Apparatus and method for supporting optical aligner

Abstract

The invention relates to an apparatus and a method for supporting an optical aligner. An apparatus for supporting two fiber array unit (FAU) connectors aligned with respective lenses of a photonic integrated circuit (PIC) includes a frame having a pair of arm sections joined with two side sections of a bottom section. The pair of arm sections is configured to be inserted in parallel into a package structure associated with a PIC chip to place the frame in a floating state. The bottom section provides a first support surface to support two aligners disposed from the top along the two side sections, respectively. Each aligner provides a semi-closed open space to receive a shelf extending from a side edge of the PIC chip. The shelf is characterized by an alignment feature associated with a lens of the PIC chip. The semi-closed open space allows the body of the FAU connector to be loaded onto the shelf from the top and aligned with the lens based on the alignment feature.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Patent Application No. 63 / 600,161, filed Nov. 17, 2023, which is commonly assigned and incorporated herein by reference in its entirety for all purposes. Technical Field

[0003] The present invention relates to devices and methods for supporting optical aligners in a co-packaged optical system. 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 the switch module. 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. As technology advances, these co-packaged optics need to be miniaturized through the application of silicon photonics integrated circuit (SPIC) technology. SPIC requires 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] The existing technology for inputting and receiving light from a silicon photonics integrated circuit is to actively align a fiber block via a pigtail and glue it in place using epoxy. The problem with pigtail fiber cables is that the structure can become very bulky and difficult to manage, especially for a CPO with a switch chip, 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. There is a major problem with the pigtail solution: if one of the hundreds of fiber cables accidentally breaks, then the entire structure becomes useless and must be scrapped. This can be very expensive. Therefore, it is desirable to provide a novel structure for optically aligning and placing a micro-optical connector for supporting optical I / O alignment in a co-packaged optical system. Summary of the Invention

[0006] On the one hand, the present disclosure provides a structure for supporting an optical alignment member, which includes: a frame including a plurality of sections joined together to provide a first support surface for engaging an aligner and a second support surface for engaging a shelf, the aligner being configured to provide a semi-closed open space for receiving the shelf including alignment features associated with a second optical component, and guiding a body of a first optical component from above onto the shelf to be aligned with the second optical component via the alignment features, the plurality of sections including: a bottom section providing a front edge to the first support surface and a rear end to the second support surface; a pair of side sections spaced apart and joined to two sides of the bottom section respectively from the front edge to the rear end; two shoulder sections each having a lower end joined to the pair of side sections at an upward angle at the front edge; and a pair of arm sections joined to upper ends of the two shoulder sections respectively to extend forward parallel to the pair of side sections, the pair of arm sections being configured to be horizontally inserted into a package structure of the second optical component to place the frame in a floating state.

[0007] On the other hand, the present disclosure provides an apparatus for supporting two fiber array unit (FAU) connectors aligned with corresponding lenses of a photonic integrated circuit (PIC), which includes: a frame having a pair of arm sections joined to two side sections of a bottom section, the pair of arm sections being configured to be parallelly inserted into a package structure associated with a PIC chip to place the frame in a floating state, the bottom section providing a first support surface for supporting two aligners respectively placed along the two side sections from above, each aligner providing a semi-closed open space for receiving a shelf extending from a side edge of the PIC chip, the shelf being characterized by alignment features associated with the lens of the PIC chip, the semi-closed open space allowing a body of the FAU connector to be loaded from above onto the shelf and aligned with the lens based on the alignment features.

[0008] On the other hand, the present disclosure provides a method for supporting the alignment of a fiber array unit (FAU) connector with a photonic integrated circuit (PIC), which includes: providing a frame having a bottom section coupled to two side sections, the two side sections further extending upwardly respectively to be coupled to a pair of arm sections at a position above but parallel to the two side sections; inserting the pair of arm sections into two holes in a package structure of a PIC chip to place the frame in a floating state to provide one of the support surfaces for supporting two shelves in the bottom section, the bottom section including a plurality of through holes configured to dispense epoxy resin for bonding the two shelves thereabove, each shelf extending beyond a lens at a side edge of the PIC chip and characterized by alignment features associated with the lens; and placing two aligners in the frame, each aligner having a front rod positioned on a surface of the PIC chip while having a bottom to be bonded by epoxy resin positioned on the other of the support surfaces in the bottom section of the frame, each aligner being configured to provide a semi-closed open space for receiving one of the two shelves without a contact gap. 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 array unit (FAU) connectors for optical input / output (IO) according to an embodiment of the present technology.

[0011] Figure 2 are a perspective view, a top view, and a side view of a frame for supporting an optical aligner to ensure optical alignment of an FAU connector with a PIC chip according to an embodiment of the present technology.

[0012] Figure 3 is a perspective view of a frame inserted into a package structure of a PIC chip and coupled to two covers in a closed position according to an embodiment of the present technology.

[0013] Figure 4 is a cross-sectional view of two holes in a package structure of a PIC chip and an enlarged view showing a specific shape of the two holes according to an embodiment of the present technology.

[0014] Figure 5A side view of a frame in an insert package structure according to an embodiment of the present technology, illustrating the floating state of the frame.

[0015] Figure 6 A perspective view of both the top and bottom of the body of an FAU connector with alignment bars according to an embodiment of the present technology.

[0016] Figure 7 A perspective view of a 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 the same configuration with an FAU connector loaded on the shelf but beside the said configuration.

[0017] Figure 8 A perspective view showing the bodies of four (two pairs) FAU connectors being loaded onto a shelf in a semi - enclosed open space provided by corresponding aligners supported by two (one pair) frames with the cover in the open position according to an embodiment of the present technology.

[0018] Figure 9 A perspective view showing the bodies of four (two pairs) FAU connectors on a corresponding shelf with the cover in the closed position according to an embodiment of the present technology.

