Individually defined optical elements for use in an optical interconnect module

Abstract

An individually aligned optical element is incorporated in an optical interconnect module to enable efficient optical communication between an electrooptic component and an optical waveguide. The individually aligned optical element is defined, potentially using laser processing or additive manufacturing, within or on a surface of a transparent carrier to which the electrooptic component is mounted or within and / or on a surface of an optical block, which is arranged to attach to the transparent carrier. The individually aligned optical element is defined relative to either an active area of the electrooptic component or a core of an optical waveguide. There may be a plurality of active areas and optical waveguides, and each active area and optical waveguide has a corresponding optical element which is individually aligned, enabling high coupling efficiency and potentially providing features like collimated beams for enhanced assembly tolerance.

Description

INDIVIDUALLY DEFINED OPTICAL ELEMENTS FOR USE IN AN OPTICAL INTERCONNECT MODULECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to US Prov. App. No. 63 / 638,175 filed on April 24, 2024, US Prov. App. No. 63 / 672,967 filed on July 18, 2024 and US Prov. App. No. 63 / 760,078 filed on February 18, 2025, all of which are incorporated herein by reference in their entireties.TECHNICAL FIELD

[0002] The present disclosure relates to an arrangement and method of establishing efficient optical coupling between an electrooptic component and an optical waveguide in an optical interconnect module.BACKGROUND

[0003] Optical communication channels, using modulated light signals, may be used to rapidly and reliably transmit information in a variety of applications such as fiber optic communication networks, server farms, or computer systems.

[0004] Optical fiber networks have advantages over other types of networks such as electrically conductive cable-based networks. Many existing electrically conductive cable networks operate at near maximum possible data transmission rates and at near maximum possible distances for copper wire cable technology. Fiber optic networks may be used to reliably transmit data at higher data rates over further distances than is possible with copper cable networks.

[0005] Computer systems employing high speed optical interconnect modules may provide improved performance when compared to other computer systems. The performance of some computer systems can be restricted by the rate that computer processors can access memory or communicate with other components in the computer system. The restriction can be due, in part,to the physical limitations of data interconnects such as electrical connections. For example, electrical pins with a particular size and / or surface area that may be used in electrical connections may only be capable of transmitting a specific data transfer rate, and in turn this may limit the maximum bandwidth for data signals. In some circumstances, such connections may result in bottlenecks when the maximum bandwidth of connections becomes a performance limiting factor. High speed optical interconnect modules using light signals may permit transmission of information at increased data rates to decrease or eliminate such bottlenecks.

[0006] Although modulated light signals may be used to transmit data at increased data rates in fiber optic networks, computer systems or other applications, almost all memory, switching, and processing components of such systems use electrical signals. Accordingly, optical interconnect modules, which connect various elements within the network may incorporate electrooptic assemblies that convert electrical signals to optical signals, convert optical signals to electrical signals, or convert both electrical signals to optical signals and optical signals to electrical signals. A component of an electrooptic assembly is an optical engine, which includes an electrooptic (E / O) component, such as a laser, photodetector, or photonic integrated circuit, that provides optical-to- electrical and / or electrical-to-optical conversion in high-speed communication systems. The optical interconnect module may further include a microcontroller that controls operation of the optical engine. Preferably the optical interconnect module is easily integrated into a computer or communication system from an electrical, mechanical and thermal standpoint. Examples of optical interconnect modules include packages compliant with multi-source agreement standards such as QSFP, QSFP-DD, OSFP, COBO, and many others. Optical interconnect modules may be mounted on a front panel of an electronics rack, adjacent a processing element mid-board on a host circuit board, or co-packaged with a processing element on a processing element package substrate.

[0007] The optical interconnect module may be a transmitter, a receiver, or a transceiver. In a transmitter, the optical interconnect module converts electrical signals received from an electrical component into optical signals. In a receiver, the optical interconnect module converts received optical signals into electrical signals that are transmitted to an electrical component. In atransceiver, the optical interconnect module both converts electrical signals into optical signals and converts optical signals into electrical signals.

