Detachable optical coupler with an enlarged beam

Abstract

A detachable optical coupler having an expanded beam is provided. [Solution] The optical coupler enables communication with a PIC (photonic integrated circuit). The optical coupler is manufactured on a wafer scale and provides a detachable coupling to an array of optical fibers. Angled reflectors at the ends of the optical channels enable perpendicular coupling to or from the PIC. The optical beam is magnified by a lens at the interface to increase the matching tolerance.

Description

TECHNICAL FIELD

[0001] A detachable optical coupler with an expanded beam is provided.

BACKGROUND ART

[0002] With the expansion of data bandwidth, the demand for computing capability is escalating in various fields such as data centers, as well as high-performance computing for artificial intelligence (AI) and machine learning (ML) applications, for example. This trend poses significant challenges to the advancement of next-generation computing technologies. In response to this challenge, the advent of Co-Packaged Optics (CPO) provides a promising solution. CPO directly integrates optical modules with electrical dies on the same package, avoiding conventional approaches that use separate pluggable modules. CPO seamlessly combines the high-performance computing power of EICs (Electric Integrated Circuits) including CPUs and / or GPUs with the high-bandwidth, low-power advantages of PIC (Photonic Integrated Circuit) modules for data transmission and switching. By integrating electrical and photonic components into a single monolithic package, CPO facilitates a significant leap toward achieving extremely large-scale computing capabilities for next-generation technologies.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings.

[0004] [Figure 1] FIG. 2 shows a cross-sectional view of a vertical optical coupler according to various embodiments.

[0005] [Figure 2] FIG. 3 shows a top view of the vertical optical coupler of FIG. 1 according to various embodiments.

[0006] [Figure 3] Cross-sectional views of the first detachable vertical optical coupler according to various embodiments are shown.

[0007] [Figure 4A] Figure 3 shows a first exemplary top view of a vertical optical coupler according to various embodiments. [Figure 4B] A second exemplary top view of the vertical optical coupler of Figure 3 having staggered optical channels according to various embodiments is shown.

[0008] [Figure 5A] The first cross-sectional view of the second detachable vertical optical coupler according to various embodiments is shown. [Figure 5B] A second cross-sectional view of the second detachable vertical optical coupler according to various embodiments is shown.

[0009] [Figure 6A] Figure 5 shows a first exemplary top view of the second vertical optical coupler according to various embodiments. [Figure 6B] Figure 5 shows a second exemplary top view of a second vertical optical coupler having staggered optical channels according to various embodiments.

[0010] [Figure 7] Cross-sectional views of the third detachable vertical optical coupler according to various embodiments are shown.

[0011] [Figure 8A] Figure 7 shows a first exemplary top view of the third vertical optical coupler according to various embodiments. [Figure 8B] Figure 7 shows a second exemplary top view of a third vertical optical coupler having staggered optical channels according to various embodiments.

[0012] [Figure 9A] Figures 1 to 8 show a cross-sectional view of an exemplary implementation of an angled reflective surface for use in any of the embodiments. [Figure 9B]Shows a cross-sectional view of an exemplary implementation of an angled reflective surface for use in any of the embodiments of Figures 1 to 8. [Figure 9C] Shows a cross-sectional view of an exemplary implementation of an angled reflective surface for use in any of the embodiments of Figures 1 to 8. [Figure 9D] Shows a cross-sectional view of an exemplary implementation of an angled reflective surface for use in any of the embodiments of Figures 1 to 8.

[0013] [Figure 10] Figure 3 is a cross-sectional view of an optical bridge interface based on evanescent coupling, in accordance with some various embodiments.

[0014] [Figure 11A] 2 is two exemplary detailed cross-sectional views of the optical bridge interface of Figure 10, in accordance with some various embodiments.

[0015] [Figure 11B] 2 is two exemplary detailed cross-sectional views of the optical bridge interface of Figure 10, in accordance with some various embodiments.

[0016] [Figure 12] FIG. 3 is an exemplary top view of the optical bridge interface of Figure 10, in accordance with some various embodiments.

[0017] [Figure 13] Figure 3 is an exemplary cross-sectional view of an optical coupler having stacked waveguides, in accordance with some various embodiments.

[0018] [Figure 14A] FIG. 3 is an exemplary detailed top view of the three-dimensional waveguide of Figure 13, in accordance with some various embodiments.

[0019] [Figure 14B] 2 is two cross-sectional views of the waveguide of Figure 14A, in accordance with some various embodiments.

[0020] [Figure 14C] Two cross-sectional views of the waveguide shown in Figure 14A, according to several different embodiments.

[0021] [Figure 15] This is an exemplary cross-sectional view of an optical coupler having stacked waveguides and reflectors according to several different embodiments.

[0022] [Figure 16] This is a top view of a wafer and die that may be included in a microelectronic package or photonic device that includes or is used with an optical coupler, according to one embodiment.

[0023] [Figure 17] This is a side cross-sectional view of an exemplary microelectronic package, which may include one or more optical couplers, according to one embodiment.

[0024] [Figure 18] This is a block diagram of a photonic device that may include one or more optical couplers according to one embodiment. [Modes for carrying out the invention]

[0025] The systems, methods, and devices of this disclosure each have several inventive embodiments, and no single embodiment alone may exclusively represent all of the desirable attributes disclosed herein. Details of one or more implementations of the subject matter described herein are provided in the following description and accompanying drawings.

[0026] For the purpose of illustrating the optical interface proposed in this specification, it may be useful to first understand the phenomena that may operate in the context of a CPO system. The following basic information can be considered a basis for adequately explaining this disclosure. Such information is provided for illustrative purposes only and should not be construed in any way to limit the broad scope and potential uses of this disclosure.

[0027] Metallic communication lines, such as copper or aluminum wires, have traditionally been used for communication within and between microelectronic devices. Metals are excellent electrical conductors, facilitating the transmission of electrical signals at very high speeds over short distances. Metallic interconnects are commonly used for on-chip communication and connecting transistors, logic gates, and other components within microchips. However, as microelectronics continue to shrink in size and increase in complexity, the limitations of metallic interconnects have become more apparent. These limitations include resistance, capacitance, and signal propagation delay, which can lead to problems with power consumption, heat generation, and signal integrity.

[0028] Optical communication provides an alternative to metal interconnects in microelectronics. Optical connections use light to transmit data within and between electronic components. Optical communication can address some of the limitations of metal interconnects and offer several advantages, including high-speed data transfer, immunity to electromagnetic interference, and lower power consumption.

[0029] In CPO systems, the optical I / O architecture plays a crucial role in determining the bandwidth of the CPO system. Firstly, the I / O architecture establishes the channel density, which defines the total number of channels within a given form factor. Secondly, it determines the spectral bandwidth of the optical signal, and it also determines the modulation state within each channel. However, conventional optical I / O architectures often exhibit a trade-off between high density and high bandwidth characteristics, which significantly limits the bandwidth capability of CPO solutions.

[0030] For major CPO products on the market, existing fiber-tip coupling solutions include edge coupling with V-groove structures and vertical coupling using grid couplers. Edge couplers offer the advantages of wide bandwidth and easy assembly, while vertical couplers based on grid couplers provide high channel density but have limited spectral width. Furthermore, both of these solutions require post-assembly mounting, which presents significant difficulties in alignment control and limits yield for scalable production.

[0031] In an edge coupler configuration, the optical signal from the PIC is transmitted through a spot size converter (SSC), such as an inverse taper, which magnifies small optical modes from the PIC waveguide to a size comparable to the beam size in the optical fiber (approximately 9-10 μm). To ensure a positional accuracy between the fiber and the SSC, typically within 1-2 μm, a V-shaped groove (V-groove) is etched onto the silicon substrate using lithography and anisotropic wet etching along the crystal orientation. The edge coupler architecture provides a simple assembly process because the fiber can be fixed onto wafer-level processed features integrated on the PIC. This advantage makes it the most widely used structure in conventional CPO products. Furthermore, since edge coupling is insensitive to optical wavelength, it can support a wide optical spectrum. However, a significant drawback of edge couplers is the limitation of channel density. In the edge coupler configuration, the channels are arranged in a 1D array. As the number of channels increases, the dimensions of the coupler increase, making it difficult to further improve the system's bandwidth and form factor.

[0032] In contrast, vertical coupler configurations have the opposite advantages and disadvantages compared to edge couplers. Lattice couplers, which include submicron periodic features, can receive optical beams from the vertical and couple them to transverse waveguides through diffraction effects. In vertical coupling, fibers can be arranged in a 2D array, which significantly improves channel density compared to a 1D array in edge coupling scenarios. However, lattice couplers also have significant drawbacks. Firstly, because lattice couplers operate based on diffraction effects, their efficiency is highly dependent on the optical wavelength, and as a result, they only operate in a narrow spectral band. Furthermore, the theoretical efficiency of lattice couplers is typically around 80%, resulting in higher losses than edge couplers. In addition, vertical coupling is also a much more complex assembly process because it cannot utilize integrated features on the PIC, such as V-grooves, for fiber alignment. Therefore, it is difficult for any of these conventional I / O solutions to simultaneously achieve high channel density and wide optical bandwidth.

[0033] This specification describes an I / O architecture for interconnecting optical fibers to a photonic integrated circuit (PIC) that simultaneously supports high channel density and wide optical bandwidth. The proposed architecture is compatible with wafer-level processes to provide high alignment accuracy and low cost for scalable manufacturing. Several architectures employ expanded beam technology to improve alignment tolerances, enable detachable couplers, and function as a user interface.

[0034] In some embodiments, the optical I / O architecture for CPO is based on vertical coupling. The vertical coupling configuration described herein achieves a high-density 2D channel array while still supporting a wide optical bandwidth, thereby providing significantly higher bandwidth capability compared to conventional CPO solutions. The vertical optical coupler can function as a detachable user interface by utilizing an expanded beam design.

[0035] In some embodiments, a lens on one portion of the vertical coupler (e.g., a detachable unit attached to an array of optical fibers) is positioned directly above the corresponding lens on the other side of the vertical coupler (e.g., a PIC). The lenses may be positioned perpendicularly above a mirror that reflects the incident horizontal optical signal vertically and passes through a stacked lens. In other embodiments, the fiber mounting portion of the vertical coupler may have a curved reflector that directs the vertical optical signal toward a horizontally mounted optical fiber. In yet another embodiment, a pair of lenses on the two sides of the vertical coupler may be arranged to provide a self-locking mechanism that can further increase the alignment tolerance of the vertical coupler.

[0036] As mentioned above, data transmission bandwidth is a critical performance metric for CPO products. In conventional CPO solutions, one of the main limitations on data bandwidth is the channel density resulting from the substantial dimensional mismatch between the optical fiber and the PIC waveguide. For PIC waveguides, a pitch distance of 5-10 μm is usually sufficient to avoid crosstalk between channels. However, standard optical fibers have significantly larger dimensions than PIC waveguides, typically with a diameter of 125 μm, which severely limits the maximum channel density of the PIC-fiber I / O interface. This either limits the bandwidth of current CPO products or necessitates a larger form factor.

[0037] In some embodiments, optical I / O architectures are disclosed that include two-stage pitch scaling capability based on evanescent coupling. This architecture can achieve channel densities more than 10 times higher than conventional I / O solutions, significantly improving the bandwidth capability of CPO products. The described flexible material-based couplers offer improved loss performance, flexibility, and stability compared to conventional glass-based couplers. These embodiments include optical bridges in which die-to-die optical connections enable the integration of optical modules with diverse functions. As with other embodiments, manufacturing can be achieved during wafer-level processing, which facilitates low-cost, scalable manufacturing.

[0038] In some embodiments, the 3D waveguide structure is bonded to the PIC at the wafer level with high precision. Evanescent coupling is used to communicate optical signals between the waveguides in the 3D waveguide structure and the silicon waveguides in the PIC. The waveguides in the 3D waveguide structure are arranged using multiple stacked waveguides to convert a 2D array of channels into a 3D array. This makes it possible to scale up the connection interface from a 1D array to a 2D array, thereby increasing the maximum number of optical channels in the interface between the PIC and the fiber array.

[0039] The following detailed description refers to the accompanying drawings that form part of this specification, where the same reference numerals throughout the drawings indicate the same parts, and the drawings illustrate possible embodiments. It should be understood that other embodiments may be used, and structural or logical modifications may be made without departing from the scope of the claimed subject matter. Therefore, the following detailed description should not be construed as restrictive.

[0040] Any feature described with reference to any of the accompanying drawings of this specification may be combined with any other features as necessary to form an optical coupler, a microelectronic package 2200, or a photonic device 2300, or a package containing one or more devices (e.g., a CPO system). Some elements of the drawings having the same reference numerals may be shared between different drawings. For ease of explanation, the descriptions of these elements provided with respect to one of the drawings are not repeated for the other drawings, and these elements may take the form of any of the embodiments disclosed herein. The drawings are not necessarily to scale. Some of the drawings show straight lines with flat walls / surfaces and right angles, but this is for ease of explanation only and may not reflect actual process limitations that may cause various features to not appear so "ideally" when any of the structures described herein are examined, for example, using scanning electron microscope (SEM) images or transmission electron microscope (TEM) images. In such images of the actual structure, possible processing defects, such as not-so-straight edges of the material, tapered vias or other openings, careless rounding of corners, or variations in the thickness of different material layers, may also be visible. Other defects common in the field of semiconductor device manufacturing and packaging, not described herein, may also be present. For example, inspection of layout and mask data for reconstructing the circuit using an optical microscope or transmission electron microscope, as well as reverse engineering of parts of the device, and / or inspection of cross-sections of the device for detecting the shape and position of various device elements described herein using, for example, physical failure analysis (PFA), may enable the determination of the presence of optical couplers as described herein.