[0019] Figure 10 A flowchart showing a method for supporting alignment between an FAU connector and a PIC chip according to another embodiment of the present technology. Detailed Description

[0020] The present disclosure provides a structure for supporting alignment of a fiber array unit (FAU) connector with a photonic integrated circuit (PIC). The structure includes a frame having a pair of arm sections coupled to two side sections of a bottom section. The pair of arm sections are configured to be inserted parallelly into a package structure associated with a PIC chip to place the frame in a floating state. The bottom section provides a first support surface to support two aligners respectively disposed along the two side sections from the top. Each aligner provides a semi - enclosed open space to receive a shelf extending from a side edge of the PIC chip. The shelf is characterized by alignment features associated with a lens of the PIC chip. The semi - enclosed open space allows the body of the FAU connector to be loaded onto the shelf from the top and to be aligned with the lens based on the alignment features. There are also additional embodiments.

[0021] In an embodiment, the present technology relates to providing a solution for an operator to support an alignment structure for inserting and fixing a micro - fiber array unit (FAU) connector relative to a co - packaged optics (CPO) - photonic integrated circuit (PIC) assembly. Figure 1A perspective top view of a CPO-PIC assembly 10 showing up to 16 FAU connectors 14 with optical input / output at four side edges of a PIC chip according to an embodiment of the present technology. The CPO-PIC assembly 10 includes a package structure 12 fixed on a substrate, with a switch module 11 attached at the center, where optical input / output (IO) ports are configured at the respective four sides (indicated by dashed lines 17) of the PIC chip. The package structure 12 is configured to place an aligner 100 to allow each of the 16 FAU connectors 14 to be positioned at each edge of the respective side 17 of the PIC chip (not visible below the package structure 12) to establish optical coupling with the IO ports of the CPO-PIC assembly 10. The FAU connectors 14 include small bodies followed by ribbon optical fibers 15. The bodies of the FAU connectors 14 are made of glass, translucent, 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 robust part for the optical connectors of the CPO-PIC assembly 10. Specifically, the aligner 100 enables an operator to (e.g., by hand) place the body of the FAU connector 14 into a position to establish a microscopic alignment between the lens at the front end of the body of the FAU connector 14 and the 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 shelves 13 extending from each IO port at the side edge of the PIC chip. The shelves 13 contain alignment features (not visible from Figure 1 invisible), which are configured to assist in the alignment between the lens at the front end of the body of the FAU connector 14 and the lens associated with the IO port of the PIC chip. The aligner 100 is configured to provide cutout spaces to fit into the shelves 13 to allow the body of the FAU connector 14 to be attached to the shelves and fixed in the aligned position using the alignment features on the shelves 13.

[0022] The optical connector for the CPO-PIC assembly 10 also includes other parts for supporting the aligner 100. In an embodiment, the aligner 100 is configured to rest partially on the surface of the PIC chip and is partially supported by the bottom surface of the frame 200, which is attached to the package structure 12 in a floating state. The "floating state" is referred to herein as the physical state of the frame relative to its environment, which provides a partial attachment at the side of the frame without any direct bottom support. The frame 200 also provides a bottom section with a support surface to support the shelf 13 in the floating state. The CPO-PIC assembly with multiple FAU connectors assisted by the aligner 100 must undergo numerous quality tests, including shock and vibration, unbiased damp heat, and fiber optic tensile tests. In all these tests, the aligner 100 provided by the present technology is configured to use the cover 300 (which is coupled to the frame 200 via a pivot pin to open or close) to apply a force from the top to fix the body of the FAU connector 14 to stay in the alignment position relative to the PIC chip and with a minimum optical input / output power change.

[0023] The following description is presented to enable a person having ordinary skill in the art to make and use the invention and to 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 presented embodiments, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0024] 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.

[0025] The reader is cautioned to note all papers and documents that are filed with and published with this specification for public inspection, and the content of all such papers and documents is 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 generic series of equivalent or similar features.

[0026] Moreover, any element in a claim that does not explicitly recite 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 35 U.S.C. § 112, paragraph 6. In particular, the use of “step of...” or “act of...” in a claim herein is not intended to invoke the provisions of 35 U.S.C. § 112, paragraph 6.

[0027] When an element is referred to herein as being “connected” or “coupled” to another element, it is to be understood that the element can be directly connected to the other element or that intervening elements may be present between the elements. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, it is to be understood that no intervening elements are present in the “direct” connection between the elements. However, the presence of a direct connection does not exclude other connections in which intervening elements may be present.

[0028] When an element is referred to herein as being “disposed” relative to another element in some manner (e.g., disposed on another element, disposed between another element, disposed under another element, disposed adjacent to another element, or disposed in some other relative manner), it is to be understood that the element can be directly disposed relative to the other element (e.g., directly disposed on another element) or that intervening elements may be present between the elements. In contrast, when an element is referred to as being “directly disposed” relative to another element, it is to be understood that no intervening elements are present in the “direct” instance. However, the presence of a direct disposition does not exclude other instances in which intervening elements may be present.

[0029] Similarly, when an element is referred to herein as being “joined” to another element, it is to be understood that the element can be directly joined to the other element (without any intervening elements) or that intervening elements may be present between the joined elements. In contrast, when an element is referred to as being “directly joined” to another element, it is to be understood that no intervening elements are present 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 portion of a single-piece rigid structure is referred to herein as being “connected” to another section or portion of the same structure, it is to be understood that the section or portion can be an inseparable part of the single-piece rigid structure that is specifically named to provide some unique function compared to other sections or portions. The single-piece rigid structure can be machined or cast or 3D printed as a whole. Alternatively, all sections or portions of the rigid 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 bonding, or chemical bonding. The technology focuses on their individual or overall function as a single-piece rigid structure and should be applicable to any manufacturing method.

[0030] Similarly, when an element is referred to as a "layer" herein, it should be understood that the layer can be a single layer or include multiple layers. For example, a conductive layer can include various different conductive materials or multiple layers of different conductive materials, and a dielectric layer can include various dielectric materials or multiple layers of dielectric materials. When a layer is described as being coupled or connected to another layer, it should be understood that the coupled or connected layer can include intermediate 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 should be understood that there are no intermediate elements between the layers. However, the presence of directly coupled or connected layers does not exclude other connections where intermediate elements can be present.