[0008] Components typically included in the optical interconnect module, such as E / O components, like a laser, photodetector, and photonic integrated circuit, and associated electrical elements like a laser driver and transimpedance amplifier (TIA) may be available with either wirebond pads configured to make a wirebond electrical connection to an adjacent electrical element or with flip-chip pads configured to make a flip-chip electrical connection to an underlying substrate. It is generally easier to maintain good signal integrity at high rates with a flip-chip electrical connection as compared to a wirebond connection, since the path length between the connected electrical pads is shorter. In some cases, component availability or component cost may dictate which type of electrical connection is used in the optical interconnect module. In the wirebond arrangement, the laser / photodetector is generally mounted on a substrate such that the wirebond pads and optically active area of the laser / photodetector face away from an underlying substrate. In the flip-chip arrangement, the laser / photodetector is generally mounted on a substrate such that the flip-chip pads and optically active area of the laser / photodetector face towards an underlying substrate. The architecture of an optical interconnect module using flip-chip components is thus typically different from a module using wirebond components. The present application describes an optical interconnect module that uses at least some flip-chip components in the optical engine.SUMMARY

[0009] According to a first aspect, a carrier subassembly is provided. The carrier subassembly comprises a transparent carrier having a first major surface and an opposed second major surface; an electrooptic component having an active area, wherein the electrooptic component is mounted to the first major surface; and an internal optical element situated within the transparent carrier between the first and second major surfaces, wherein the internal optical element is optically aligned with the active area of the electrooptic component. In some embodiments, the internal optical element has a spatially varying index of refraction and may be a diffractive optical element (e.g., a Fresnel zone plate), a refractive optical element, or a combination thereof. In variousembodiments, for a transmit channel, the internal optical element is configured to reduce the divergence of or collimate an optical beam emitted by the active area, potentially orienting its optical axis perpendicular to the second major surface within a tolerance. In some embodiments, for a receive channel, the internal optical element is configured to focus an incident optical beam onto the active area. In various embodiments, the carrier subassembly may further comprise a refractive lens on the second major surface, or the internal optical element may comprise multiple elements in series or be configured to pick-off a portion of a transmitted beam. In some embodiments, the electrooptic component may be a plurality of electrooptic components (e.g., multiple lasers / photodetectors, or a PIC and photodetector), each potentially having an individually aligned internal optical element. In various embodiments, the refractive index profile of the internal optical element may vary in three dimensions, potentially determined using artificial intelligence. In some embodiments, the transparent carrier comprises multiple bonded substrates (e g., a first substrate forming the first surface with superior mechanical properties and a second substrate forming the second surface containing the optical element), and an alignment mark may be situated on or beneath the second maj or surface, potentially written concurrently with the optical element.

[0010] According to a second aspect, an optical coupling assembly is provided. The optical coupling assembly comprises a transparent carrier having a first major surface and an opposed second major surface; an electrooptic component having an active area mounted to the first major surface and configured to emit an optical beam through the transparent carrier or detect an optical beam transmitted through the transparent carrier; an internal optical element situated within the transparent carrier between the first and second major surfaces, wherein the internal optical element is optically aligned with the active area of the electrooptic component; an optical block mounted on the second major surface; and an optical waveguide in optical communication with the active area. In some embodiments, the optical beam propagates through the optical block, and the optical waveguide (which may be an optical fiber) is mounted to the optical block. In various embodiments, the assembly may include a refractive lens or a reflective surface situated on a face of the optical block. In some embodiments, the optical beam is collimated between the first major surface and the optical block. In various embodiments, the internal optical element picks-off a portion of the beam, or it may be a diffractive or refractive element, or a combination. In someembodiments, the transparent carrier comprises multiple bonded substrates. In various embodiments, alignment marks situated on or beneath the second major surface aid in positioning the optical block, and these marks may be written concurrently with the internal optical element.