[0041] For the purposes of this disclosure, the phrase "A and / or B" means (A), (B), or (A and B). For the purposes of this disclosure, the phrase "A, B, and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). When used to describe a range of dimensions, the phrase "between X and Y" means a range that includes X and Y. When used to describe the location of an element, the phrase "between X and Y" means a region that is spatially between element X and element Y. The terms "substantially," "near," "approximately," "close," and "about" generally mean within + / -20% of a target value, for example, within + / -5% or + / -2%, based on the context of a particular value as described in this specification or known in the art. Similarly, terms indicating the orientation of various elements, such as "coplanar," "perpendicular," "orthogonal," "parallel," or any other angle between elements, generally refer to being within + / - 10% of the exact orientation, for example, within + / - 5% or + / - 2%.

[0042] The descriptions use the phrases “in one embodiment” or “in one embodiment,” which may each refer to one or more of the same or different embodiments. Furthermore, terms such as “equipped with,” “includes,” and “having” as used in reference to embodiments of the disclosure are synonymous. As used in this specification, the terms “package” and “integrated circuit (IC) package” are synonymous, as are the terms “die” and “IC die.” Furthermore, the terms “chip,” “chiplet,” “die,” and “IC die” may be used interchangeably in this specification. In this specification, certain elements may be referred to singly, but such elements may include multiple sub-elements. For example, “insulating material” may include one or more insulating materials.

[0043] Figure 1 shows a 2D cross-sectional view of the vertical optical coupler 100. The vertical optical coupler 100 couples the PIC 140 with the Fiber Attached Unit (FAU) 150. On the PIC side, a reflecting surface 125 is used to deflect the beam 120 in order to enable vertical beam coupling without spectral width limitations. This differs from conventional vertical coupler configurations that use lattice coupling as described above. The reflecting surface 125 can be manufactured during a wafer-level process, for example, by generating an inclined surface for forming the reflecting surface 125 using grayscale lithography. Beam deflection can be achieved by either total internal reflection (TIR) ​​or high-reflection coating (HRC) along the inclined surface. For example, the reflecting surface 125 may include a low refractive index material such as air, or a highly reflective material such as aluminum.

[0044] On the FAU150 side, the monolithic fiber housing is manufactured using a 2D ferrule array to guide the optical fibers and bend them perpendicularly in their direction. The monolithic fiber housing can be processed based on multiple materials, such as laser-assisted etching on bulk glass or two-photon polymerization (2PP) 3D printing on polymer materials. The FAU150 is assembled with the PIC140 via physical surface contact using wafer bonding technology, for example, in a bonding layer containing bonding material 110. Thus, an optical I / O architecture supporting high density and broadband is fully achieved through wafer-level processes.

[0045] In the descriptions of Figures 1 to 15, some elements referred to by reference numerals are shown in different patterns in these figures, and the legend at the bottom of the page shows the correspondence between the reference numerals and the patterns. The legend indicates that Figure 1 uses different patterns to show the support structure 102, optical material 104, mirror 106, housing material 108, coupling material 110, and optical fiber 112.

[0046] Generally, embodiments of the present disclosure may be formed or executed on a support structure, for example, a support structure 102 shown in Figure 1. The support structure 102 may be, for example, a substrate, die, wafer, or chip. For example, the support structure 102 may be the wafer 2100 in Figure 16A described below, or a die, for example, the segmented die 2102 in Figure 16B described below, or may be included in a die. The support structure 102 extends along the xy plane of the coordinate system shown in Figure 1.

[0047] In some embodiments, the support structure 102 may be a substrate containing silicon and / or hafnium. More generally, the support structure may be a semiconductor substrate composed of a semiconductor material system, for example, an N-type or P-type material system. In one embodiment, the semiconductor substrate may be a crystalline substrate formed using bulk silicon or silicon-on-insulator (SOI) substrates. In other embodiments, the semiconductor substrate may be formed using alternative materials, which may or may not be combined with silicon, and which include, but are not limited to, germanium, silicon germanium, indium antimony, lead telluride, indium arsenide, indium phosphide, gallium arsenide, aluminum gallium arsenide, aluminum arsenide, indium aluminum arsenide, aluminum indium antimony, indium gallium arsenide, gallium nitride, indium gallium nitride, aluminum indium nitride, or gallium antimony, or other combinations of Group III-V materials (i.e., materials from Group III and V of the periodic system of elements), Group II-VI materials (i.e., materials from Group II and IV of the periodic system of elements), or Group IV materials (i.e., materials from Group IV of the periodic system of elements). In some embodiments, the substrate may be amorphous. In some embodiments, the support structure is a printed circuit board (printed The substrate may be a circuit board (PCB). While several examples of materials on which the substrate can be formed are described in this specification, any material that can serve as a base on which an optical coupler, for example, a PIC having an optical coupler as described in this specification, can be constructed falls within the spirit and scope of this disclosure.

[0048] The optical material 104 rests on the support structure 102. The optical material 104 provides one or more optical channels, for example, an optical channel for the beam 120 as shown in Figure 1. The optical material 104 may be within an optical layer 160 containing one or more waveguides for transmitting optical signals. Each optical layer 160 may contain one or more other materials that form the boundary of the waveguide and prevent leakage of optical signals from the waveguide, such materials may be called cladding or separation materials. Multiple separation materials may be used along different edges or portions of the waveguide. For example, a waveguide having a rectangular cross-section may be formed on a first separation layer, so that the bottom surface of the waveguide is coupled to the first separation layer. A second separation material may be deposited on top of the waveguide such that the second separation layer surrounds the sides and top surface of the waveguide.

[0049] The optical material 104 (also called the waveguide material) within the waveguide has a uniform crystalline structure that allows light waves to propagate through the waveguide material with minimal loss. For example, the waveguide material may have a particle size of at least 5 nanometers. In some embodiments, the waveguide material has a larger minimum particle size, for example, a particle size of at least 50 nanometers, or a particle size of at least 100 nanometers. The waveguide may be formed from any suitable single-crystal material such as sapphire, quartz, silicon, silicon compounds (e.g., silicon oxide or silicon nitride), indium phosphide, germanium or germanium alloys, gallium, arsenic (e.g., arsenic III compounds in which arsenic III is combined with another element such as boron, aluminum, gallium, or indium), or any III-V material (i.e., materials from groups III and V of the periodic system of elements).

[0050] The separation material is a material that does not have optical properties, or a material that has optical properties different from those of the waveguide. For example, the separation material may include polycrystalline or amorphous silicon, or silicon compounds such as silicon dioxide or silicon nitride. In some embodiments, the separation material is a single-crystal material that has optical properties different from those of the waveguide, for example, a single-crystal material with a higher refractive index than that of the waveguide (e.g., single-crystal silicon, gallium arsenide, or any of the other single-crystal materials mentioned above). In some embodiments, multiple separation layers are formed from two or more different separation materials.

[0051] In some embodiments, the waveguide material has a refractive index between 1.3 and 4. The isolation material adjacent to at least a portion of the waveguide may have a different refractive index between 1.3 and 4. The waveguide material and the isolation material may be selected such that the isolation material has a refractive index much higher or much lower than that of the waveguide material. In some embodiments, the isolation material and the waveguide material may have similar or the same refractive index. In such embodiments, the interface between the waveguide material and the isolation material can prevent signal leakage to the isolation material, for example, if the crystal structures of the waveguide material and the isolation material are different, or if the crystal structures restart at the interface (for example, if the isolation material and the waveguide material grow separately).

[0052] In some embodiments, the optical layer 160 further includes photonic components for manipulating optical signals, such as gain chips, diffraction gratings, combiners, and demodulators. The photonic components may include any of the waveguide materials described above. In some embodiments, the optical layer 160 may also include electro-optic components, such as electro-optic modulators, including Mach-Zehnder modulators or ring oscillators.

[0053] The optical material 104 includes an optical channel extending in a first direction, which in this example is represented by a beam 120 and extends in the x-direction. The path of the beam 120 is parallel to the plane of the support structure 102. At the end of the optical channel, the beam 120 is incident on a reflector, such as a mirror 106. The mirror 106 has a reflecting surface 125 that is angled with respect to the first direction, such as the x-direction. In the illustrated example, the reflecting surface 125 is at an angle of about 45° with respect to the x-direction. In other examples, the reflecting surface 125 may be angled, for example, between 30° and 60° with respect to the x-direction, or by a different amount. The reflecting surface is neither parallel nor perpendicular to the direction of the incident beam 120.

[0054] The mirror 106 may have different structures behind its angled surface. Figures 9A to 9D, described below, show several different arrangements of the mirror 106 that may be manufactured using different manufacturing processes. The reflective surface 125 may be a high-reflection coating (HRC) covering the inclined surface of the mirror 106. Alternatively, the mirror 106 may be a total internal reflection (TIR) ​​reflector.

[0055] As described above, the FAU150 is bonded to the PIC140, particularly to the optical layer 160. The bonding material 110 may be an adhesive that ensures the FAU150 and PIC140 are attached to each other. The bonding material 110 allows the reflected beam 122 to pass from the reflective surface 125 to the FAU150.

[0056] FAU150 includes a housing material 108 which may be, for example, a glass material, a polymer material, or another suitable material for holding the optical fiber 135. The end of the optical fiber 135 is positioned to receive the reflected beam 122. In this example, the reflected beam 122 extends through a small portion of the housing material 108, and in such embodiments, the housing material 108 allows the transmission of the reflected beam 122 to the end of the optical fiber 135. In other embodiments, the optical fiber 135 extends to a coupling material 110, and the housing material 108 may or may not allow the transmission of optical signals.

[0057] The optical fiber 135 is bent within the FAU 150, and the vent 130 is directly above the end of the optical fiber 135 that receives the reflected beam 122. The optical fiber 135 may extend outward from the FAU 150 in the x-direction or in another direction (e.g., the y-direction), as shown in Figure 1. The optical fiber 135 may have a 90° bend, as shown, and near the reflected beam 122, the optical fiber 135 extends in the z-direction, and behind the vent 130, the optical fiber 135 extends in the x-direction.

[0058] Figure 2 shows a top view of several optical interfaces that may be included in the vertical optical coupler 100. Figure 2 shows six optical paths, each including a waveguide 220, a reflector 225 (corresponding to reflector 125), and an optical fiber 235 (corresponding to optical fiber 135) formed within the optical material 104. For example, a first optical path including a waveguide 220a, a reflector 225a, and an optical fiber 235a may be a top view of the optical path shown in Figure 1. In particular, the first optical path includes a waveguide 220a that may correspond to a portion of the optical material 104 transmitting the beam 120, a reflector 125a that may correspond to the reflector 225 in Figure 1, and an optical fiber 135a that corresponds to the optical fiber 235 in Figure 1. For illustrative purposes, the housing material 108 and coupling material 110 are not shown. As another example, the second optical path includes a waveguide 220b, a reflecting surface 225b, and an optical fiber 235b, which are similar to 220a, 225a, and 235a. The optical paths extend parallel to each other at a pitch of 210. The pitch 210 may be, for example, between 50 and 250 μm, or any range therein. In some embodiments, the reflecting surfaces may be arranged in a staggered pattern, for example, as shown in the example in Figure 4B.

[0059] The architectures shown in Figures 1 and 2 are not suitable for a detachable interface due to the high alignment accuracy required between the FAU150 and PIC140. The alignment requirements arise from the inherent short-wavelength nature of optical communication (e.g., between 1.31 and 1.55 μm), resulting in mode field diameters (MFDs) of approximately 10 μm for both single-mode fibers (SMFs) and SSCs. Since coupling efficiency is determined by the integrated overlap of optical modes in the fiber and SSC, a mismatch of 1 or 2 μm between the FAU150 and PIC140 can result in significant coupling loss. Therefore, the PIC140 and FAU150 are aligned and permanently bonded using coupling material 110. Because the alignment control challenges arise from small MFDs, tolerance requirements can be eased by increasing the MFD. Increasing the beam dimensions can significantly improve alignment tolerances, enabling a detachable interface.