[0031] Furthermore, the terms left, right, front, back, top, bottom, forward, reverse, clockwise, and counterclockwise are for illustrative purposes only and are not limited to any fixed direction or orientation. Rather, they are merely used to indicate the relative positions and / or orientations between various parts of an object and / or component.

[0032] In addition, for ease of description, the methods and processes described herein can be described in a specific order. However, it should be understood that, unless the context otherwise requires, intermediate processes can occur before and / or after any part of the described process, and can be reordered, added, and / or omitted further various processes according to various embodiments.

[0033] Unless otherwise indicated, all numbers used herein to express quantities, dimensions, etc. 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 unless otherwise indicated, the use of the terms "and" and "or" means "and / or". Furthermore, the use of the terms "including" and "having" and other forms (e.g., "includes", "included", "has", "have", and "had") should be considered non-exclusive. Also, 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.

[0034] 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 selection of at least one of each listed item; rather, the phrase allows 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.

[0035] A general aspect of the present technology includes a structure for supporting an optical alignment member. The structure includes a frame that may include a plurality of sections joined together to provide a first support surface for engaging an aligner and a second support surface for engaging a shelf. The aligner is configured to provide a semi-enclosed open space for receiving the shelf that may include alignment features associated with a second optical component, and to guide a body of a first optical component from above onto the shelf to align with the second optical component via the alignment features. The plurality of sections may include: a bottom section that provides a front edge to the first support surface and a rear end to the second support surface; a pair of side sections that are spaced apart and joined to the two sides of the bottom section respectively from the front edge to the rear end; two shoulder sections that each have a lower end joined to the pair of side sections at an upward angle at the front edge; and a pair of arm sections that are joined to the upper ends of the two shoulder sections respectively to extend forward with the arm length parallel to the pair of side sections. The pair of arm sections is configured to be horizontally inserted into a package structure of the second optical component to place the frame in a floating state.

[0036] The embodiments may include one or more of the following features. The pair of arm segments may include a cylindrical shape having tapered ends for facilitating insertion into two holes in the encapsulation structure of the second optical component, respectively. The pair of arm segments are configured such that one arm segment fits into one of the two holes having a circular shape with a circumferential clearance of less than 30 μm, and the other arm segment fits into the other of the two holes having an oval shape with a vertical clearance of less than 30 μm and a horizontal clearance of less than 120 μm simultaneously. The two holes are spaced apart by a distance corresponding to the nominal spacing between the pair of side segments, which is configured to allow two aligners to be placed in the frame to respectively receive two shelves associated with two second optical components. The bottom segment may include a plurality of through holes configured to dispense epoxy from the lower side of the frame into the regions between the two aligners and the first support surface and between the two shelves and the second support surface. The structure may include two covers coupled to the frame via a pivot pin inserted into two holes in respective two shoulder segments. Each cover is configured to open independently in an upright position to expose the aligner placed in the frame or to close in a flat position to cover the aligner. The frame may further include a rear segment, which may include two outer struts respectively connected to the pair of side segments and a central strut connected to the bottom segment at the midpoint of the rear end of the first support surface. Each of the two outer struts has an inclined outer wall with an inward step, which is configured to form a latch for locking the corresponding one of the two covers in the closed position. The rear segment is configured to provide two open channels between the central strut and the two outer struts for transmitting ribbon optical fibers respectively associated with two first optical components. The rear segment is configured to provide a vertical clearance between each of the two covers in the closed position and each strut. The vertical clearance is configured to limit the overtravel of the cover to 0.5 mm for unlocking from the closed position, wherein the cover may include a plate attached to the lower side of the cover at a downwardly inclined angle, and the plate applies a limited force on the body of the first optical component to ensure optical alignment when the cover is locked in the closed position. The pair of arm segments are characterized by a stiffness that supports a force of at least 100 Newtons applied to the rear segment of the frame.

[0037] Another general aspect includes an apparatus for supporting two fiber optic array unit (FAU) connectors aligned with corresponding lenses of a photonic integrated circuit (PIC). The apparatus further includes a frame having a pair of arm sections coupled to two side sections of a bottom section, the pair of arm sections configured to be inserted in parallel into a package structure associated with a PIC chip to place the frame in a floating state, the bottom section providing a first support surface to support two aligners respectively disposed along the two side sections from above, each aligner providing a semi-closed open space to receive a shelf extending from a side edge of the PIC chip, the shelf being characterized by alignment features associated with the lens of the PIC chip, the semi-closed open space allowing the body of the FAU connector to be loaded onto the shelf from above and aligned with the lens based on the alignment features.

[0038] The implementation may include one or more of the following features. The bottom section is configured to provide a second support surface for supporting the two shelves extending respectively from the side edges of the PIC chip. The bottom section may include a plurality of through holes configured to dispense epoxy from the underside of the frame to the areas between the two aligners and the first support surface and between the two shelves and the second support surface. The frame may further include a rear section connected to the pair of side sections and the bottom section. The rear section may include two outer struts and a central strut, thus providing two open channels for routing the ribbon optical fibers of the FAU connector. Each of the two outer struts may include an inclined outer wall having an inward step configured to form a latch for locking the cover in the closed position to cover the aligners, with a vertical gap maintained between the cover in the closed position and the top region of the strut. The vertical gap is configured to limit the overtravel of the cover to 0.5 mm for unlocking from the closed position, wherein the cover may include a plate attached to the underside of the cover at a downward angle, and the plate presses on the body of the FAU connector aligned with the lens of the PIC chip on the shelf. The frame may further include two shoulder sections configured to connect the two side sections to the pair of arm sections at upward angles respectively to position the pair of arm sections above and parallel to the two side sections. The two shoulder sections may include two holes serving as pivot points for inserting cylindrical pins designed to support the rotation of the cover between the upright open position and the closed position. The pair of arm sections are characterized by a stiffness to support a force of at least 100 Newtons applied to the rear section of the frame. The pair of arm sections may include a cylindrical shape with tapered ends having two holes for facilitating insertion into the package structure of the PIC chip respectively. One of the pair of arm sections fits circumferentially in one of the two holes with a nominal gap of less than 30 um. The other of the pair of arm sections fits simultaneously in the other of the two holes with a vertical gap of less than 30 um and a horizontal gap of less than 120 um.