[0011] According to another aspect, an optical interconnect module is provided. The optical interconnect module comprises a transparent carrier having a first major surface and an opposed second major surface; and an internal optical element situated within the transparent carrier between the first and second major surfaces. In some embodiments, the module further comprises an electrooptic component mounted to the first major surface and arranged to emit or detect an optical beam through the transparent carrier and aligned with the internal optical element. In various embodiments, the internal optical element comprises two internal optical elements arranged in series, or a refractive lens is formed on the second major surface of the transparent carrier. In some embodiments, the internal optical element picks-off a portion of an optical beam, which may be sampled by a monitor photodiode. In various embodiments, the module includes a plurality of transmit and / or receive channels, and the electrooptic component may be a plurality of components (e.g., laser die, photodetector die, photonic integrated circuits). In some embodiments, each channel's internal optical element is individually aligned with its corresponding electrooptic component. In various embodiments, the internal optical element may be diffractive (e.g., Fresnel zone plate), refractive, or a combination, potentially with a 3D refractive index profile determined using Al. In some embodiments, the transparent carrier comprises multiple bonded substrates, and an alignment mark may be present on or beneath the second surface to help position an optical block, potentially written concurrently with the optical element.

[0012] According to yet another aspect, a method of assembling a carrier subassembly is provided. The method comprises mounting an electrooptic component on a first major surface of a transparent carrier, wherein the electrooptic component has an active area which is configured to emit or detect an optical beam that propagates through the transparent carrier; aligning a processing head of a laser processing tool with the active area; and defining an internal optical element within the transparent carrier, wherein the internal optical element is in optical alignment with the active area of the electrooptic component. In some embodiments, the electrooptic component has a plurality of active areas, and a corresponding internal optical element is individually defined foreach. In various embodiments, alignment may occur with the active area energized or de-energized (e.g., aligning to a contact ring). In some embodiments, defining the element involves scanning a focal spot of the laser tool. In various embodiments, the defined element collimates an emitted beam (if a laser) or focuses a received beam (if a photodetector). In some embodiments, the internal optical element is diffractive (e.g., Fresnel zone plate), refractive, or a combination. In various embodiments, the transparent carrier may comprise multiple bonded substrates, and an alignment mark may be written by the laser tool during the same step as the optical element.

[0013] According to another aspect, a method of assembling a carrier subassembly is provided. The method comprises mounting an electrooptic component having a plurality of active areas on a first major surface of a transparent carrier, wherein each active area of the plurality of active areas is configured to emit or detect a corresponding optical beam that propagates through the transparent carrier; aligning a processing head of a laser processing tool with a first active area of the plurality of active areas; defining a first internal optical element within the transparent carrier using the laser processing tool, wherein the first internal optical element is in optical alignment with the first active area of the electrooptic component; and repeating the aligning and defining steps for each active area of the plurality of active areas. In some embodiments, the electrooptic component is a laser, and each corresponding optical beam emitted is collimated by its respective internal optical element. In various embodiments, each collimated beam has an optical axis oriented perpendicular to a second major surface of the transparent carrier within a manufacturing tolerance. In some embodiments, the internal optical element is diffractive (e.g., Fresnel zone plate), refractive, or a combination. In various embodiments, the transparent carrier comprises multiple bonded substrates, and an alignment mark may be written by the laser tool during the same step as the optical element.

[0014] According to yet another aspect, a carrier subassembly is provided. The carrier subassembly comprises a transparent carrier having a first major surface and an opposed second major surface; an electrooptic component having an active area, wherein the electrooptic component is mounted to the first major surface; and a surface optical element situated on at least one of the first or second major surfaces, wherein the surface optical element is optically aligned with the active area of the electrooptic component. In some embodiments, the electroopticcomponent has a plurality of active areas and there are a plurality of surface optical elements, wherein each surface optical element is individually defined based at least in part on the position of its corresponding active area.