[0060] Figure 3 shows a detachable vertical optical coupler 300 in which the FAU can be detachably coupled to the PIC. To enable detachability, the vertical optical coupler 300 employs a magnifying beam feature that includes two optical lenses, one on the FAU side and one on the PIC side, to collimate the diverging beam. The PIC 340 is similar to the PIC 140 and includes a support structure 102 and an optical layer 360 similar to the optical layer 160, but the PIC 340 further includes an additional lens array layer 310 on top of the optical material 104. The lens array layer 310 includes a lens 315 positioned on top of the reflector 325. The optical path from the reflector 325 to the lens 315 is perpendicular to the optical path of the beam incident on the reflector 325; for example, the incident beam on the reflector 325 is in the x-direction, and the path between the reflector 325 and the lens 315 is along the z-direction. In some cases, the lens array layer 310 is an integrated lens formed directly on the optical layer 360. In some embodiments, the lens array layer 310 is formed as a separate die attached to the top of the optical layer 360, for example by bonding, in such embodiments, the base PIC (including the optical layer 360 and support structure 302) and the lens array layer 310 together may be referred to, for example, as a PIC assembly or photonic device assembly or PIC340.

[0061] Lens 315 is a convex lens that collimates the beam reflected from the reflector 325 and traveling through lens 315 toward the FAU 350. The lens array layer 310 may contain silicon or another single-crystal material, e.g., any of the materials described above with respect to the support structure 102 or optical material 104. In other embodiments, the lens array layer 310 may contain silica or a polymer, and lens 315 may be, for example, a silicon lens or another single-crystal lens, a silica lens, or a polymer lens. Lens 315 is manufactured using grayscale lithography and may be bonded to the upper surface of the optical layer 360, for example, using a bonding material 110. The lens array layer 310 may contain an array of multiple lenses, for example, as shown in Figures 4A and 4B.

[0062] The FAU350 includes a lens 317 positioned above the lens 315 of the PIC340. The lens 317 may be formed within the housing material 108, for example, using grayscale lithography or 3D printing. The lens 317 may be a convex lens with a focal point within the housing material 108. The end of the optical fiber 335 may be at or near the focal point of the lens 317 (for example, within 1 μm, 3 μm, 10 μm, or 20 μm). A vent similar to the vent 130 extends through the housing material 108, and the vent extends in the z direction between the top surface of the FAU350 and the bend of the optical fiber 335.

[0063] The reflector 325 and lens 315 result in an output beam with an enlarged beam dimension, and therefore the optical beam dimension between the FAU350 and PIC340 is larger than that of a conventional interface. The enlarged beam can provide mismatch tolerances up to 10 times larger than those of a conventional optical interface, which enables detachability between the PIC340 and FAU350. In particular, at the interface 330 between the top surface of the PIC340 and the bottom surface of the FAU350, the FAU350 can be removed from and reattached to the PIC340. As another example, a different PIC340 may be mounted on the FAU350, or vice versa (for example, if a first PIC or package containing a first PIC in a larger system including the FAU fails, it can be replaced by mounting a second PIC or a second package on the same FAU).

[0064] On the other hand, precise alignment between the lens array layer 310 and the optical layer 360, and between the lens 317 and the optical fiber 335, can be achieved during wafer-level processing of each component. As a result, the enlarged beam dimensions enable detachability between the FAU and PIC, while both the FAU 350 and PIC 340 can be pre-fabricated through wafer-level processes as monolithic components for assembly. In addition, by correcting the curvature of the lens 315 and / or lens 317, the beam dimensions from the fiber 335 can be adaptively matched with the optical modes within the PIC 340.

[0065] Figure 4A shows a top view of several optical interfaces that may be included in the vertical optical coupler 300. Figure 4A shows six optical paths, each including a waveguide 420, a reflecting surface 415, and an optical fiber 435 formed within the optical material 104. For example, a first optical path including a waveguide 420a, a reflecting surface 425a, a lens stack 415, and an optical fiber 435a may be a top view of the optical path shown in Figure 3. In particular, the first optical path includes a waveguide 420a which may correspond to a portion of the optical material 104 that transmits the beam, a reflecting surface 425a which may correspond to the reflecting section 325 in Figure 3, a lens stack 415a which includes lenses 315 and 317, and an optical fiber 435a which corresponds to the optical fiber 335 in Figure 3. Since lenses 315 and 317 are stacked on top of each other, the lens stack 415a is represented by a single circular contour. For illustrative purposes, the materials of the housing material 108, the bonding material 110, and the lens array layer 310 (except for the contour of the lens stack 415a) are not shown. As another example, the second optical path includes a waveguide 420b, a reflecting surface 425b, a lens stack 415a, and an optical fiber 435b, which are similar to 420a, 425a, 415a, and 435a. The optical paths extend parallel to each other at a pitch of 410. The pitch 410 may be, for example, between 50 and 250 μm.

[0066] In some embodiments, the reflective surfaces and lens stacks may be arranged in a staggered pattern, for example, as shown in the example in Figure 4B. Figure 4B shows an alternative top view of an optical interface that may be included in the vertical optical coupler 300. In Figure 4A, the lens stack 415 and reflective surfaces 425 are arranged along a single line. In Figure 4B, the lens stack 415 is arranged along two lines 450 and 460, or two arrays, that are parallel to each other and offset from each other at different positions along the x-direction, for example. Similarly, the reflective surfaces 425, which are located below the lens stack 415 (as shown in Figure 3), are also arranged along two lines or two arrays 450 and 460. By staggering the lenses and reflective surfaces in this way, the pitch 411 between adjacent optical paths can be made denser compared to the arrangement in Figure 4A. The pitch 411 may be, for example, between 25 and 125 μm.

[0067] Figures 5A, 5B, and 6B show embodiments of the second detachable vertical optical coupler 500. Figure 5A shows a first cross-sectional view of the second detachable vertical optical coupler, and Figure 5B shows a second cross-sectional view of the second detachable vertical optical coupler through plane AA' of Figure 5A. The second optical coupler design includes a PIC540 similar to the PIC340. The PIC540 includes an optical layer 560 similar to the optical layer 360, and the optical layer 560 includes a reflector 525 similar to the reflector 325. The reflector 525 deflects the beam traveling through the optical layer 560. The PIC540 further includes a lens array layer 510 bonded on the optical layer 560, similar to the lens array layer 310 on the optical layer 360. The lens array layer 510 includes a lens 515 similar to the lens 315.

[0068] The second optical coupler design includes a FAU550, which has a different design from the FAU350. In some embodiments, the FAU350 and 550 may each be coupled to the same PIC, for example, either the FAU350 or the FAU550 may be coupled to the PIC340. In the example of Figure 5, the FAU550 is a monolithic fiber housing having a V-groove structure for aligning the optical fiber 535. The FAU550 further includes a curved mirror 517 integrated on the upper side of the FAU550 near the fiber tip. The curved mirror 517 may be a TIR or HRC reflector, as described above. The optical path from the reflector 525 to the curved mirror 517 is perpendicular to the optical path of the beam incident on the reflector 525, for example, the incident beam on the reflector 525 is in the x-direction, and the path between the reflector 525 and the curved mirror 517 is along the z-direction.

[0069] For the optical signal from FAU550 to PIC540, the optical beam from optical fiber 535 is expanded and collimated by the curved mirror 517 with the help of TIR or HRC in the curved mirror 517, achieving an expanded beam on the FAU side. Alternatively, the expanded beam transmitted from PIC540 through FAU550 is focused by the curved mirror 517 at the input to optical fiber 535. The monolithic fiber housing for FAU550 can be processed using various materials and processes, such as laser-assisted etching on bulk glass. FAU550 offers high flexibility and allows for the fabrication of alignment features (e.g., V-groove structure) and optical features (e.g., curved mirror 517) on the same block with very high precision control (e.g., <1 μm).

[0070] The embodiment shown in Figure 5 allows for detachability between the FAU550 and PIC540 due to the enlarged beam dimensions. Furthermore, both the FAU550 and PIC540 can be pre-fabricated through a wafer-level process as monolithic components for assembly. In addition, the lens 515 and curved mirror 517 in this design can be adjusted to match the MFD difference between the optical fiber 535 and the SSC (e.g., the reflector 525), which can reduce the nominal coupling loss compared to conventional coupling solutions.

[0071] In this embodiment, the FAU550 includes a layer of housing material 108, which is a medium for transmitting optical signals, so that an optical beam can travel through the housing material 108. For example, the housing material 108 may be glass. An array of curved mirrors, for example, curved mirrors 517, is formed on a first portion 520 of the layer of housing material 108. The curved mirrors are configured to deflect a beam traveling through the layer of 108, for example, a beam transmitted from a reflector 525 toward an optical fiber 535, as shown in Figure 5A. The first portion 520 has a maximum height 521 between the base of the FAU550 and the top of the mirror 517 at the interface 530 with the PIC 540. The height of the first portion 520 varies depending on the curvature of the mirror 517. The FAU550 further includes an array of optical fibers, for example, optical fibers 535, on a second portion 522 of the layer of housing material 108. The second portion 522 of the layer of housing material 108 has a height 523 that is lower than the maximum height 521 of the first portion 520 of the layer of housing material 108 on which the mirror 517 is formed. The optical fiber 535 has an input configured to receive a deflected beam from the curved mirror 517. Each similar optical fiber along the array has an input configured to receive a deflected beam from a corresponding one of the array of curved mirrors, as shown, for example, in Figure 6.

[0072] Figure 5B shows an array of optical fibers, such as optical fibers 535a and 535b, arranged in V-grooves 555a and 555b formed in the housing material 108. As described above, the V-grooves 555 are grooved structures formed in the housing material 108 and can be precisely manufactured in the housing material 108 to provide a high degree of alignment between the ends of the optical fibers 535 and the curved mirrors 517. The housing material 108 having an array of curved mirrors 517 and a corresponding array of V-grooves 555 can be formed as a single optical structure coupled to the array of optical fibers 535.

[0073] The FAU550 is configured to be attached to and detached from the PIC540 along the interface 530. As described above, the optical signal transmitted across the interface 530 (e.g., from the PIC540 to the FAU550) is a widened beam, and for example, the optical signal may have beam dimensions of at least 5 μm, at least 10 μm, at least 20 μm, at least 50 μm, between 20 and 200 μm, or between 50 and 100 μm. At the interface 530, in particular, within the portion of the interface 530 through which the optical beam passes, the PIC540 and FAU550 may be planar. Other portions of the interface 530 may include alignment features and / or connection features for coupling the PIC540 to the FAU550.

[0074] The arrangement of the curved mirror array 517 corresponds to the arrangement of the lens array in the PIC 540. Figure 6A shows a top view of several optical interfaces that may be included in the vertical optical coupler 500. Figure 6A shows six optical paths, each including a waveguide 620, reflector 525, lens 515, curved mirror 517, and optical fiber 535 formed within the optical material 104. For example, the first optical path, including waveguide 620a, reflector 525a, lens 515a, curved mirror 517a, and optical fiber 535a, may be a top view of the optical path shown in Figure 5A. The reflector 525 is indicated by a pattern corresponding to the reflective surface 617, e.g., HRC or TIR surface. For illustrative purposes, the materials of the housing material 108, coupling material 110, and lens array layer 510 (except for the contours of the lenses 515) are not shown. As another example, the second optical path includes a waveguide 620b, a reflector 525b, a lens 515b, a curved mirror 517b, and an optical fiber 535b. The optical paths extend parallel to each other at a pitch of 610. The pitch 610 may be, for example, between 50 and 250 μm.

[0075] In some embodiments, the stacks of reflectors, lenses, and curved mirrors are staggered, as shown in the example in Figure 6B. Figure 6B shows an alternative top view of an optical interface that may be included in the vertical optical coupler 500. In Figure 6A, the reflectors, lenses, and curved mirrors are arranged along a single line. In Figure 6B, the stacks of reflectors, lenses, and curved mirrors are parallel to each other and arranged along two lines 650 and 660, or two arrays, that are offset from each other at different positions along the x-direction. Each of the arrays 650 and 660 extends along the y-direction, perpendicular to the incident path of the light beam toward the reflector 525 (i.e., the x-direction) and perpendicular to the reflected path of the light beam through the interface 530 (i.e., the z-direction). By staggering (alternating) the reflectors, lenses, and curved mirrors in this way, a closer pitch 611 between adjacent optical paths can be allowed compared to the arrangement in Figure 6A. The pitch 611 may be, for example, between 25 and 125 μm.

[0076] In the example in Figure 6B, the V-grooves 555 corresponding to different curved mirrors have different lengths, with the first portion of the V-grooves 555 corresponding to the curved mirrors along array 650 being shorter than the second portion of the V-grooves 555 corresponding to the curved mirrors along array 660. In other words, in the x-direction, the V-grooves corresponding to the curved mirrors along array 660 extend closer to the curved mirrors along array 660 than the V-grooves corresponding to the curved mirrors along array 650. The short and long V-grooves alternate, for example, with each short V-groove located between an adjacent pair of long V-grooves.

[0077] Figure 7 shows cross-sectional views of the third detachable vertical optical coupler 700 in various embodiments. The vertical optical coupler 700 includes a self-locking-based coupling solution through the design of specific geometric relationships between optical components. The self-aligning design essentially maintains symmetry in the optical path and improves offset tolerances, enabling tolerances that are, for example, two to three times greater than those of a widened beam-based solution.