[0039] Yet another general aspect includes a method for supporting alignment of a fiber array unit (FAU) connector with a photonic integrated circuit (PIC). The method further includes providing a frame having a bottom section coupled to two side sections, the two side sections each further extending upward to be coupled to a pair of arm sections at a position above but parallel to the two side sections. The method further includes inserting the pair of arm sections into two holes in a package structure of a PIC chip to place the frame in a floating state to provide one of a support surface for supporting two shelves in the bottom section. The bottom section may include a plurality of through holes configured to dispense epoxy for bonding the two shelves thereabove. Each shelf extends beyond a corresponding lens at a side edge of the PIC chip and is characterized by alignment features associated with the lens. The method further includes placing two aligners in the frame. Each aligner has a front rod positioned on a surface of the PIC chip, while having a bottom to be bonded by epoxy on the other of the support surfaces in the bottom section of the frame. Each aligner is configured to provide a semi-enclosed open space for receiving one of the two shelves, with a non-contact gap between the aligner and the one of the two shelves.

[0040] 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 separately and cohesively designed to provide different aspects of functionality, such as supporting, guiding, adjusting, restricting the alignment of an optical component with another optical component. For example, an aligner may be made of molded plastic or sheet metal formed by die casting, machining or stamping. The frame may be made of machined nickel-plated copper tungsten or metal injection molded copper tungsten or other robust 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. A shelf is referred to as a member protruding from a wall (or something having vertical side edges) and in this context is a structure extending from the bottom from a side edge of a package structure of a circuit chip. A preferred material may be glass, the same as the material of the connector body located above, for achieving a firm and reliable optical alignment.

[0041] Figure 2Perspective, top, and side views of a frame for supporting an optical aligner to ensure optical alignment of an FAU connector with a PIC chip according to an embodiment of the present technology. In an embodiment, the frame 200 is provided as a single piece made of a rigid material having a plurality of functional sections to provide a support surface for at least an optical aligner having alignment features to insert an FAU connector aligned with a lens of a PIC chip. In the perspective view (section A) of the figure, the frame 200 includes a bottom section 210 having a first support surface 211 connected to a second support surface 212. The bottom section 210 is also configured to have a plurality of through-holes 215 in both the first support surface 211 and the second support surface 212. These through-holes are made for facilitating epoxy dispensing and joint inspection from the underside of the frame 200. The bottom section 210 has its two sides respectively connected to a pair of side sections 220. The bottom section 210 terminates forward at the front edge of the second support surface 212 and backward at the rear end of the first support surface 211, and the rear end is connected to the rear section 250 of the frame 200. The frame 200 further includes two shoulder sections 230 having lower ends respectively connected to the pair of side sections 220 and extending upward, and upper ends respectively connected to a pair of arm sections 240 that further extend forward parallel to the pair of side sections 220. In an embodiment, the pair of arm sections 240 are configured to be inserted into the package structure 12 of the PIC chip (see Figure 1 ). The two shoulder sections 230 also include two holes 231 designed for inserting pivot pins to support a cover 300 (not shown here). The rear section 250 includes three struts: two outer struts 251 respectively connected to the pair of side sections 220 and one central strut 252 located at the midpoint of the rear end and connected to the rear end of the first support surface 211. The outer strut 251 has an inclined sidewall 255 that slopes downward to an inward step 256. This shaped configuration of the inclined sidewall and the inward step is configured to form a latch for locking the cover 300 (see Figure 1 ). The central strut 252 has two sidewalls in a straight shape. The three-strut structure of the rear section 250 creates two channels (spacing d3) between the central strut 252 and either of the two outer struts 251, which provides a path for the ribbon optical fiber of the FAU connector (see Figure 1 ).

[0042] In the embodiment shown in section B of the figure, the top view of the frame 200 illustrates the spacing d1 between the pair of arm sections 240. Each of the two arm sections 240 has a tapered end 241 designed to facilitate attaching the frame 200 to the package structure 12. The spacing d1 is approximately the nominal spacing d2 between the two side sections, which is designed to allow two optical aligners 100 to be placed in the frame 200 (seeFigure 1 )。Each of the two aligners 100 is designed to provide a semi-closed open space to receive the shelves 13 that extend out of the side edges of the PIC chip. Thus, the two shelves 13 can be accommodated within the two aligners 100 placed in the frame 200. The two aligners 100 are configured such that their bottoms are supported by the first support surface 211 (to be joined by epoxy resin). The two shelves 13 are configured to be supported by the second support surface 212 (to be joined by epoxy resin). The epoxy resin can be dispensed from the lower side of the frame 200 and cured after optical alignment between the loaded FAU connectors and the lenses at the side edges of each FAU connector and the lenses of the PIC chip.

[0043] In the embodiment shown in part C of the figure, the side view of the frame 200 also shows the tapered ends 241 of each arm section 240 for insertion into the package structure of the PIC chip. It can be seen that the shoulder section 230 connects the arm section 240 at the upper end to the side section 220 at the lower end at an approximate 45-degree angle. When the arm section 240 is horizontally inserted into the package structure, the side section 220 (along with the bottom section not visible in the side view) will also be in a horizontal direction to keep the support surface flat.