[0015] According to another aspect, a method of assembling a carrier subassembly is provided. The method comprises defining a plurality of optical elements between or on a first major surface or an opposed second major surface of a transparent carrier; aligning a placement head of a die bonding tool with the plurality of optical elements; and mounting an electrooptic component having a plurality of active areas on the first major surface of the transparent carrier with the placement head, wherein each active area of the plurality of active areas is configured to emit or detect a corresponding optical beam that propagates through the transparent carrier and each of the plurality of active areas is in optical alignment with each of the plurality of optical elements. In some embodiments, the optical elements are defined prior to mounting the electrooptic component.

[0016] According to yet another aspect, an optical block subassembly is provided. The optical block subassembly comprises an optical block, wherein the optical block has a bottom surface and a side surface configured to transmit an optical beam; a plurality of optical waveguides affixed to the optical block; and a plurality of optical elements, wherein each of the plurality of optical elements is associated with a corresponding optical waveguide and a location of each of the plurality of optical elements is individually defined at least in part by a position of each of the optical waveguides. In some embodiments, a processing tool determines the position of each optical waveguide and defines the associated optical element location accordingly. In various embodiments, each optical element is defined on a surface (e.g., bottom, side, or a reflective surface) by additive manufacturing (e.g., forming a refractive lens or curved mirror) or by inducing a spatially localized refractive index change within the block. In some embodiments, the optical waveguides form an optical fiber ribbon cable, and the element location may also depend on an alignment mark or feature on the optical block.

[0017] According to another aspect, a method of assembling an optical block subassembly is provided. The method comprises affixing a plurality of optical waveguides on an optical block; aligning a processing head of a processing tool with a first optical waveguide of the plurality ofoptical waveguides; defining a first optical element within or on a surface of the optical block using the processing tool, wherein the first optical element is in optical alignment with the first optical waveguide; and repeating the aligning and defining steps for each optical waveguide of the plurality of optical waveguides. In some embodiments, defining the optical element involves scanning a focal spot of a laser processing tool. In various embodiments, defining involves forming a curved mirror on a reflective surface or a refractive lens on a bottom or side surface via an additive manufacturing process.

[0018] According to yet another aspect, an optical interconnect module is provided. The optical interconnect module comprises a carrier subassembly, wherein the carrier subassembly comprises an electrooptic element mounted to a transparent substrate; an optical block subassembly, wherein an optical waveguide is affixed to the optical block subassembly; and an optical element, wherein the optical element is configured to help optically couple an optical beam between the electrooptic element and the optical waveguide, and the optical element is defined based at least in part on a position of the electrooptic element or the optical waveguide. In some embodiments, the optical element is located on a surface of or within the transparent substrate, or on a surface of or within the optical block of the optical block subassembly. In various embodiments, there are pluralities of electrooptic elements, waveguides, and optical elements, each coupling an associated pair, and the optical element(s) are defined using additive manufacturing or laser processing. In some embodiments, mating alignment features on the carrier and block subassemblies facilitate optical alignment, and these features may be defined, for example, by additive manufacturing. In various embodiments, the optical element can be a refractive lens, a curved mirror, or an element defined by internal refractive index change, potentially individually defined based on the active area position.

[0019] According to another aspect, an optical coupling assembly is provided. The optical coupling assembly comprises a transparent carrier having a first major surface and an opposed second major surface; an electrooptic component having an active area mounted to the first major surface and configured to emit an optical beam through the transparent carrier or detect an optical beam transmitted through the transparent carrier; an optical block mounted on the second major surface; a core of an optical waveguide in optical communication with the active area; and anoptical element situated between the electrooptic component and the optical waveguide, wherein a location of the optical element is based at least in part on a position of the active area or the core of the optical waveguide. In some embodiments, there are pluralities of electrooptic components, waveguides, and corresponding optical elements. In various embodiments, additive manufacturing or laser processing is used to define each optical element.