[0078] The third detachable vertical optical coupler 700 includes PIC740 and FAU750. PIC740 includes a support structure 102 and an optical layer 760 similar to the optical layers 160, 360, and 560. Optical layer 760 includes an array of reflectors similar to reflectors 325 and 525, e.g., reflector 725. PIC740 further includes a lens array layer 710 bonded on top of optical layer 760. The lens array layer 710 includes a reflective lens 715 offset from the reflector 725. The optical path from the reflector 725 passes over the upper surface of 710 without passing through the reflective lens 715. Furthermore, unlike lenses 315 and 515, which were convex lenses, the reflective lens 715 is a concave lens, e.g., the reflective lens 715 is a concave mirror.

[0079] On the FAU750, an array of symmetrical curved mirror structures, such as reflective lenses 717, is fabricated on a monolithic housing. The reflective lenses 717 are located in a cavity 720 formed within the bulk material (here, housing material 108) used to form the FAU750. The cavity 720 and the reflective lenses 717 may also be along the front surface of the FAU750, which can be detachably coupled to the PIC740.

[0080] The cavity 720 has a height 721 corresponding to the distance 721 between the reflective lenses 715 and 717. The height 721 of the cavity may be, for example, between 10 and 50 μm. Like the reflective lens 715, the reflective lens 717 is a concave mirror, and therefore the shape of the reflective lens 717 extends into the housing material 108. For example, the shape of the reflective lens 717 may be formed subtractively from the glass housing material 108 by removing a first portion of glass to form the cavity 720 and removing an additional portion of glass to shape the reflective lens 717. Alternatively, the housing material 108 may be a polymer, and the shapes of the cavity 720 and the reflective lens 717 may be printed on the polymer. The reflective lens 717 is positioned to deflect light, in particular toward the reflective lens 715, so that it moves away from the FAU 750 and back toward the PIC 740.

[0081] The design of the third detachable vertical optical coupler 700, having a pair of reflective lenses 715 and 717, aims to direct the optical path from PIC 740 to reflect multiple times before coupling to fiber 735 on FAU 750. The ends of the optical fibers 735 (e.g., the input to optical fiber 735) are located in different parts of cavity 720 and offset from reflective lens 717 in the x-direction. FAU 750 includes a monolithic fiber housing, which may be manufactured using a 2D ferrule array to guide the optical fibers 735 and bend them perpendicularly in their direction, as described with respect to Figure 1.

[0082] The multiple reflection design helps improve alignment tolerances and coupling efficiency by effectively managing the optical path within the connector structure. When an in-plane offset (e.g., an offset in the x-direction) occurs between the pair of reflective lenses 715 and 717, the resulting offset on the first reflective lens 715 produces an exact but opposite offset on the second reflective lens 717; that is, the symmetrical double concave mirrors compensate for each other in terms of planar offset. This self-locking coupler improves tolerances for lateral offsets by at least twice compared to other magnified beam-based couplers.

[0083] Furthermore, the tilt orientation between PIC740 and FAU750 (e.g., rotation in the xz plane) can also be precisely controlled by coplanar contact between the lens array layer 710 and the bottom surface of FAU750 with very tight surface flatness tolerances. Thus, based on the self-locking mechanism between PIC740 and FAU750, the lateral offset tolerance can be substantially improved without further increasing the beam size, and therefore it can function as a detachable user interface. Moreover, when HRC is applied to the reflective surfaces (i.e., the reflector 725, the reflecting lens 715, and the reflecting lens 717), the total internal reflection loss in this optical path can be less than 0.1 dB. This is because the HRC efficiency is typically achievable at 99% or higher. Overall, the third detachable vertical optical coupler 700 tolerates alignment errors between the transmitting assembly (e.g., PIC740) and the receiving assembly (e.g., FAU750) of at least 100 μm with a coupling loss of less than -1 dB.

[0084] In some embodiments, the reflective lenses 715 and 717 are spherical. In other embodiments, the reflective lenses 715 and 717 are toric. Using toric lenses allows for increased offset tolerances in the detachable assembly process. To maintain a small angle of incidence on the reflective lens 717, the horizontal distance between the reflective lens 717 and the reflector 725 should be minimized. This is because, in the case of a curved mirror, a large angle of incidence can lead to beam shape distortion and high coupling loss due to beam mismatch. Therefore, reducing the diameter of the reflective lens 717 prevents the reflective lens 717 and the reflector 725 from obstructing the optical path. However, this limitation on lens diameter limits the offset tolerance due to the aperture effect of the curved mirror. To overcome this challenge, toric lenses, a type of non-axisymmetric lens having different radii of curvature (ROC) along two orthogonal axes, can be used. The reflective lens 715 may have a corresponding toric shape. A toric lens may have a larger ROC in the x-direction (e.g., the direction between the reflective lens 717 and the end of the optical fiber 735) than in the y-direction. The toric lens shape is designed to compensate for beam distortion at larger angles of incidence, thereby eliminating the limitations on lens diameter imposed by spherical lenses.

[0085] Figure 8A shows a first exemplary top view of the third vertical optical coupler 700 of Figure 7 according to various embodiments. Figure 8A shows six optical paths, each including a waveguide 820, reflector 725, reflective lens 717, reflective lens 715, and optical fiber 735 formed within the optical material 104. For example, a first optical path including waveguide 720a, reflector 725a, reflective lens 717a, reflective lens 715a, and optical fiber 735a may be a top view of the optical path shown in Figure 7. For illustrative purposes, the materials of the housing material 108, coupling material 110, and lens array layer 710 (except for the contour of lens 717) are not shown. As another example, a second optical path includes waveguide 720b, reflector 725b, reflective lens 717b, reflective lens 715b, and optical fiber 735b. The optical paths extend parallel to each other at a pitch of 810. The pitch 810 may be, for example, between 50 and 250 μm.

[0086] In some embodiments, the stacks of reflectors and reflective lenses are staggered, as shown in the example in Figure 8B. Figure 8B shows an alternative top view of an optical interface that may be included in the vertical optical coupler 700. In Figure 8A, the reflectors and lenses are generally arranged along a single line, for example, each of the lenses 717 is arranged along a single line, and each of the lenses 715 is arranged along another line slightly offset from lens 717. In Figure 8B, the stacks of reflectors and reflective lenses are generally parallel to each other and are arranged along two lines 850 and 860, or two arrays, offset from each other at different positions along the x-direction. Each of the arrays 850 and 860 extends along the y-direction, which is perpendicular to the incident path of the light beam toward the reflector 725 (i.e., the x-direction). By arranging the reflectors, lenses, and curved mirrors in a staggered pattern (alternating), it is possible to achieve a closer pitch 811 between adjacent optical paths (for example, between 25 μm and 125 μm) compared to the arrangement in Figure 8A.

[0087] Each of the embodiments shown in Figures 1 to 8 includes reflective portions 125, 325, 525, or 725 formed in the optical layers 160, 360, 560, or 760. Angled reflective surfaces or inclined mirrors can be formed within the optical layers using different reflective portion designs and corresponding processing techniques.

[0088] Figures 9A, 9B, 9C, and 9D show cross-sectional views of four exemplary implementations of an angled reflector for use in any of the embodiments of Figures 1 to 8. Each example in Figures 9A to 9D includes an optical channel 902, e.g., a waveguide, formed within the optical material 104. The optical channel 902 is oriented along the x-direction toward an inclined mirror 106 having a reflector. In Figure 9A, the embedded mirror 910 in the optical layer may have a parallelogram cross-section with a reflector 911 and a second surface 912 parallel to the reflector 911. The embedded mirror 910 may be formed on a wafer by tilting the wafer and etching an opening for the embedded mirror 910, for example, using dry etching. The interior of 910 (between the reflector 911 and the second surface 912) may be air, and a cap (e.g., silicon dioxide) may be deposited on the etched opening to seal the air gap between the reflector 911 and the second surface 912. For example, the silicon oxide cap may be present on the upper part 913 of the embedded mirror 910 or on the base 914 of the embedded mirror 910, depending on the direction from which the embedded mirror 910 was etched.

[0089] In other embodiments, a reflective material such as aluminum may be deposited within the opening. The reflective material can completely fill the opening or line the walls of the opening (e.g., the reflective surface 911 and the second surface 912). The reflective material can be deposited using a conformal deposition process. For example, atomic layer deposition (ALD) or chemical vapor deposition (CVD) can be used. Conformal deposition generally refers to the deposition of a particular coating on any exposed surface of a given structure. Thus, a conformal coating can be understood as a coating applied to exposed surfaces of a given structure, not just horizontal surfaces, for example.

[0090] In some cases, if the distance between the reflective surface 911 and the second surface 912 is relatively small, it may be difficult to deposit the reflective material within the opening. In some cases, an enlarged opening may be formed and filled, for example, as shown in Figure 9B. In Figure 9B, the embedded mirror 920 has a trapezoidal shape with a reflective surface 921 similar to the reflective surface 911 and a second surface 922 that is not parallel to the reflective surface 921 but is instead oriented perpendicularly. The reflective surface 921 may be formed by etching a tilted wafer, as described with respect to Figure 9A. An additional etching process may be performed on a non-tilted wafer (i.e., a standard horizontal orientation for wafer processing) to widen the opening, resulting in the second surface 912. The tilted etching and horizontal etching processes may be performed in either order. After etching the opening, the opening is filled with the reflective material to obtain an embedded mirror 920 having the reflective surface 921, the second surface 922, the top 923, and the bottom 924. The second surface 922 is perpendicular to the top 923 and the bottom 924. The first angle between the upper part 923 and the reflective surface 921 may be substantially the same as the second angle between the upper part 923 and the second surface 922. For example, the first angle may be within 5%, 10%, 15%, or 20% of the second angle, or the first angle may be within 5°, 10°, 15°, or 20° of the second angle.

[0091] Figure 9C shows another embodiment of a trapezoidal embedded mirror 930 having a reflective surface 931 and a second surface 932 extending from a top 933 at the same angle as the reflective surface 931. The trapezoidal shape of the embedded mirror 930 may be formed in a single etching process, which is controlled to produce inclined surfaces 931 and 932. Similar to the embedded mirror 910, the embedded mirror 930 may be filled with reflective material or capped with air.

[0092] In each of Figures 9A to 9C, the optical layer includes a first layer having an optical channel 902 and a recessed mirror 910, 920, or 930, and a second layer of optical material 104 below the first layer. In such cases, the recessed mirror and the optical channel 902 may be formed from the bottom surface (in the orientation shown) of the first layer, and the second layer of optical material 104 may then be bonded to the bottom surface of the first layer. The optical channel 902 may also be a waveguide, and the bottom layer may function as cladding for the underside of the waveguide.

[0093] In other embodiments, such as the example in Figure 9D, the embedded mirror may be formed after the second layer is bonded beneath the first layer containing the optical channel 902. In Figure 9D, the embedded mirror 940 has a similar shape to the embedded mirror 930 but is located in a different position. In this example, the upper part 943 of the embedded mirror 940 is below the upper surface of the upper optical layer. In the examples of Figures 9A to 9C, the upper part of the embedded mirror may be below the upper surface of the upper optical layer. Furthermore, in Figure 9D, the upper part 943 may be coplanar with the upper part of the upper optical layer, for example, as shown in Figure 9C.

[0094] In the example shown in Figure 9D, the bottom 944 of the embedded mirror 940 aligns with the bottom of the lower optical layer. If any of the embedded mirrors 910, 920, and 930 extend through the lower optical layer and are formed after the lower optical layer is bonded to the upper optical layer, they may have a bottom aligned with the lower optical layer.

[0095] In Figure 9D, the reflective material forming the mirror 106 is deposited along the reflective surface 941, the second surface 942, and the top 943 of the embedded mirror 940, forming the first layer of the embedded mirror 940. Then, the filler material 904 is deposited in the remaining opening, forming the second layer or filler layer of the embedded mirror 940. In this example, the filler material 904 extends along the bottom 944 of the embedded mirror 940. In other embodiments, another layer of reflective material is deposited on top of the filler material 904, so that in cross-section, the reflective material forms all four sides of the trapezoidal shape of the embedded mirror 940.

[0096] Figures 10–15 illustrate additional embodiments of optical interfaces that rely on evanescent coupling for transmitting optical signals. Evanescent coupling refers to the transmission of light between two adjacent waveguides or optical fibers without physical contact. This transmission occurs via evanescent waves, which are exponentially attenuating electromagnetic fields extending beyond the waveguide core. When two waveguides are close enough, their evanescent fields interact, allowing energy to be transferred from one waveguide to the other. The strength of this coupling depends on the distance between the waveguides and the overlap of their modes. When the waveguides are very close, the coupling can be very strong, but as the waveguides are farther apart, the coupling weakens rapidly due to the exponential attenuation of the evanescent waves.

[0097] Figures 10-12 illustrate an embodiment of a bridge-based optical coupler based on evanescent coupling. The bridge is a pitch-converting interposer that bridges an optical fiber and a PIC waveguide. Figure 10 is a side view including the bridge 1015 and a soft coupler 1020. The soft coupler 1020 is coupled to the optical fiber 1035 by a potentially detachable fiber connection 1030. Multiple PICs 1010 are arranged on the bridge 1015. The PICs 1010 may include optical waveguides, for example, as described with respect to Figure 1. Waveguides in PICs 1010a and 1010b (e.g., waveguides 1012a and 1012b, respectively) are coupled to a waveguide in the bridge 1015 (e.g., waveguide 1017) by evanescent coupling, as indicated by wavefronts extending inside and outside waveguides 1012 and 1017. An additional IC, such as a PIC1010c, can be stacked on top of the bridge 1015 and / or one or more of the PIC1010a and 1010b. In this example, the PIC1010c is stacked on top of the PIC1010b.