[0044] Figure 3 is a perspective view of a frame inserted into the package structure of a PIC chip coupled to two covers in a closed position according to an embodiment of the present technology. In the embodiment, Figure 3 shows the two arm sections 240 respectively inserted into the two holes 125 and 125' in the package structure 12 (partially shown). The two arm sections 240 have a nominal cylindrical shape, while the two holes 125 and 125' have a nominal circular shape. In a specific embodiment, one of the two holes 125 can be intentionally made slightly different in shape from the other hole 125'. The tapered ends 241 allow the insertion operation to be relatively easier. The insertion of the arm sections into the holes is only an attachment support for the frame, which results in a floating state of the frame to keep the support surface flat in the horizontal direction. The floating state of the frame 200 helps to minimize the influence of the thermal expansion of nearby materials on the aligners 100 and the shelves 13 supported (or to be joined by epoxy resin) by the frame. Figure 3 also shows the two covers 300 coupled to the two shoulder sections 230 via a single pivot pin 305 inserted into the two holes 231. The pivot pin 305 allows the covers 300 to rotate from the closed position (currently shown as visible from the top side in Figure 3 to the upright open position (see Figure 1 ) to allow the two aligners 100 to be placed into each frame 200. The cover 300 includes a first plate 301 formed on one side of the cover 300 and a second plate 302 formed on the other side of the cover 300. As Figure 3As shown, the first plate 301 has a hook-shaped end configured to mate with the inward step 256 on the outer strut 251 when the cover 300 is in the closed position. The second plate 302 has a straight shape to slide down along the straight side of the central strut 252. The two covers are configured in a mirror-symmetric manner, except that the straight plate 302 is relatively displaced to clamp the central strut 252 at the opposite sides of the central strut 252.

[0045] Figure 4 is a cross-sectional view of two holes in a package structure of a PIC chip according to an embodiment of the present technology and an enlarged view showing the specific shapes of the two holes. In the embodiment, Figure 4 shows a further detailed configuration of the attachment of the arm section to the corresponding holes in the package structure 12 of the PIC chip. As shown is a cross-sectional view of two holes having a nominal circular shape with a spacing d1 respectively mating with two arm sections 240 having a cylindrical shape. In the enlarged view, the hole 125 is made in a circular shape, and so is the corresponding arm section 240, except that the diameter of the hole is slightly larger than the diameter of the arm section by a small gap g1 around the arm section 240. In the embodiment, the gap g1 allows the arm section 240 to be freely inserted or retrieved, but it is limited to a small spacing (e.g., nominal 30um) to minimize its movement (both lateral and vertical) within the hole 125 in the case of tight X / Y alignment. While the other hole 125' in the two holes is configured to be elliptical in shape to provide another arm section 240 having the same cylindrical shape within the hole 125', with a larger gap g2 in the horizontal direction but the same gap g1 in the vertical direction. This is to allow some margin for easier fabrication of the holes and the arm sections of the frame. At the same time, after the arm section is inserted into the hole, the elliptical shape of the hole restricts the rotation of the frame. The larger lateral gap (e.g., 120um) permits the two arm sections to have additional degrees of freedom to find their corresponding holes to complete the attachment. However, the same tight vertical gap (e.g., 30um or less) still provides the desired restriction to constrain the vertical swing of the frame, thus keeping the frame and the corresponding support surface in a floating state in the horizontal direction.

[0046] Figure 5Is a side view of the frame in the insertion package structure according to an embodiment of the present technology, which illustrates the floating state of the frame. It further shows in detail the frame attached to the package structure 12 in the floating state. The arm section 240 with the tapered end 241 has been inserted into the hole 125 in the horizontal direction, so that the side section 220 parallel to the arm section 240 is also in the horizontal direction. In this configuration, the arm section 240 has at least one contact position 120 at the bottom of the entrance of the hole 125, but there can be multiple contact points along the arm length, because the gap g1 between the hole 125 and the outer body of the cylindrical arm section 240 is very tight (less than 30um). When there is any force 410 (minimizing the weight of the frame itself) pressing on the rear section 250 of the frame or on the shelf 13 supported by the frame (by loading the FAU connector on it), this force 410 will be balanced by the reaction force from the package structure 12 at the contact point 420 near the front end of the arm section 240. The contact position 120 acts as the pivot point for this balance of the frame. Except for the pivot point 120 and the reaction force point 420, there is no other direct contact between the frame and the package structure 12, which implies that the associated support surface provided by the frame is maintained in a floating state to support the aligner and the shelf.

[0047] Reference Figure 5 , which also illustrates a side view of the cover 300 in the closed position on top of the frame. The cover 300 is coupled to the frame via pivot cylindrical pins 305 inserted into the holes 231 in the two shoulder sections 230 (see Figure 3 ). Optionally, as shown in Figure 3 , two covers 300 are coupled via a single pivot cylindrical pin 305 inserted into the corresponding holes in the two shoulder sections 230 of each frame 200. A sheet 303 is attached to the lower side of the cover 300 at a downward angle, so that when the cover 300 rotates to the closed position, this sheet 303 will contact the top surface of the body of the FAU connector 14 loaded on the shelf 13 via the aligner 100 (see Figure 1 ), and apply a force to hold the FAU connector 14 in the aligned position on its shelf (supported by the frame 200).

[0048] In a general aspect of the present technology, the frame 200 disclosed throughout the specification herein is for providing support for an alignment structure that assists in the alignment between the lens of the FAU connector and the corresponding lens of the PIC chip. Figure 6 Shows a perspective view of the body of the FAU connector used for aligning with the PIC chip to establish optical IO via the aligner 100 placed in the frame 200. Figure 6 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 6 Part B of Figure 1 shows alignment features associated with the present technology: two alignment rods 145 attached to corresponding V-shaped grooves in the bottom surface located near and parallel to both sides of the body 14. When loading the body of the FAU connector 14, the aligner 100 is configured to guide 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 alignment features pre-built in the shelf and extend from the encapsulation structure beyond the corresponding side edges of the PIC chip (see