[0020] According to yet another aspect, an optical block subassembly is provided. The optical block subassembly comprises an optical block, wherein the optical block has a bottom surface and a side surface configured to transmit an optical beam; an alignment feature on the side surface configured to mate with an attachable / detachable optical fiber cable; and a plurality of optical elements, wherein each of the plurality of optical elements is configured to be associated with a corresponding optical waveguide of the attachable / detachable optical fiber cable and a location of each of the plurality of optical elements is individually defined at least in part by a position of the alignment feature. In some embodiments, these optical elements may be defined within or on a surface of the optical block to optimize coupling with the waveguides in the detachable cable.

[0021] According to another aspect, an optical coupling assembly is provided. The optical coupling assembly comprises a transparent carrier having a first major surface and an opposed second major surface; a plurality of electrooptic components mounted to the first major surface, each electrooptic component having an active area; and a plurality of internal optical elements situated within the transparent carrier between the first and second major surfaces, wherein each internal optical element is individually aligned with a corresponding active area of the plurality of electrooptic components, such that each internal optical element's position is customized based on the position of its corresponding active area independent of the positions of other internal optical elements. In some embodiments, these internal optical elements may be diffractive or refractive.

[0022] According to yet another aspect, a method of manufacturing an optical coupling assembly is provided. The method comprises mounting a plurality of electrooptic components to a first major surface of a transparent carrier, each electrooptic component having an active area; for each active area of the plurality of electrooptic components: individually aligning a processing head of a laser processing tool with that active area; and defining an internal optical element within the transparentcarrier at a position optimized for that specific active area independent of the positions of other internal optical elements, wherein the resulting plurality of internal optical elements are each individually customized for their corresponding active areas without compromise for alignment with other active areas. In various embodiments, this process uses laser-induced refractive index changes.

[0023] According to another aspect, an optical coupling assembly is provided. The optical coupling assembly comprises a transparent carrier having a first surface and an opposed second surface; a plurality of electrooptic components mounted to the first surface and spaced apart from each other in a spaced array, each electrooptic component having multiple active areas; an optical block mounted to the second surface of the transparent carrier; a plurality of optical waveguides supported by the optical block; and a plurality of optical elements situated within the transparent carrier between the first and second surfaces, wherein each optical element is individually written and aligned with respect to a corresponding active area after mounting of the electrooptic components and before mounting of the optical block, and wherein optical elements associated with transmit channels provide collimated optical beams in a region between the transparent carrier and optical block to accommodate lateral positioning tolerances between the transparent carrier and optical block while maintaining optical coupling efficiency. In some embodiments, this individual alignment ensures optimal collimation and pointing direction for each transmit beam.

[0024] According to yet another aspect, a method of manufacturing an optical coupling assembly is provided. The method comprises mounting a plurality of electrooptic components to a first surface of a transparent carrier, each electrooptic component having multiple active areas; for each active area: determining a position of the active area; aligning a laser processing tool with the determined position; writing a customized optical element within the transparent carrier between the first surface and an opposed second surface using the laser processing tool, wherein, for active areas corresponding to transmit channels, the customized optical element is configured to provide a collimated optical beam; writing an alignment feature on or near the second surface of the transparent carrier using the same laser processing tool while maintaining alignment with the active area; and mounting an optical block supporting optical waveguides to the second surface of the transparent carrier using the alignment features to achieve registration between the opticalblock and transparent carrier. In some embodiments, writing the alignment feature concurrently with the optical element ensures high precision registration.

[0025] According to another aspect, an optical interconnect module is provided. The optical interconnect module comprises a carrier subassembly comprising a plurality of active areas; an optical block subassembly comprising a plurality of optical waveguides, wherein each of the plurality of active areas is in optical alignment with an associated optical waveguide of the plurality of optical waveguides; and a plurality of individually defined optical elements, wherein each individually defined optical element of the plurality of optical elements is in optical alignment with an active area and its associated optical waveguide and a position of each individually defined optical element is based on a position of its associated active area independent of the position of other active areas. In some embodiments, the active areas are on an electrooptic component flip- chip mounted to a transparent carrier within the carrier subassembly. In various embodiments, alignment between subassemblies uses mating alignment features, potentially with an intermediate optical block guide, and the carrier feature may be fabricated concurrently with the optical elements. In some embodiments, the individually defined elements are within / on the carrier, within / on the block, or both.