[0098] The waveguide in bridge 1015 is coupled to the waveguide in soft coupler 1020 by evanescent coupling. Figure 11A shows the interface between bridge 1015 and soft coupler 1020 in more detail, and Figure 11B is a cross-sectional view through planar BB' of Figure 11A. Figure 12 shows a top view of the coupler shown in Figure 10.

[0099] The soft coupler 1020 may include multiple soft waveguides on a flexible substrate. The flexible substrate may include, for example, a polymer, plastic, soft glass, organic crystal, hydrogel, or other flexible optical material. Strip waveguides may be made from the same type of flexible material but have a higher refractive index and can be patterned on the flexible substrate using lithography to function as waveguide cores. The waveguide cores are covered with a flexible material as a cladding layer (e.g., the same type of flexible optical material as the flexible substrate) to form a flexible soft waveguide coupler. By designing the bent waveguide pattern within the soft coupler, pitch scaling can be achieved to reduce the channel distance between adjacent waveguides from approximately 250 μm at the first end 1022 (in a typical fiber connector) to approximately 50 μm at the bridge 1015. Figure 12 provides a top view illustrating the pitch scaling within the soft coupler 1020. The first pitch 1221 between adjacent waveguides 1120a and 1120b entering the fiber connection 1030 is greater than the second pitch 1222 between adjacent waveguides 1120a and 1120b on the bridge 1015 (for example, at least twice as large, at least three times as large, at least four times as large, or at least five times as large). The optical fiber 1035 exiting the fiber connection 1030 may have the pitch 1221 of the waveguide 1120 entering the fiber connection 1030.

[0100] For optical coupling between the PIC1010 and the fiber connection 1030, different approaches are used on each side of the soft coupler 1020 to accommodate the difference in form factor between them. On the fiber side, the detachable fiber connection 1030 can be achieved using pinhole alignment and physical contact, similar to a mechanical transfer (MT) fiber connector. The fiber connection 1030 includes a first end 1022 coupled to the waveguide 1120 and a second end 1032 coupled to the optical fiber 1035. In some embodiments, this fiber connection 1030 can achieve a 3-sigma loss of <0.4 dB. Secondly, on the optical bridge side, to accommodate the smaller form factor after pitch scaling, the waveguide of the soft coupler 1020 is coupled to the waveguide in the bridge 1015 (e.g., waveguide 1017) by evanescent coupling (EVC). EVCs are vertical coupling mechanisms that enable direct optical signal transfer between two parallel optical waveguides positioned close together. Compared to edge couplings, EVCs have a much smaller form factor due to their vertical stack structure achieved through bonding technology, making them very suitable for high-density waveguides.

[0101] A key challenge in conventional EVCs is controlling the bonding layer thickness (BLT) at the interface between the bridge 1015 and the soft coupler 1020. A bonding layer 1130 with a thickness of 1131 is shown in Figures 11A and 11B. Typically, EVCs are possible with a BLT of less than 1 μm or less than 2 μm. This thickness can be difficult to achieve over large bonding regions. Soft waveguides enable lower BLTs over large bonding regions. Unlike conventional EVCs, which are typically implemented with glass couplers, soft couplers can conform to surface topography and are therefore less sensitive to warping and tilt effects. This results in significantly better reduction of bonding losses, higher warping resistance, and thus improved package stability.

[0102] However, with soft waveguide couplers, as well as conventional glass couplers, reducing the pitch dimension to less than approximately 50 μm remains difficult. This is because the dimensions of these waveguides are still significantly larger than those of the PIC waveguides due to the small refractive index contrast. To address this challenge, the soft coupler 1020 is connected to a bridge 1015 that includes a surface waveguide on, for example, a silicon-on-insulator (SOI) or glass substrate. The bridge 1015 facilitates a second stage of pitch scaling before the PIC 1010. The bridge 1015 scales the pitch between adjacent channels from a pitch 1222 where waveguide 1120 is coupled to waveguide 1017 (e.g., waveguides 1017a and 1017b) to a smaller pitch 1223 where waveguide 1017 is evanescently coupled to waveguide 1012 in PIC 1010a and / or 1010b. In some embodiments, the pitch 1223 is less than 10 μm or less than 5 μm. The pitch 1222 may be, for example, at least twice, at least three times, at least four times, at least five times, or at least ten times larger than the pitch 1223. Pitch scaling within the bridge 1015 and soft coupler 1020 can increase the maximum channel density available on the PIC compared to conventional optical couplers.

[0103] Specifically, the optical interfaces shown in Figures 10 to 12 include an optical bridge 1015, which includes a first pair of waveguides 1017a and 1017b located on a first surface (e.g., the top surface) of the optical bridge. The top surface of waveguide 1017 may be directly on the top surface of bridge 1015, or a thin cladding layer, such as the cladding 1119 shown in Figures 11A and 11B, may cover the top surface of waveguide 1017. Waveguides 1017 are arranged with a first pitch 1222 in one part of bridge 1015 and a second pitch 1223 in another part of the optical bridge, where the first pitch 1222 is greater than the second pitch 1223. The first pitch 1222 may be, for example, between 20 and 100 μm. The second pitch 1223 may be, for example, less than 20 μm, less than 10 μm, or less than 5 μm.

[0104] The second pair of waveguides 1120a and 1120b are positioned above the first pair of waveguides 1017a and 1017b, respectively, in the first portion of the optical bridge 1015, in which region the second pair of waveguides 1120a and 1120b are positioned with a first pitch 1222. In the portion of the second pair of waveguides 1120a and 1120b that is not above the optical bridge 1015, the third pitch 1221 is greater than the first pitch 1222. The third pair of waveguides, for example, the second parallel waveguide in waveguide 1012a and PIC 1010a, are positioned above the first pair of waveguides 1017a and 1017b in the second portion of the optical bridge 1015. The third pair of waveguides are positioned with a second pitch 1023. Waveguide 1017 in optical bridge 1015 connects waveguide 1120 in soft coupler 1020 to waveguide 1012 in PIC 1010, for example, waveguide 1012a in PIC 1010a, enabling communication.

[0105] The distance between waveguide 1017 and waveguide 1012 (specifically, between waveguide 1017 and waveguide 1012 directly above waveguide 1017) may be less than 10 μm, less than 5 μm, less than 3 μm, less than 2 μm, or less than 1 μm. The distance between waveguide 1017 and waveguide 1120 (specifically, between waveguide 1017 and waveguide 1120 directly above waveguide 1017) may be less than 10 μm, less than 5 μm, less than 3 μm, less than 2 μm, or less than 1 μm. For example, the thickness of the bonding layer 1130 may be less than 10 μm, less than 5 μm, less than 3 μm, less than 2 μm, or less than 1 μm. Similarly, the thickness of the bonding layer between PIC1010 and bridge 1015 may be less than 10 μm, less than 5 μm, less than 3 μm, less than 2 μm, or less than 1 μm.

[0106] Figures 13-15 show another optical coupling structure that relies on evanescent coupling to transfer optical signals. In Figure 13, a 3D waveguide structure 1320 is bonded to the PIC1310. The 3D waveguide structure 1320 may also be attached to the PIC1310 at the wafer level, enabling high precision. For example, a hybrid junction can enable a junction pitch of sub-10 μm. The PIC1310 includes a waveguide such as the waveguide 1312 shown in Figure 13. Waveguide 1312 may be similar to the waveguide described with respect to Figure 1. Waveguide 1312 runs along the top surface of the PIC1310. In some embodiments, a thin layer of cladding may be on top of the waveguide 1312, for example, as described with respect to Figure 11. The PIC1310, including waveguide 1312, is located within a first layer 1315 of the assembly.

[0107] The 3D waveguide structure 1320 includes waveguides 1322a, 1322b, and 1322c. In the first region 1340 of the 3D waveguide structure 1320, waveguide 1322 extends along the underside of the 3D waveguide structure 1320, directly above the corresponding waveguide in the PIC 1310. In this region 1340, optical signals are communicated between waveguides 1312 and 1322 using evanescent coupling. Waveguide 1322 is located within the 3D waveguide structure 1320 to convert a 2D array of channels (in region 1340) into a 3D array using multiple stacked waveguides, and waveguide 1322 is stacked within the second region 1342 of the 3D waveguide structure 1320.

[0108] The 3D waveguide structure 1320 may be formed from a glass wafer, and the waveguide 1322 may be formed within the glass wafer using laser direct writing. Glass wafers are available in a wide range of thicknesses and sizes that can accommodate a large number of waveguides. Furthermore, glass offers a range of coefficients of thermal expansion (CTE), and glass with a CTE close to that of silicon (if the PIC1310 is silicon-based) can eliminate or reduce thermal stress through thermal cycling experience in the assembly process and operation. Laser-scribed waveguides offer design flexibility such as pitch conversion, height and width fan-out, and waveguide cross-section transitions. In some embodiments, the laser-scribed waveguides are formed at the wafer level, the glass wafer is diced, and then the individualized glass die containing the waveguide 1322 is bonded to the PIC1310.

[0109] The 3D waveguide structure 1320 is coupled to the optical fiber 1335 by a potentially detachable fiber connector 1330. The fiber connector 1330 provides outputs from the PIC 1310 and the 3D waveguide structure 1320. The 3D arrangement of waveguides 1322 in the second region 1342 is mirrored to the arrangement of optical fibers 1335. For example, the fiber connector 1330 couples waveguide 1222a to optical fiber 1335a, waveguide 1222b to optical fiber 1335b, and waveguide 1222c to optical fiber 1335c. In this example, the fiber connector 1330 is located in the same layer 1325 as the 3D waveguide structure 1320. In the example shown in Figure 15, the fiber connector is located above the 3D waveguide structure.

[0110] The 3D waveguide structure 1320 enables scaling up the connection interface between the PIC 1310 and the optical fiber 1335 to a 2D array. The 3D waveguide structure 1320 also provides pitch scaling, which can increase the pitch between adjacent waveguides 1322 moving from the PIC 1310 to the optical fiber 1335. Figure 14A is an exemplary detailed top view of waveguide 1322 illustrating pitch scaling. In the first region 1340, pairs of adjacent waveguides in the y-direction (e.g., waveguides 1322a and 1322b) have a first pitch 1420. In the second region 1342, pairs of adjacent waveguides in the y-direction (e.g., waveguides 1322a and 1322d) have a second pitch 1425, where the second pitch 1425 is greater than the first pitch 1420. For example, the first pitch 1420 may be, for example, less than 50 μm, less than 40 μm, less than 30 μm, or less than 20 μm. The second pitch 1425 may be, for example, greater than 20 μm, or greater than 100 μm.

[0111] Figures 14B and 14C are two cross-sectional views of the waveguide in Figure 14A according to several different embodiments. Figure 14B is a cross-sectional view through plane CC' of Figure 14A, and Figure 14C is a cross-sectional view through plane DD' of Figure 14A. Figures 14B and 14C show that an array of waveguides, for example, a single array of 15 waveguides, is transitioned to a waveguide matrix, for example, a 3x5 matrix.

[0112] In region 1340, each of the waveguides 1322 lies above each of the waveguides 1312 in the PIC. For example, as shown in Figure 14C, waveguide 1322a lies above waveguide 1312a in the PIC 1310, and waveguide 1322b lies above waveguide 1312b in the PIC. In this region 1340, to enable evanescent coupling, the distance between waveguides 1312 and waveguide 1322 (for example, between waveguide 1312a and waveguide 1322a directly above waveguide 1312a) can be less than 5 μm, less than 3 μm, less than 2 μm, or less than 1 μm. In region 1345, part of waveguide 1322 lies above other parts of waveguide 1322. For example, in Figure 14B, waveguide 1322a lies above waveguide 1322b. Waveguide 1322a is further from the first layer 1315 than waveguide 1322b.

[0113] Figure 15 shows an embodiment in which the fiber optic connection 1530 rests on a 3D waveguide structure 1520. In this example, the 3D waveguide structure 1520 includes a reflector 1525 which may be similar to the reflector 325 or other reflectors described with respect to Figures 1 to 9. The reflector 1525 reflects the optical signal traveling in the x-direction in the z-direction and incidents on the fiber optic connection 1530, which is connected to an array of optical fibers in a similar manner to the fiber optic connection 1330. The fiber optic connection 1530 may be detachable.

[0114] Configurations having one or more optical couplers, as disclosed in this specification, may be included in any suitable component or electronic device. Figures 9 to 11 show various examples of devices and components that may include one or more optical couplers, as disclosed in this specification.