[0049] Figure 7 ) to the lens of the optical IO at the side edge of the PIC chip where the shelf below the PIC chip is pre-aligned. Figure 6 is a perspective view of a configuration according to an embodiment of 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 the same configuration next to said configuration but in which the FAU connector 14 is placed on the shelf 13 by the same aligner. In the embodiment, the aligner is a part of an optical connector for a photon integrated circuit (PIC) chip (e.g., a silicon photonics-based IC with optical input / output co-packaged with an electronic switch IC). As shown, the aligners 100 are arranged in pairs in the frame 200, located at positions designated for the optical IOs at the side edges of the PIC chip. When each of the pair of aligners 100 is placed in the frame 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 flat state. At the same time, the shelf 13 extending from the side edge of the PIC chip is completely received within the semi-closed open space provided by one of the pair of aligners 100. The aligner 100 is in the proper position relative to the frame 200, i.e., designed to guide the body of the FAU connector 14 downward onto the shelf 13. The shelf 13 includes a pair of V-shaped grooves 135 (only one visible in this perspective view) formed along both sides of the shelf in the surface. In the embodiment, the shelf 13 is configured to serve as a support for the body of the FAU connector 14 loaded from the top, as illustrated in the adjacent one of the pair of aligners 100. The V-shaped grooves 135 in the shelf 13 are configured to receive the alignment rods (labeled 145 in

[0050] In an embodiment, the aligner 100 is placed in a proper position within the frame 200 such that the shelf 13 is fully received into the aligner with a surrounding gap and 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 may be glued to the bottom surface of the frame structure 200 by epoxy resin to ensure this proper position, while the frame 200 is configured to be attached to the robust encapsulation structure 12 of the CPO-PIC assembly (see Figure 1 and Figure 5 ) in a floating state. In another embodiment, once optical alignment is achieved after loading the body of the FAU connector 14 downward onto the shelf 13, the bottom of the shelf 13 can be glued to the bottom surface of the frame structure 200 by applying epoxy resin through a plurality of through-holes at the bottom section 210 from the lower side of the frame 200.

[0051] In yet another embodiment, the alignment structure (referred to as the aligner 100) of the present technology is placed in a designated position defined by the frame 200 based on the position of the optical I / O at the side edge of the PIC chip. In a specific embodiment, as Figure 8 shown, for each frame 200, two positions are provided for placing two aligners 100 adjacent 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. The shelf having corresponding alignment features associated with this lens is attached to the lower side of the encapsulation structure of the PIC chip and extends out of the side edge. The frame 200 is attached to the encapsulation structure 12 designed to encapsulate the CPO-PIC assembly (see Figure 1 ) along the side edge of the PIC chip such that two shelves are included within the frame 200. Then, each of the two aligners 100 is placed in the corresponding one of the 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 Figure 6 shown) onto the shelf to achieve alignment between the lens of the FAU connector and the corresponding lens of the PIC chip for forming one optical I / O of the CPO-PIC assembly.

[0052] In yet another embodiment, Figure 8 it is also shown that the formation of the optical I / O of the CPO-PIC assembly involves another feature part: a cover 300 for covering each aligner 100 in a designated position in the case of loading the body of the FAU connector 14. As Figure 8 shown, the cover 300 is coupled to the frame 200 via a pivot pin 305, which allows the cover 300 to open to an upright position or close to a flat position above the aligner 100 and the body of the FAU connector 14 loaded within the semi-closed open space of the aligner. Figure 8Shows the open position of the cover 300, revealing the sheet 303 connected to the bottom surface of the cover 300 at a downwardly inclined angle (but < 90°) (see Figure 5 ). In addition, the cover 300 is configured to have two additional sheets 301 and 302 connected to two side edges of the cover 300 at 90°. One sheet 302 is in a straight shape for sliding down along the straight side wall of the central pillar 252 on the frame 200 when the cover 300 is rotated to the closed state. The other sheet 301 has a hooked end for locking with the inward step 256 of the outer pillar 251 on the frame 200 when the cover 300 is in the closed state. This is shown in Figure 9 as the case when the cover 300 is rotated from the open position to the closed position via the pivot pin 305 to cover the aligner 100, and the inclined sheet 303 can be configured to press on the top of the body of the FAU connector 14 with spring force (see Figure 5 ) to ensure the alignment position for the alignment of the FAU connector with the lens of the PIC chip.

[0053] In an alternative aspect, the present technology provides a method for supporting the alignment of optical input / output (IO) of a co-packaged optical device - photonic integrated circuit (CPO - PIC) assembly. Figure 10 Shows a flowchart of a method 900 for supporting the alignment of a fiber array unit (FAU) connector with a photonic integrated circuit (PIC) in an embodiment of the present technology. The method 900 includes a step 910 of providing a frame having a bottom section connected to two side sections, and the two side sections further extend upwardly to be connected to a pair of arm sections respectively. The frame is a single irregularly shaped part composed of multiple sections. The function of each section is to jointly provide a support surface for supporting other parts to assist in forming optical input / output (IO) and optical alignment in the CPO - PIC assembly. For example, a silicon-based photonic integrated optical transceiver co-packaged with an electrical switch module in a CPO - PIC assembly needs to involve placing a micro-optical connector with a firm optical alignment for the optical IO. The FAU connector is used to form such an optical IO by coupling the lens of the FAU connector with the lens at the side edge of the PIC chip. In a specific embodiment, the frame is configured to provide a first support surface for engaging the aligner and a second support surface for engaging the shelf. The aligner is configured to guide the body of the FAU connector from the top to the shelf and find the alignment position there to achieve the alignment between the lens of the FAU connector and the corresponding lens of the PIC chip.

[0054] In an embodiment, method 900 further includes step 920 for inserting the pair of arm segments into two holes in the package structure of the PIC chip to place the frame in a floating state to provide one of the support surfaces for supporting two shelves in the bottom segment. In an embodiment, the arm segments, which are the parts of the frame that extend to the very front of the frame, are the only parts of the frame directly attached to the package structure. The two holes in the package structure are designed to fit the pair of arm segments having a cylindrical shape and to constrain their rotational and vertical movements, but leave a small degree of freedom for horizontal displacement in only one hole to facilitate the installation process. The arm segments are also parallel to the side segments and the bottom surface such that the frame is attached in a floating state to keep the support surface provided in the bottom segment maintained in a horizontal direction. In an embodiment, the frame is configured to have one support surface for supporting two shelves located in pairs at the side edges of the PIC chip. Each shelf is a part having alignment features associated with the lens of the PIC chip at the side edge. Optionally, the shelf is attached to a part of the lower side package structure of the PIC chip and extends beyond the lens at the side edge of the PIC chip by a small length.

