space being configured to receive one of the pair of shelves as the front section positioned on the top surface of the PIC chip, one of the support surfaces of the frame being configured to be bonded to the bottom section of each aligner by epoxy resin; Loading a pair of bodies of two FAU connectors onto the pair of shelves in the semi-enclosed open spaces of the pair of aligners, respectively, each body having a small amount of horizontal rotational freedom in the corresponding semi-enclosed open spaces and a degree of translational freedom along a direction parallel to the two side sections; adjusting each body of the FAU connector to an aligned position on the corresponding shelf via the alignment features to achieve optical alignment between a lens of the FAU connector and one of the two lenses of the PIC chip; curing the epoxy between each shelf and a corresponding one of the support surfaces to secure the shelf with the body of the FAU connector in the aligned position; and The epoxy between each aligner and the corresponding one of the support surfaces of the frame is cured to fix the position of the aligner to ensure a contact-free gap between the body of the FAU connector and the aligner.

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