[0115] Figure 16 shows a top view of a wafer 2100 and a die 2102, which may include, or be used in conjunction with, one or more optical couplers according to any embodiment disclosed herein. In some embodiments, the die 2102 may be included in an IC package according to any embodiment disclosed herein. For example, any of the dies 2102 may function as any of the dies 2256 in the IC package 2200 shown in Figure 17. The wafer 2100 may be composed of a semiconductor material and may include one or more dies 2102 having an IC structure formed on the surface of the wafer 2100. Each of the dies 2102 may be an iterative unit of a semiconductor product including any suitable IC (e.g., one or more photonic integrated circuits (PICs) as described herein, e.g., an IC including the PIC 2306 in Figure 18). At least some of the dies 2102 may further include, or be coupled to, one or more optical couplers mounted on or attached to the die 102. After the manufacturing of the semiconductor product is completed (for example, after the manufacturing of any embodiment of an optical coupler as disclosed herein), the wafer 2100 may undergo a dicing process in which each die 2102 is separated from one another to provide individual “chips” of the semiconductor product. In particular, a device including one or more optical couplers as disclosed herein may take the form of a wafer 2100 (e.g., undicated) or a die 2102 (e.g., diced). The die 2102 may include support circuits for routing electrical and / or optical signals to various components, such as various optical couplers, as well as various transistors, capacitors, resistors, or any other IC components.

[0116] Figure 17 is a side cross-sectional view of an exemplary microelectronic package 2200 which may include one or more optical couplers according to any embodiment disclosed in this specification. In some embodiments, the microelectronic package 2200 may be a system-in-package (SiP).

[0117] The package substrate 2252 may be formed from a dielectric material (e.g., ceramic, build-up film, epoxy film having filler particles inside), and may have conductive paths 2262 extending through the dielectric material between surfaces 2272 and 2274, or between different positions on surface 2272, and / or between different positions on surface 2274.

[0118] The package substrate 2252 may include conductive contacts 2263 coupled to a conductive path 2262 running through the package substrate 2252, allowing circuits in the die 2256 and / or interposer 2257 to be electrically coupled to various of the conductive contacts 2264 (or to other devices included in the package substrate 2252, which are not shown).

[0119] The microelectronics package 2200 may include an interposer 2257 coupled to the package substrate 2252 via conductive contacts 2261 of the interposer 2257, a first-level interconnect 2265, and conductive contacts 2263 of the package substrate 2252. The first-level interconnect 2265 shown in Figure 17 is a solder bump, but any suitable first-level interconnect 2265 may be used. In some embodiments, the microelectronics package 2200 may not include an interposer 2257, and instead, the die 2256 may be directly coupled to the conductive contact 2263 at a surface 2272 by the first-level interconnect 2265.

[0120] The microelectronics package 2200 may include one or more dies 2256 coupled to the interposer 2257 via conductive contacts 2254 of the die 2256, a first-level interconnect 2258, and conductive contacts 2260 of the interposer 2257. The conductive contacts 2260 may also be coupled to a conductive path (not shown) via the interposer 2257, allowing circuits within the die 2256 to be electrically coupled to various conductive contacts 2261 (or to other devices (not shown) included in the interposer 2257). The first-level interconnect 2258 shown in Figure 17 is a solder bump, but any suitable first-level interconnect 2258 may be used. As used in this specification, “conductive contact” may refer to a portion of a conductive material (e.g., metal) that functions as an interface between different components, and the conductive contact may be embedded in the surface of a component, coplanar with it, or extend away from it, and may take any preferred form (e.g., a conductive pad or socket).

[0121] In some embodiments, the underfill material 2266 may be positioned around the first level interconnect 2265 between the package substrate 2252 and the interposer 2257, and the mold compound 2268 may be positioned around the die 2256 and the interposer 2257 in contact with the package substrate 2252. In some embodiments, the underfill material 2266 may be the same as the mold compound 2268. Exemplary materials that may be used for the underfill material 2266 and the mold compound 2268 are, as appropriate, epoxy mold materials. The second level interconnect 2270 may be coupled to the conductive contact 2264. The second level interconnect 2270 shown in Figure 17 is a solder ball (e.g., for a ball grid array arrangement), but any suitable second level interconnect 22770 may be used (e.g., pins in a pin grid array arrangement, or lands in a land grid array arrangement). The second level interconnect 2270 may be used to connect the microelectronics package 2200 to another component such as a circuit board (e.g., a motherboard), an interposer, or another IC package, as is known in the art.

[0122] Die 2256 may take any form of an embodiment of die 2102 discussed in this specification (for example, including any embodiment of an IC device that implements an optical coupler as disclosed in this specification). In embodiments in which the microelectronics package 2200 includes a plurality of dies 2256, the microelectronics package 2200 may be referred to as a multi-chip package (MCP). Die 2256 may include circuitry that performs any desired function. In some embodiments, any of the dies 2256 may include one or more optical couplers, as described above.

[0123] The microelectronics package 2200 shown in Figure 17 may be a flip-chip package, but other package architectures may be used. For example, the microelectronics package 2200 may be a ball grid array (BGA) package, such as an embedded wafer-level ball grid array (eWLB) package. In another example, the microelectronics package 2200 may be a wafer-level chip scale package (WLCSP) or a panel fan-out (FO) package. Although the microelectronics package 2200 in Figure 17 shows two dies 2256, the IC package 2200 may contain any desired number of dies 2256. The IC package 2200 may include additional passive components such as surface-mount resistors, capacitors, and inductors, which are located on the first surface 2272 or the second surface 2274 of the package substrate 2252, or on either surface of the interposer 2257. More generally, the IC package 2200 may include any other active or passive components known in the art.

[0124] Figure 18 is a block diagram of an exemplary photonic device 2300, which may include one or more components on which the optical coupler disclosed in this specification may be mounted. For example, any suitable component among the components of the photonic device 2300 may include a die (e.g., die 2102 in Figure 16) having one or more microelectronic packages (e.g., microelectronic package 2200 in Figure 17).

[0125] While several components are shown in Figure 18 as being included in the photonic device 2300, any one or more of these components may be omitted or replicated as appropriate for the application. In some embodiments, some or all of the components included in the photonic device 2300 may be mounted on one or more motherboards or any suitable support structure. In some embodiments, some or all of these components are fabricated on a single system-on-chip (SoC) die. Furthermore, in various embodiments, the photonic device 2300 may not include one or more of the components shown in Figure 18, but the photonic device 2300 may include interface circuits for coupling to one or more components. For example, the photonic device 2300 may not include the processor 2322, but may include processor interface circuits (e.g., connectors and driver circuits) to which the processor 2322 can be coupled. In another example, the photonic device 2300 may not include the memory 2324, but may include memory interface circuits (e.g., connectors and driver circuits) to which the memory 2324 can be coupled. In yet another example, the photonic device 2300 does not have to include the circulator 2318, but may include a circulator interface circuit (e.g., a connector) to which the circulator 2318 can be coupled.

[0126] In some embodiments, the photonic device 2300 may include at least one light source 2302. The light source 2302 may include any suitable device for providing the optical signals required for various applications of the photonic device 2300, ranging from communication to sensing and imaging. The light source 2302 may be designed to emit light in a controlled and efficient manner to meet specific requirements of the photonic device 2300. In some embodiments, the light source 2302 may be a coherent and monochromatic light source, such as a laser, to produce light with a well-defined wavelength, low divergence, and high brightness. Examples of lasers that may be included in the light source 2302 include semiconductor lasers such as end-emitting lasers and vertical-cavity surface-emitting lasers (VCSELs). Such lasers may be particularly advantageous when the photonic device 2300 is used in applications such as optical communication, sensing, and laser-based therapy in medical devices. In some embodiments, the light source 2302 may be a non-coherent light source, such as an LED that emits light when an electric current is applied. LEDs can be simpler and more cost-effective than lasers and are suitable for applications where high coherence is not required. Using LEDs as the light source 2302 can be particularly advantageous when the photonic device 2300 is used in applications such as displays, optical sensors, and short-range communication systems. In further embodiments, the light source 2302 may include one or more of the following: superluminescent diodes (SLDs), quantum dots, rare-earth doped fibers / waveguides, plasma sources (e.g., plasmonics and microplasma devices), microcavity resonators, or nonlinear optical devices (e.g., photonic devices that generate new wavelengths using nonlinear optical processes such as frequency doubling or parametric amplification).

[0127] In some embodiments, the photonic device 2300 may include at least one optical guide component 2304, such as a waveguide, to manipulate and control the propagation of light. The optical guide component 2304 includes any suitable waveguide structure designed to confine and guide light along a specific path, allowing light to travel from one point to another with minimal loss and dispersion. Examples of waveguides that can be used as the optical guide component 2304 include planar waveguides, optical fibers, photonic crystal waveguides, and rib waveguides. In some embodiments, the optical guide component 2304 may include a material having a higher refractive index, known as a "core," surrounded by a material having a lower refractive index, known as a "cladding." The difference in refractive index between the core and the cladding helps guide light within the core by using internal total internal reflection. The light is confined within the core by reflection at the core-cladding interface. The optical guide component 2304 may support the propagation of various modes of light, such as single-mode or multi-mode.

[0128] In some embodiments, the photonic device 2300 may include at least one PIC2306. The PIC2306 may be a miniaturized integrated optical device that incorporates photonic components such as optical modulators, photodetectors, and waveguides on a single substrate. In some embodiments, the PIC2306 may include one or more optical modulators for encoding data onto an optical signal, for example, onto light generated by a light source 2302. The optical modulators of the PIC2306 can modify certain characteristics of the optical signal, such as its amplitude, frequency, or phase, in order to encode information into a signal or to perform various signal processing functions. Examples of optical modulators that may be implemented in the PIC2306 include electro-optic modulators, Mach-Zehnder interferometric (MZI) modulators, or microring modulators. In some embodiments, the PIC2306 may include one or more photodetectors for detecting and measuring the intensity of light or optical radiation across various wavelengths by converting incident light / photons into electrical signals. Examples of photodetectors that can be implemented in the PIC2306 include photodiodes, avalanche photodiodes, phototransistors, PIN diodes, CMOS image sensors, photomultiplier tubes, or quantum photodetectors. In some embodiments, the PIC2306 may include one or more waveguides, for example, any of the waveguides described with reference to the optical guide component 2304.

[0129] In some embodiments, the photonic device 2300 may include at least one optical coupling component 2308. The optical coupling component 2308 may include any suitable structure designed to facilitate the efficient transmission of light between different optical devices, for example, between a light source 2302 and a light guide component 2304, between a light source 2302 and a PIC 2306, between a light guide component 2304 and a PIC 2306, or between a light guide component 2304 or a PIC 2306 and a further transmission line, such as a fiber (not shown in Figure 18), which can be coupled to the photonic device 2300. Examples of optical coupling elements that may be used to implement the optical coupling component 2308 include fiber couplers (e.g., fused fiber couplers or tapered fiber couplers), waveguide couplers, grating couplers, lens couplers, microlens couplers, prism couplers, fiber array couplers, or ball lens couplers. In some embodiments, the optical coupling component 2308 may include one or more optical couplers as described herein.

[0130] In some embodiments, the photonic device 2300 may include at least one wavelength splitter / multiplexer 2310 for coupling or splitting multiple optical signals carried at different wavelengths. This may be particularly advantageous when the photonic device 2300 is used in optical communication systems such as wavelength division multiplexing (WDM) systems or dense wavelength division multiplexing (DWDM) systems, where multiple data channels are transmitted simultaneously over a single optical fiber using light of different wavelengths. In various embodiments, the wavelength splitter / multiplexer 2310 may include wavelength division multiplexers, wavelength division demultiplexers, passive optical add / drop multiplexers, array waveguide gratings, fused fiber couplers, and interleavers, or optical filter-based devices.

[0131] In some embodiments, the photonic device 2300 may include at least one polarization splitter / multiplexer 2312 to combine or split multiple optical signals according to their polarization. Similarly, in some embodiments, the photonic device 2300 may include at least one polarization control component 2314 to control the polarization of the light generated and manipulated within the photonic device 2300. In various embodiments, the polarization splitter / multiplexer 2312 and the polarization control component 2314 may include any suitable structure that enables the manipulation and control of polarization signals, such as birefringent materials, waveguide structures, or special coatings that interact with different polarization states in different ways.

[0132] In some embodiments, the photonic device 2300 may include at least one general-purpose power splitter / multiplexer 2316 to combine or split multiple optical signals in a wavelength or polarization-independent manner. For example, in some embodiments, the power splitter / multiplexer 2316 can be used to extract a small amount of optical power for power monitoring purposes in the photonic device 2300. Examples of devices that can be used as the power splitter / multiplexer 2316 include directional couplers and multimode interference couplers.

[0133] In some embodiments, the photonic device 2300 may include at least one circulator 2318, also called a “directional splitter.” The circulator 2318 may include any suitable device configured to guide an optical signal through its ports to travel within a specific unidirectional circular path. In some embodiments, the circulator 2318 may include a magneto-optical material or other technique that produces a Faraday rotation effect, where the polarization of the light is rotated as it passes through the circulator 2318.

[0134] In some embodiments, the photonic device 2300 may include at least one mode splitter / multiplexer 2320 for coupling or splitting multiple optical signals based on their waveguide modes. Examples of devices that can be used as mode splitters / multiplexers 2320 include directional couplers, multimode interference couplers, tapered waveguide couplers, photonic lanthanum, or photonic crystal splitters.