[0055] Figure 10 Method 900 is also shown to include step 930 for placing two aligners in the frame. In an embodiment, each aligner consists of a front segment and a bottom segment that are respectively connected to two side segments spaced apart by a first distance to provide a semi-closed open space. The semi-closed open space further includes a cutout space from a part of the bottom segment and a part of the front segment. When the aligner is placed in the frame, the cutout space receives the shelf of the PIC chip, where the front segment of the aligner is positioned on the surface of the PIC chip and the bottom segment is supported by one of the support surfaces of the frame. In an embodiment, the aligner is placed in such a way that there is a non-contact gap between the aligner and the shelf received in the cutout space. In an embodiment, the bottom segment of the aligner is configured to be joined to one of the support surfaces of the frame by epoxy resin. In an embodiment, the aligner is manually placed into the frame by an operator or assembler into a position supported by the frame. In this position, the aligner can be used to facilitate the placement of the body of the FAU connector and to allow the lens of the FAU connector to be aligned with the lens at the side edge of the PIC chip. The functions and other benefits of the frame have been presented in the previous paragraphs and are described from Figures 1 to 9 as follows.

[0056] In another embodiment, method 900 may include steps for using two aligners in a frame to guide two FAU connectors to two shelves respectively in a corresponding semi-closed open space. In an embodiment, the aligners are configured to provide certain functional sections for loading the FAU connectors. For example, the aligner may include inclined facets to its side sections for facilitating the lowering of the body of the FAU connector from the top down onto the shelf. The width of the open space is set to be slightly larger than the width of the body of the FAU connector.

[0057] In yet another embodiment, method 900 may include steps for adjusting each FAU connector on the shelf based on alignment features to achieve alignment between the lens of the FAU connector and the corresponding lens at the side edge of the PIC chip. In an embodiment, the aligner may be configured to provide additional rotational degrees of freedom within the semi-closed open space for facilitating the adjustment of the body of the FAU connector to find the alignment position based on alignment features (e.g., by matching two alignment rods with corresponding V-shaped grooves). The aligner may further be configured to set a front L-shaped end section to provide a hard stop for the body of the FAU connector to prevent physical contact between the lens of the FAU connector and the lens of the PIC chip, instead maintaining an ideal spacing to maximize optical coupling. Alternatively, the aligner may also be configured to set a rear L-shaped end section to provide additional translational degrees of freedom for adjusting the FAU connector within the semi-closed open space.

[0058] In yet another embodiment, method 900 may further include steps for curing the epoxy resin between each shelf and one of the support surfaces to fix the shelf and the body of the upper FAU connector in the alignment position. As in step 920, once the frame (its two arm sections) is inserted into the package structure of the PIC chip, the shelf will be supported by one of the support surfaces provided by the frame. However, the support is not fixedly engaged, and the support surface is flat and in a floating state. In an embodiment, the bottom section of the support surface provided contains a plurality of through holes therein. Using these through holes, the epoxy resin can be dispensed from the lower side of the bottom section into the interface between the shelf and the support surface without curing. Only after loading the FAU connector onto the shelf via the aligner and achieving optical alignment between the FAU connector and the PIC chip, step 920 is performed to bond the shelf to the support surface to ensure alignment between the lens of the FAU connector and the lens of the PIC chip.

[0059] In a further embodiment, method 900 may further include the step of 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 930, 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 not fixedly engaged, and the support surface provided by the frame is flat and in a floating state. The function of the aligner is to guide the body of the FAU connector into the semi-enclosed open space and find its alignment position on the shelf. Once this alignment position is reached, the shelf can be fixed to the frame first by curing the epoxy resin between the shelf and the frame. Then, the aligner can be fixed by curing the epoxy resin in the interface between the support surface and the bottom of the aligner to fix the support position of the aligner on the support surface of the frame. This position will correspond to the ideal position for maintaining a non-contact gap between the aligner and the shelf and the body of the FAU connector located above the shelf. Moreover, the epoxy resin can be pre-applied through a plurality of through holes into the interface between the bottom section of the aligner and the support surface of the frame. Stress measurements indicate that little stress is exhibited in the optical I / O involving these parts (such as the frame, aligner, and shelf) that are subjected to a temperature change from 150 °C to 80 °C based on the present disclosure.

[0060] In some embodiments, method 900 includes placing two aligners having the same structure into the frame in a side-by-side configuration. The two aligners will be joined to one of the support surfaces of the frame by epoxy resin to fix the corresponding positions with a pair of corresponding shelves with a non-contact gap.

[0061] In another embodiment, the frame may be associated with a cover coupled to two shoulder sections. Optionally, there are two covers that are side by side and are commonly coupled to the two shoulder sections via a single pivot pin. Method 900 may include opening the two covers to an upright position to make the bottom section of the frame available for placing two aligners. Additionally, method 900 may include closing the two covers to a flat position to lock the covers to the closed position by using a sheet plate having a hooked end at one side of each cover to lock with an inward step on the outer strut. Method 900 may further include using an inclined sheet plate attached to the lower side of the cover to apply a force for holding the FAU connector on the shelf and aligning it with the PIC chip.

[0062] 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 defined by the appended claims.

Claims

1. A structure for supporting an optical alignment member, comprising: a frame comprising a plurality of sections coupled together to provide a first support surface for engaging an aligner and a second support surface for engaging a shelf, the aligner being configured to provide a semi-enclosed open space for receiving the shelf including an alignment feature associated with a second optical component, and guiding a body of a first optical component from a top onto the shelf to be aligned with the second optical component via the alignment feature, the plurality of sections comprising: a bottom section providing a front edge to the first support surface and a rear end to the second support surface; a pair of side sections, which are spaced apart and respectively connected to two sides of the bottom section from the front edge to the rear end; two shoulder sections each having a lower end connected to the pair of side sections at an upward angle at the front edge; and A pair of arm sections are respectively connected to the upper ends of the two shoulder sections so that the arm lengths extend forward in parallel with the pair of side sections, and the pair of arm sections are configured to be horizontally inserted into the packaging structure of the second optical component so that the frame is in a floating state. 2 . The structure of claim 1 , wherein the pair of arm segments comprises a cylindrical shape with tapered ends for facilitating insertion into two holes in the packaging structure of the second optical component, respectively.