[0026] According to yet another aspect, a wafer assembly is provided. The wafer assembly comprises a plurality of cojoined individual transparent carrier subassemblies, each individual transparent subassembly comprising a plurality of active areas; and a plurality of individually defined optical elements, wherein each individually defined optical element of the plurality of optical elements is in optical alignment with an active area of the plurality of active areas and a position of each individually defined optical element is based on a position of its associated active area independent of the position of other active areas. In some embodiments, electrooptic components are mounted across the wafer before the optical elements are defined, prior to singulation.

[0027] According to another aspect, a method of manufacturing a plurality of carrier subassemblies is provided. The method comprises providing a wafer comprising a transparent material, the wafer defining a plurality of distinct carrier subassembly sites; at each of the pluralityof distinct carrier subassembly sites on the wafer: i) mounting at least one electrooptic component having an active area to a first major surface of the wafer; and ii) defining at least one optical element within the wafer or on a second major surface of the wafer, the optical element being optically aligned with the active area; and subsequently singulating the wafer to separate the plurality of carrier subassemblies, each comprising the at least one electrooptic component and the at least one optical element defined at its respective site. In some embodiments, the method further comprises defining at least one alignment feature at each site using the same processing tool used to define the optical element.

[0028] According to yet another aspect, a method of aligning an optical block subassembly with a carrier subassembly is provided. The method comprises providing the carrier subassembly with a first alignment feature on its top surface; providing the optical block subassembly with a second alignment feature on its bottom surface; providing an optical block guide with a bottom guide feature mating to the first alignment feature and a top guide feature mating to the second alignment feature; engaging the carrier subassembly with the bottom guide feature; and engaging the optical block subassembly with the top guide feature, thereby aligning the subassemblies via the guide. In some embodiments, at least one alignment feature protrudes and the corresponding guide feature is a receiving slot.

[0029] According to another aspect, an optical block guide for aligning an optical block subassembly with a carrier subassembly is provided. The optical block guide comprises a body formed of a transparent material; a top surface having at least one top alignment feature configured to mechanically register with a corresponding alignment feature on a bottom surface of the optical block subassembly; and a bottom surface having at least one bottom alignment feature configured to mechanically register with a corresponding alignment feature on a top surface of the carrier subassembly. In some embodiments, the top and bottom alignment features are configured to engage with mating features on the respective subassemblies.

[0030] According to yet another aspect, an optical coupling assembly is provided. The optical coupling assembly comprises a transparent carrier having a first surface and an opposed second surface; a plurality of electrooptic components mounted to the first surface in a spaced array, eachhaving multiple active areas; an optical block mounted to the second surface; a plurality of optical waveguides affixed to the optical block; and a plurality of optical elements situated within or on a surface of the optical block, wherein each optical element is individually defined and aligned with respect to a corresponding optical waveguide after the waveguides are affixed, and each optical element's location is customized based on its corresponding waveguide's position independent of others, maintaining coupling efficiency despite waveguide position variations. In some embodiments, these block-based elements include refractive lenses or curved mirrors.

[0031] According to another aspect, an optical coupling assembly is provided. The optical coupling assembly comprises a transparent carrier having a first surface and an opposed second surface; a plurality of electrooptic components mounted to the first surface in a spaced array, each having multiple active areas including receive channels; an optical block mounted to the second surface; a plurality of optical waveguides supported by the optical block; and a plurality of optical elements situated within the transparent carrier between the first and second surfaces, wherein each optical element is individually written and aligned with a corresponding active area after electrooptic component mounting and before optical block mounting, and wherein optical elements for receive channels are configured to focus an incoming optical beam from the corresponding waveguide onto the receive active area, maintaining coupling efficiency despite electrooptic component positioning variations. In various embodiments, these focusing elements are internal diffractive or refractive elements.