[0135] In some embodiments, the photonic device 2300 may include a processing unit 2232 (e.g., one or more processing units). As used in this specification, the terms “processing unit” or “processor” may refer to any device or part of a device that processes electronic data from registers and / or memory and converts that electronic data into other electronic data that can be stored in registers and / or memory. The processing unit 2322 may include one or more digital signal processors (DSPs), application-specific integrated circuits (ASICs), central processing units (CPUs), graphics processing units (GPUs), cryptographic processors (dedicated processors that execute cryptographic algorithms in hardware), server processors, or any other suitable processing units. In some embodiments, the processing unit 2322 may include circuits for controlling the operation of other components of the photonic device 2300, such as the operation of a PIC2306.

[0136] In some embodiments, the photonic device 2300 may include a memory 2324, which itself may include one or more memory devices such as volatile memory (e.g., DRAM), non-volatile memory (e.g., read-only memory (ROM)), flash memory, solid-state memory, and / or a hard drive. In some embodiments, the memory 2404 may include a memory that shares a die with the processing unit 2232. This memory may be used as a cache memory and may include embedded DRAM (eDRAM) or spin-transfer torque magnetic random-access memory (STT-MRAM). In some embodiments, the memory 2324 may store instructions or data for the processing unit 2322 to control the operation of other components of the photonic device 2300, such as the operation of a PIC 2306.

[0137] The following paragraphs provide examples of various embodiments disclosed in this specification.

[0138] (Example 1) A photonic integrated circuit (PIC), An optical channel extending in the first direction, A reflective portion located at the end of the optical channel and having a surface that is at an angle to the first direction, The lens above the reflective part, A PIC comprising the reflective portion, wherein the optical path from the reflective portion to the lens is perpendicular to the first direction.

[0139] (Example 2) The PIC according to Example 1, further comprising a substrate extending across a plane, wherein the first direction is parallel to the plane of the substrate.

[0140] (Example 3) The PIC according to Example 1 or 2, wherein the reflective portion includes a high-reflectivity coating along the front surface.

[0141] (Example 4) The PIC according to Example 1 or 2, wherein the reflective portion includes a total internal reflection (TIR) ​​reflective portion along the front surface.

[0142] (Example 5) The PIC described in any of Examples 1 to 4, wherein the lens is a convex lens.

[0143] (Example 6) The PIC according to any one of Examples 1 to 5, wherein the lens is configured to collimate light moving from the reflector through the lens.

[0144] (Example 7) The PIC according to any one of Examples 1 to 6, wherein the optical channel is in the first layer, the lens is in the second layer, and the first layer is bonded to the second layer.

[0145] (Example 8) The PIC according to any one of Examples 1 to 7, wherein in a cross-section passing through the reflecting portion, optical channel, and lens, the reflecting portion has a parallelogram shape.

[0146] (Example 9) The PIC according to any one of Examples 1 to 7, wherein in a cross-section passing through the reflecting portion, optical channel, and lens, the reflecting portion is trapezoidal.

[0147] (Example 10) The PIC according to Example 9, wherein the reflective portion has a second surface on the opposite side of the inclined surface, and the second surface is perpendicular to the first direction.

[0148] (Example 11) The PIC according to Example 9, wherein the reflective portion has a second surface opposite to the inclined surface and an upper surface between the inclined surface and the second surface, and the first angle between the inclined surface and the upper surface is within 10° of the second angle between the second surface and the upper surface.

[0149] (Example 12) The PIC according to any one of Examples 1 to 11, wherein the reflective portion includes a reflective material on at least one side surface of the non-reflective internal material.

[0150] (Example 13) A photonic integrated circuit (PIC) assembly, The first layer, Multiple optical channels extending in the first direction, A plurality of reflective portions are arranged at each end of the optical channel, The first layer includes, A lens array on the first layer, wherein the lens array includes a plurality of lenses disposed on corresponding reflective portions among the plurality of reflective portions, A PIC assembly that includes this.

[0151] (Example 14) The PIC assembly according to Example 13, wherein the optical path from one of the plurality of reflectors to the corresponding one of the plurality of lenses is perpendicular to the first direction.

[0152] (Example 15) The PIC assembly according to Example 13 or 14, wherein the first portion of the plurality of lenses is arranged along a first line, the second portion of the plurality of lenses is arranged along a second line, and the first line is parallel to the second line and offset with respect to the second line.

[0153] (Example 16) The PIC assembly according to any one of Examples 13 to 15, wherein the lens is a convex lens formed in a layer of silicon.

[0154] (Example 17) An assembly, An array of convex lenses positioned at the input to the assembly, wherein the convex lenses are arranged in at least two rows, An array of optical fibers, wherein one input of the optical fiber is located at one focal point of the array of convex lenses, An assembly that includes this.

[0155] (Example 18) The assembly according to Example 17, wherein one of the optical fibers is bent at a 90° angle.

[0156] (Example 17) The assembly of Example 17 or 18, further comprising a ventilation hole on the bent portion of the optical fiber, wherein the ventilation hole extends in the direction of the optical fiber at the input portion of the optical fiber.

[0157] (Example 17) The assembly is detachable from a second component, the second component comprising a plurality of optical outputs having a second plurality of convex lenses arranged in at least two rows, as an assembly of any of Examples 17 to 19.

[0158] (Example 21) An assembly, A layer of medium for transmitting optical signals, An array of curved mirrors on the aforementioned layer, wherein one of the curved mirrors is configured to deflect a beam moving through the aforementioned layer, An array of optical fibers on a portion of the aforementioned layer, wherein each of the optical fibers has an input configured to receive a beam deflected from a corresponding one of the curved mirrors, An assembly that includes this.

[0159] (Example 22) The assembly of Example 21, wherein the assembly is configured to be attached to and removed from a second assembly, and the second assembly is configured to transmit optical signals.

[0160] (Example 23) The assembly of Example 22, wherein the second assembly includes a plurality of lenses having an arrangement corresponding to the array of curved mirrors.

[0161] (Example 24) The assembly of Example 22 or 23, wherein the optical signal transmitted by the second assembly is an expanded beam.

[0162] (Example 25) An assembly of any of Examples 21-24, wherein the array of curved mirrors is configured to receive a beam having a beam dimension of at least 5 μm.

[0163] (Example 26) An assembly of any of Examples 21-25, wherein the beam path of the optical signal passing through the layer is perpendicular to the direction in which one of the optical fibers extends.

[0164] (Example 27) An assembly of any of Examples 21-26, wherein one of the optical fibers is coupled to a layer of a medium for transmitting optical signals using a v-groove structure.

[0165] (Example 28) Any assembly from Examples 21-27, wherein the medium for transmitting optical signals is glass.

[0166] (Example 29) The assembly according to Example 28, wherein the glass is molded to provide the curved shape of the curved mirror.

[0167] (Example 30) The assembly according to Example 29, wherein the curved mirror further includes a high-reflectivity coating applied to the glass.

[0168] (Example 31) A glass layer having a first surface and a second surface opposite to the first surface, An array of curved mirrors along the second surface of the glass layer, wherein one of the curved mirrors is configured to deflect a beam moving in a first direction from the first surface of the glass layer to the second surface of the glass layer, and the deflected beam is directed in a second direction perpendicular to the first direction, An array of groove structures extending along a third direction perpendicular to the first and second directions, wherein each of the groove structures corresponds to one of the curved mirrors, An optical structure containing an optical structure.

[0169] (Example 32) The optical structure of Example 31, wherein a first portion of the array of curved mirrors is arranged along a first line, a second portion of the array of curved mirrors is arranged along a second line, and the first line is parallel to the second line and offset with respect to the second line.

[0170] (Example 33) The optical structure of Example 32, wherein the first portion of the array of groove structures extends in the first direction to a position closer to the first portion of the array of curved mirrors than the second portion of the array of groove structures, the first portion of the groove structures corresponds to the first portion of the array of curved mirrors, and the second portion of the groove structures corresponds to the second portion of the array of curved mirrors.

[0171] (Example 34) The optical structure of Example 33, wherein each of the second parts of the array of groove structures is located between two of the first parts of the array of groove structures.

[0172] (Example 35) An optical structure according to any of Examples 31 to 34, wherein the first surface of the glass layer is planar in the region directly below the curved mirror in the array of curved mirrors.

[0173] (Example 36) The curved mirror is an optical structure according to any of Examples 31 to 35, wherein the curved mirror includes a high-reflectivity coating on the second surface of the glass layer.

[0174] (Example 37) An optical structure according to any of Examples 31 to 36, wherein the array of curved mirrors is configured to receive a beam having a beam dimension of at least 5 μm.

[0175] (Example 38) A transmitting assembly including an optical channel extending in a first direction, A reflective portion located at the end of the optical channel and having a surface that is at an angle to the first direction, A lens on the reflecting portion, wherein the optical path from the reflecting portion to the lens is perpendicular to the first direction, A receiving assembly including a curved mirror configured to deflect the beam from the transmitting assembly, An optical fiber extending parallel to the first direction, having an input configured to receive a deflected beam from a curved mirror, Optical interconnect section including the optical interconnect.

[0176] (Example 39) The transmitting assembly is an optical interconnect unit of Example 38, which is detachable from the receiving assembly.

[0177] (Example 40) An optical interconnect in Example 38 or 39, wherein the reflector in the transmitting assembly is configured to amplify the optical signal from the optical channel relative to the beam dimension of the optical signal in the optical channel.

[0178] (Example 41) A bulk material having a cavity formed on one side of the bulk material, A curved mirror having a concave shape is formed within the cavity, An optical fiber, at least partially surrounded by the bulk material, having an input to the cavity and offset from the curved mirror, An assembly that includes this.

[0179] (Example 42) The assembly according to Example 41, wherein the curved mirror is a toric mirror.

[0180] (Example 43) The assembly of Example 42, wherein a first direction extends between the curved mirror and the optical fiber, a second direction is perpendicular to the first direction, and the toric mirror has a larger radius of curvature in the first direction than in the second direction.

[0181] (Example 44) The assembly according to Examples 41-43, wherein the bulk material is glass and the curved shape of the curved mirror is etched into the glass.

[0182] (Example 45) The assembly according to Examples 41-43, wherein the bulk material is a polymer and the curved shape of the curved mirror is printed on the polymer.

[0183] (Example 46) An assembly of any of Examples 41 to 45, wherein the optical fiber has a bent portion surrounded by the bulk material.

[0184] (Example 47) An assembly of any of Examples 41 to 46, wherein the assembly is configured to be attached to and removed from a second assembly, and the second assembly is configured to transmit an optical signal.

[0185] (Example 48) The assembly according to Example 47, wherein the curved mirror is a first curved mirror, and the second assembly is a second mirror configured to reflect a beam received from the first curved mirror, the reflected beam being directed toward the input to the optical fiber.

[0186] (Example 49) An assembly of any of Examples 41 to 48, wherein the assembly includes a plurality of curved mirrors, including the curved mirror, and the assembly includes a plurality of optical fibers, including the front optical fiber.

[0187] (Example 50) The assembly according to Example 49, wherein the plurality of curved mirrors are arranged along a first row and along a second row, and the first row is parallel to and offset from the second row.

[0188] (Example 51) An insulating material including the front and back surfaces, A curved mirror formed on the front surface of the insulating material, the curved mirror being positioned to deflect the incident beam away from the curved mirror and away from the front surface of the insulating material, An optical fiber at least partially surrounded by the insulating material, having an input on the front surface of the insulating material and offset from the curved mirror, An assembly that includes this.

[0189] (Example 52) The assembly according to Example 51, wherein the front surface of the insulating material has a cavity therein, and the curved mirror is located within the cavity.

[0190] (Example 53) The assembly according to Example 51, wherein the curved mirror is a toric mirror.

[0191] (Example 54) The assembly of Example 53, wherein a first direction extends between the curved mirror and the optical fiber, a second direction is perpendicular to the first direction, and the toric mirror has a larger radius of curvature in the first direction than in the second direction.

[0192] (Example 55) An assembly of any of Examples 51 to 54, wherein the assembly includes a plurality of curved mirrors, including the curved mirror, and the assembly includes a plurality of optical fibers, including the front optical fiber.

[0193] (Example 56) The assembly according to Example 55, wherein the plurality of curved mirrors are arranged along a first row and along a second row, and the first row is parallel to and offset from the second row.

[0194] (Example 57) A transmitting assembly including an optical channel extending in a first direction, A reflective portion located at the end of the optical channel and having a surface that is at an angle to the first direction, The first curved mirror and, A receiving assembly including a second curved mirror configured to deflect the beam from the reflecting part toward the first curved mirror, An optical fiber having an input configured to receive a beam reflected from the first curved mirror, Optical interconnect section including the optical interconnect.

[0195] (Example 58) An optical interconnection unit of Example 57, wherein the first curved mirror and the second curved mirror are toric mirrors.

[0196] (Example 59) The optical interconnect in Example 57 or 58, configured to allow a coupling loss of less than -1 dB and an alignment error of at least 100 μm between the transmitting assembly and the receiving assembly.