3. The structure according to claim 2, wherein the pair of arm segments are configured so that one arm segment fits in one of the circular shapes of the two holes with a circumferential gap of less than 30um, and so that the other arm segment fits in the other of the elliptical shapes of the two holes with a vertical gap of less than 30um and a horizontal gap of less than 120um at the same time.

4. The structure of claim 2, wherein the two holes are spaced apart by a distance corresponding to a nominal spacing between the pair of side segments, the nominal spacing being configured to allow two aligners to be placed in the frame to respectively receive two shelves associated with two second optical components.

5. The structure of claim 1 , further comprising two covers coupled to the frame via a pivot pin inserted into two holes in corresponding two shoulder sections, each cover being configured to independently open in an upright position to expose the aligner placed in the frame or to close in a flat position to cover the aligner.

6. A structure according to claim 5, wherein the frame further includes a rear section, the rear section including two outer pillars respectively connected to the pair of side sections and a center pillar connected to the bottom section at the midpoint of the rear end of the first support surface, each of the two outer pillars having an inclined outer side wall with an inward step, the inward step being configured to form a latch for locking the corresponding one of the two covers in a flat closed position.

7. A structure according to claim 6, wherein the rear section is configured to provide two open channels between the central pillar and the two outer pillars for transmitting ribbon optical fibers respectively associated with two first optical components, and to provide a vertical gap between each of the two covers in the flat closed position and each pillar.

8. The structure of claim 7 wherein the vertical gap is configured to limit the cover to an overtravel of 0.5 mm for unlocking from the flat closed position, wherein the cover includes a plate attached to an underside of the cover at a downwardly inclined angle, the plate applying a limited force on the body of the first optical component to ensure optical alignment when the cover is locked in the flat closed position.

9. The structure of claim 6, wherein the pair of arm sections are characterized by a stiffness to support a force of at least 100 Newtons applied to the rear section of the frame.

10. The structure of claim 4, wherein the bottom section includes a plurality of through holes configured to dispense epoxy from an underside of the frame to areas between the two aligners and the first support surface and between the two shelves and the second support surface.

11. An apparatus for supporting two fiber array unit (FAU) connectors aligned with respective lenses of a photonic integrated circuit (PIC), comprising: A frame having a pair of arm sections connected to two side sections of a bottom section, the pair of arm sections being configured to be inserted in parallel into a packaging structure associated with a PIC chip so that the frame is in a floating state, the bottom section providing a first supporting surface to support two aligners respectively disposed from the top along the two side sections, each aligner providing a semi-enclosed open space to receive a shelf extending from a side edge of the PIC chip, the shelf being characterized by an alignment feature associated with a lens of the PIC chip, the semi-enclosed open space allowing a body of a FAU connector to be loaded onto the shelf from the top and aligned with the lens based on the alignment feature.

12. The apparatus of claim 11, wherein the bottom section is configured to provide a second support surface to support the two shelves respectively extending from the side edges of the PIC chip.

13. The apparatus of claim 12, wherein the bottom section includes a plurality of through holes configured to dispense epoxy from an underside of the frame to areas between the two aligners and the first support surface and between the two shelves and the second support surface.

14. The apparatus of claim 11, wherein the frame further comprises a rear section connected to the pair of side sections and the bottom section, the rear section comprising two outer pillars and one center pillar, thereby providing two open channels for passing the ribbon optical fibers of the FAU connector.

15. The apparatus of claim 14, wherein each of the two outer pillars comprises an inclined outer sidewall having an inward step configured to form a latch for locking a cover in a flat closed position covering the aligner to maintain a vertical gap between the cover in the flat closed position and a top region of the pillar.

16. An apparatus according to claim 15, wherein the vertical gap is configured to limit the cover to an overtravel of 0.5 mm for unlocking from the flat closed position, wherein the cover includes a tab attached to the underside of the cover at a downward angle, the tab pressing on the body of the FAU connector on the shelf aligned with the lens of the PIC chip.

17. An apparatus according to claim 15, wherein the frame further includes two shoulder sections configured to connect the two side sections with the pair of arm sections at an upward angle respectively so that the pair of arm sections are positioned higher than and parallel to the two side sections, and the two shoulder sections include two holes as pivot points for inserting a cylindrical pin designed to support the cover to rotate between the upright open position and the flat closed position.

18. The apparatus of claim 11, wherein the pair of arm segments comprises a cylindrical shape with a tapered end for facilitating insertion into two holes in the package structure of the PIC chip, respectively, one of the pair of arm segments fits circumferentially in one of the two holes with a nominal gap of less than 30 um, and the other of the pair of arm segments fits in the other of the two holes simultaneously with a vertical gap of less than 30 um and a horizontal gap of less than 120 um.

19. The apparatus of claim 14, wherein the pair of arm sections are characterized by a stiffness to support a force of at least 100 Newtons applied to the rear section of the frame.

20. A method for supporting alignment of a fiber array unit (FAU) connector with a photonic integrated circuit (PIC), comprising: providing a frame having a bottom section connected to two side sections, the two side sections respectively extending further upward to be connected to a pair of arm sections at a position higher than but parallel to the two side sections; The pair of arm sections are inserted into two holes in the packaging structure of the PIC chip to place the frame in a floating state to provide one of the support surfaces for supporting two shelves in the bottom section, the bottom section including a plurality of through holes configured to dispense epoxy resin for bonding the two shelves above, each shelf extending beyond the lens at the side edge of the PIC chip and characterized in that an alignment feature associated with the lens; and Two aligners are placed in the frame, each aligner having a front bar positioned on the surface of the PIC chip and having a bottom to be joined by epoxy resin positioned on the other of the support surfaces in the bottom section of the frame, each aligner being configured to provide a semi-enclosed open space for receiving one of the two shelves without a contact gap.

Images