[0032] According to another aspect, a carrier subassembly is provided. The carrier subassembly comprises a transparent carrier having first and second major surfaces, and an electrooptic component mounted relative to the first major surface. The electrooptic component includes an active area and its own substrate. The electrooptic component is configured such that the optical signal path between the active area and the transparent carrier passes through the substrate of the electrooptic component (e.g., a back-emitting VCSEL or back-receiving photodetector), this substrate being substantially transparent at the operating wavelength. The subassembly further includes at least one optical element situated within the transparent carrier or on its second major surface, wherein this optical element is optically aligned with the active area specifically via the signal path that traverses the substrate of the electrooptic component.

[0033] According to yet another aspect, a method of manufacturing an optical coupling assembly is provided. The method involves mounting an electrooptic component relative to a first major surface of a transparent carrier, where the electrooptic component is configured for optical signal transmission through its own substrate (which is transparent at the operating wavelength) between its active area and the transparent carrier. A processing head of a processing tool is then aligned with the active area, specifically accounting for the optical signal path through the substrate of the electrooptic component. Subsequently, the processing tool is used to define at least one optical element (e.g., internal or surface) within the transparent carrier or on its second major surface, ensuring the optical element is optically aligned with the active area via this specific signal path through the substrate of the electrooptic component.BRIEF DESCRIPTION OF DRAWINGS

[0034] FIG. 1 shows a perspective view of a bottom of an optical interconnect module with an exposed electrooptic component according to an embodiment of the present disclosure.

[0035] FIG. 2 shows a top surface of an electrooptic component according to an embodiment of the present disclosure.

[0036] FIG. 3 A is a cross-sectional view of a portion of a transmit channel of a carrier subassembly according to an embodiment of the present disclosure.

[0037] FIG. 3B is a cross-sectional view of a portion of a receive channel of a carrier subassembly according to an embodiment of the present disclosure.

[0038] FIG. 4A shows a cross-sectional view of a Fresnel zone plate according to an embodiment of the present disclosure.

[0039] FIG. 4B shows a top view of a Fresnel zone plate according to an embodiment of the present disclosure.

[0040] FIG. 5 shows an exemplary refractive index profile of a Fresnel zone plate according to an embodiment of the present disclosure.

[0041] FIG. 6 shows an exemplary refractive index profile of a 1 -dimensional grating according to an embodiment of the present disclosure.

[0042] FIG. 7 is a cross-sectional view of a carrier subassembly according to an embodiment of the present disclosure.

[0043] FIG. 8A shows a cross-sectional view of an internal refractive optical element according to an embodiment of the present disclosure.

[0044] FIG. 8B shows a top view of an internal refractive optical element according to an embodiment of the present disclosure.

[0045] FIG. 9 shows an optical coupling assembly according to an embodiment of the present disclosure.

[0046] FIG. 10 is a cross-sectional view of a carrier subassembly according to an embodiment of the present disclosure.

[0047] FIG. 11 is a cross-sectional view of a carrier subassembly according to an alternative embodiment of the present disclosure.

[0048] FIG. 12 is a cross-sectional view of a carrier subassembly according to an alternative embodiment of the present disclosure.

[0049] FIG. 13 is a cross-sectional view of a carrier subassembly according to another alternative embodiment of the present disclosure

[0050] FIG. 14 is a method of making a carrier subassembly according to an embodiment of the present disclosure.

[0051] FIG. 15 is a perspective view of a plurality of carrier subassemblies cojoined in a wafer prior to singulation subassembly according to an embodiment of the present disclosure.

[0052] FIG. 16 is a cross-sectional view of an optical block subassembly according to an embodiment of the present disclosure.

[0053] FIG. 17 illustrates an optical coupling assembly including an optical block guide according to an embodiment of the present disclosure

[0054] FIG. 18 illustrates a method of assembling an optical block subassembly according to an embodiment of the present disclosure.

[0055] FIG. 19 is an optical assembly according to an embodiment of the present disclosure.