[0197] (Example 60) The transmitting assembly is an optical interconnect unit from any of Examples 57 to 59, which is detachable from the receiving assembly.

[0198] (Example 61) An optical bridge having a first pair of waveguides on a first surface of the optical bridge, wherein the first pair of waveguides are arranged at a first pitch in a first portion of the optical bridge and at a second pitch in a second portion of the optical bridge, and the first pitch is greater than the second pitch, A second pair of waveguides arranged on the first pair of waveguides in the first portion of the optical bridge, the second pair of waveguides having the first pitch, A third pair of waveguides arranged on the first pair of waveguides in the second portion of the optical bridge, the third pair of waveguides having the second pitch, An assembly that includes this.

[0199] (Example 62) The assembly according to Example 61, wherein the second pair of waveguides are soft optical waveguides.

[0200] (Example 63) The assembly according to Example 61 or 62, wherein the second pair of waveguides has the first pitch in the first portion of the optical bridge, and the second pair of waveguides has a third pitch in the portion not over the optical bridge, the third pitch being greater than the first pitch.

[0201] (Example 64) The assembly according to any of Examples 61 to 63, wherein the second pair of waveguides are coupled to a detachable interface, and the detachable interface is configured to be coupled to an optical fiber.

[0202] (Example 65) The third pair of waveguides is an assembly of any of Examples 61-64 located within a photonic integrated circuit (PIC).

[0203] (Example 66) Any assembly of Examples 61 to 65, wherein one of the second pair of waveguides is coupled to one of the third pair of waveguides by one of the first pair of waveguides in the optical bridge.

[0204] (Example 67) An assembly of any of Examples 61 to 66, wherein the distance from one of the first pair of waveguides to one of the second pair of waveguides is 5 μm or less.

[0205] (Example 68) An assembly of any of Examples 61 to 67, wherein the distance from one of the first pair of waveguides to one of the third pair of waveguides is 5 μm or less.

[0206] (Example 69) An assembly of any of Examples 61-68, wherein the first pitch is at least five times larger than the second pitch.

[0207] (Example 70) An assembly of any of Examples 61 to 68, wherein the first component including the second pair of waveguides is joined to the first portion of the optical bridge, and the second component including the third pair of waveguides is joined to the second portion of the optical bridge.

[0208] (Example 71) An optical bridge comprising a plurality of surface waveguides formed on a first surface of the optical bridge, wherein the plurality of surface waveguides are arranged at a first pitch in a first portion of the optical bridge and at a second pitch in a second portion of the optical bridge, the first pitch being greater than the second pitch, A plurality of soft waveguides located on the first portion of the optical bridge, wherein one of the plurality of soft waveguides is coupled by evanescent coupling to a corresponding one of the surface waveguides, An assembly that includes this.

[0209] (Example 72) The assembly according to Example 71, wherein the plurality of soft waveguides have the first pitch in the first portion of the optical bridge, and the plurality of soft waveguides have a third pitch in the portion not on the optical bridge, the third pitch being greater than the first pitch.

[0210] (Example 73) The assembly according to Example 71 or 72, wherein the second pitch is less than 10 μm.

[0211] (Example 74) An assembly of any of Examples 71 to 73, wherein the first pitch is between 20 μm and 100 μm.

[0212] (Example 75) An assembly of any of Examples 71 to 74, wherein the distance from one of the plurality of soft waveguides to one of the plurality of surface waveguides is 3 μm or less.

[0213] (Example 76) An assembly of any of Examples 71 to 75, wherein the plurality of soft waveguides are joined to the first portion of the optical bridge.

[0214] (Example 77) An optical bridge including a first plurality of waveguides, A second plurality of waveguides on the first portion of the optical bridge, wherein the first waveguide among the first plurality of waveguides is arranged in relation to the second waveguide among the second plurality of waveguides for evanescent transmission of optical signals, A photonic component on the second portion of the optical bridge, comprising a photonic component including a third plurality of waveguides, An assembly that includes this.

[0215] (Example 78) The assembly according to Example 77, wherein the photonic component is a die and the third plurality of waveguides are silicon waveguides.

[0216] (Example 79) The assembly according to Example 77 or 78, wherein the first plurality of waveguides in the optical bridge are tapered from a first pitch in the first part of the optical bridge to a second pitch in the second part of the optical bridge, and the first pitch is greater than the second pitch.

[0217] (Example 80) The assembly according to Example 79, wherein the third plurality of waveguides are tapered from the third pitch to the first pitch, and the third pitch is greater than the first pitch.

[0218] (Example 81) The first layer and, A plurality of first waveguides extending along the surface of the first layer, The second layer on the surface of the first layer, A second plurality of waveguides in the second layer, wherein in a first region of the second layer, each of the second plurality of waveguides lies on one of each of the first plurality of waveguides, and in a second region of the second layer, one of the second plurality of waveguides lies on another of the second plurality of waveguides, An assembly that includes this.

[0219] (Example 82) The assembly according to Example 81, wherein the first plurality of waveguides include silicon.

[0220] (Example 83) The assembly according to Example 81 or 82, wherein the second layer includes glass.

[0221] (Example 84) The assembly according to Example 83, wherein the second plurality of waveguides are formed using laser writing.

[0222] (Example 85) An assembly of any of Examples 81 to 84, wherein in a first region of the second layer, a first pair of adjacent waveguides has a first pitch, and in a second region of the second layer, a second pair of adjacent waveguides has a second pitch, the second pitch being greater than the first pitch.

[0223] (Example 86) The assembly according to Example 85, wherein the first pitch is less than 40 μm.

[0224] (Example 87) The assembly according to Example 85 or 86, wherein the second pitch is at least 100 μm.

[0225] (Example 88) The assembly according to any one of Examples 81 to 87, wherein the second region of the second layer is configured to be detachably coupled to a fiber array.

[0226] (Example 89) The assembly according to any one of Examples 81 to 88, wherein the second region of the second layer further includes a reflector for changing the direction of the light beam transmitted from the second plurality of waveguides.

[0227] (Example 90) The assembly according to any one of Examples 81 to 89, wherein in a cross-section passing through a second region of the second layer, the second plurality of waveguides are arranged in a two-dimensional matrix.

[0228] (Example 91) An assembly, Multiple surface waveguides extending along the surface, A plurality of three-dimensional waveguides in a glass medium, wherein each of the plurality of three-dimensional waveguides is communicatively coupled to each of the plurality of surface waveguides, Output from the assembly, configured such that each of the plurality of three-dimensional waveguides is detachably coupled to each of the plurality of optical fibers, An assembly that includes this.

[0229] (Example 92) The assembly according to Example 91, wherein the output is on a glass medium.

[0230] (Example 93) The assembly according to Example 92, further comprising a mirror between the plurality of three-dimensional waveguides and the output, wherein the mirror is configured to deflect optical signals from each of the plurality of three-dimensional waveguides toward the output.

[0231] (Example 94) An assembly of any of Examples 91 to 93, wherein the plurality of surface waveguides are silicon waveguides on a silicon layer.

[0232] (Example 95) An assembly of any of Examples 91 to 94, wherein each of the plurality of three-dimensional waveguides is communically coupled to each of the plurality of surface waveguides by evanescent coupling.

[0233] (Example 96) The assembly according to Example 95, wherein the distance between one of the plurality of three-dimensional waveguides and each of the plurality of surface waveguides is 3 μm or less.

[0234] (Example 97) Any assembly from Examples 91 to 96, further comprising a bonding layer between the surface containing the plurality of surface waveguides and the glass medium.

[0235] (Example 98) A silicon layer and A plurality of first waveguides extending along the surface of the silicon layer, The glass layer on the surface of the silicon layer, A second plurality of waveguides within the glass layer, each of the second plurality of waveguides being evanescently coupled to one of the first plurality of waveguides, An assembly that includes this.

[0236] (Example 99) The assembly of Example 98, wherein the evanescent coupling is located within a first region of the glass layer, and within a second region of the glass layer, one of the second plurality of waveguides is located on another of the second plurality of waveguides.

[0237] (Example 100) The assembly of Example 99, wherein, within the second region of the glass layer, the first portion of the second plurality of waveguides is further away from the silicon layer than the second portion of the second plurality of waveguides.

[0238] The above description of illustrated implementations of the Disclosure, including those described in the Abstract, is not intended to be exhaustive or to limit the Disclosure to the exact form disclosed. While specific implementations of the Disclosure and examples of the Disclosure are described in this Specification for illustrative purposes, various equivalent modifications are possible within the scope of the Disclosure, as will be apparent to those skilled in the art. These modifications may be made to the Disclosure in light of the above detailed description. [Explanation of Symbols]

[0239] 102 Support structure 104 Optical materials 106 Mirror 108 Housing Materials 110 Bonding materials 112 Optical Fibers 160 optical layer 300 Vertical Optical Coupler 310 Lens array layer 315, 317 lenses 325 Reflector 330 Interface 340 Photonic Integrated Circuits (PICs) 350 Fiber-Equipped Unit (FAU) 360 optical layer

Claims

1. A photonic integrated circuit (PIC), An optical channel extending in the first direction, A reflective portion located at the end of the optical channel and having a surface inclined with respect to the first direction, The lens above the reflective part, A PIC comprising the reflective portion, wherein the optical path from the reflective portion to the lens is perpendicular to the first direction.

2. The PIC according to claim 1, further comprising a substrate extending across a plane, wherein the first direction is parallel to the plane of the substrate.

3. The PIC according to claim 1, wherein the reflective portion includes a high-reflectivity coating along the front surface.

4. The PIC according to claim 1, wherein the reflective portion includes a total internal reflection (TIR) ​​reflective portion along the front surface.

5. The PIC according to claim 1, wherein the lens is a convex lens.

6. The PIC according to claim 1, wherein the lens is configured to collimate light moving from the reflecting portion through the lens.

7. The PIC according to claim 1, wherein the optical channel is located in the first layer, the lens is located in the second layer, and the first layer is bonded to the second layer.

8. The PIC according to claim 1, wherein in a cross-section passing through the reflective portion, the optical channel, and the lens, the reflective portion has a parallelogram shape.

9. The PIC according to claim 1, wherein in a cross-section passing through the reflective portion, the optical channel, and the lens, the reflective portion is trapezoidal.

10. The PIC according to claim 9, wherein the reflective portion has a second surface on the opposite side of the inclined surface, and the second surface is perpendicular to the first direction.

11. The PIC according to claim 10, wherein the reflective portion has a second surface opposite to the inclined surface and an upper surface between the inclined surface and the second surface, and the first angle between the inclined surface and the upper surface is within 10° of the second angle between the second surface and the upper surface.

12. The PIC according to any one of claims 1 to 11, wherein the reflective portion includes a reflective material on at least one side surface of a non-reflective internal material.

13. A photonic integrated circuit (PIC) assembly, The first layer, Multiple optical channels extending in the first direction, A plurality of reflective portions are arranged at each end of the optical channel, The first layer includes, A lens array on the first layer, wherein the lens array includes a plurality of lenses disposed on corresponding reflective portions among the plurality of reflective portions, A PIC assembly that includes this.

14. The PIC assembly according to claim 13, wherein the optical path from one of the plurality of reflectors to the corresponding one of the plurality of lenses is perpendicular to the first direction.

15. The PIC assembly according to claim 13, wherein the first portion of the plurality of lenses is arranged along a first line, the second portion of the plurality of lenses is arranged along a second line, and the first line is parallel to the second line and offset with respect to the second line.

16. The PIC assembly according to any one of claims 13 to 15, wherein the lens is a convex lens formed in a layer of silicon.

17. It is an assembly, An array of convex lenses arranged at the input to the assembly, wherein the convex lenses are arranged in at least two rows, An array of optical fibers, wherein one input of the optical fiber is located at one focal point of the array of convex lenses, An assembly that includes this.

18. The assembly according to claim 17, wherein one of the optical fibers is bent at a 90° angle.

19. The assembly according to claim 17, further comprising a ventilation hole on the bent portion of the optical fiber, wherein the ventilation hole extends in the direction of the optical fiber at the input portion of the optical fiber.

20. The assembly according to any one of claims 17 to 19, wherein the assembly is detachable from a second component, and the second component includes a plurality of optical outputs having a plurality of second convex lenses arranged in at least two rows.

21. It is an assembly, A layer of the medium for transmitting optical signals, An array of curved mirrors on the aforementioned layer, wherein one of the curved mirrors is configured to deflect a beam moving through the aforementioned layer, An array of optical fibers on a portion of the aforementioned layer, wherein each of the optical fibers has an input configured to receive a beam deflected from a corresponding one of the curved mirrors, An assembly that includes this.

22. The assembly according to claim 21, wherein the assembly is configured to be attached to and removed from a second assembly, and the second assembly is configured to transmit optical signals.

23. The assembly according to claim 22, wherein the second assembly includes a plurality of lenses having an arrangement corresponding to the array of curved mirrors.

24. The assembly according to claim 22, wherein the optical signal transmitted by the second assembly is an expanded beam.

25. The assembly according to any one of claims 21 to 24, wherein the array of curved mirrors is configured to receive a beam having a beam dimension of at least 5 μm.

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