[0056] FIG. 20 is a cross-sectional view of a composite optical block subassembly according to an embodiment of the present disclosure.

[0057] FIG. 21 is a cross-sectional view of a composite optical block subassembly according to an alternative embodiment of the present disclosure.

[0058] Like reference numbers and designations in the various drawings indicate like elements.DETAILED DESCRIPTION

[0059] The present disclosure can be understood more readily by reference to the following detailed description taken in connection with the accompanying figures and examples, which form a part of this disclosure. It is to be understood that this disclosure is not limited to the specificdevices, methods, applications, conditions or parameters described and / or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the scope of the present disclosure. Also, as used herein, the singular forms “a,” “an,” and “the” include “at least one” and a plurality. Further, reference to a plurality as used in the specification including the appended claims includes the singular “a,” “an,” “one,” and “the,” and further includes “at least one.” Further still, reference to a particular numerical value in the specification including the appended claims includes at least that particular value, unless the context clearly dictates otherwise.

[0060] The term “plurality”, as used herein, means more than one. A range of values may be expressed as including all values between a first particular value to a second particular value, including both the first and second values. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another example. All ranges are inclusive and combinable.

[0061] The term “substantially,” “approximately,” and derivatives thereof, and words of similar import, when used to described sizes, shapes, spatial relationships, distances, directions, and other similar parameters includes the stated parameter in addition to a range up to 10% more and up to 10% less than the stated parameter, including up to 5% more and up to 5% less, including up to 3% more and up to 3% less, including up to 1% more and up to 1% less.

[0062] It should be understood that terms such as top, bottom, up, down, right, left, sides, vertical, and horizontal are relative terms and the embodiments described herein can be used in any orientation.

[0063] FIG. 1 shows a perspective view of a bottom or first surface of an optical interconnect module 100 according to an embodiment of the present disclosure. The optical interconnect module 100 may be configured to mate with an optical fiber cable 102, which may be permanently affixed to the module 100 (commonly referred to as pigtailed to the module) or may be separable from the module 100. The optical fiber cable 102 may be a ribbon cable having a plurality of optical waveguides 112 (later shown in Figs. 9, 15 and 17-19), for example twelve optical fibersdispersed in a row along a lateral or y-direction. The optical waveguides in the optical fiber cable may be oriented along a longitudinal or z-direction. The optical waveguides may be single mode optical fibers or multimode optical fibers. There may be more than one optical fiber cable 102 attached to the optical interconnect module 100, for example, there may be two ribbon cables, one ribbon cable stacked above the other ribbon cable (not shown in FIG. 1). In FIG. 1 several elements of the module 100 have been removed to expose an electrooptic component 125. FIG. 1 shows four electrooptic components; however, there may be any number of electrooptic components 125. In this embodiment, the optical interconnect module 100 is an optical transceiver having two types of electrooptic components 125, a laser 124, which serves as the basis of a transmitter, and a photodetector 126, which serves as the basis of a receiver. In other embodiments, the optical interconnect module 100 may be a transmitter having no receiver elements or a receiver having no transmitter elements. Collectively the laser 124 and photodetector 126 may be referred to as electro-optic (E / O) components 125, since they transform an electrical signal into an optical signal or an optical signal into an electrical signal. Both the laser 124 and photodetector 126 may be comprised of a plurality of individual lasers and photodetectors formed on a single die, each individual laser supporting a transmit channel and each individual photodetector supporting a receive channel. The electrooptic components 125 may be flip-chip mounted to a transparent carrier or substrate 116. The electrooptic components 125 may be mounted to the transparent carrier 116 using a placement head of a processing tool, such as a die bonding tool. Optical transmit and receive signals are coupled out of and into the E / O components 125 through the transparent carrier 116. The transparent carrier 116 may be formed from glass or any suitable substrate transparent at the optical wavelengths transmitted and received by the E / O components 125.

[0064] FIG. 2 shows a top surface 130 of an E / O component 125 according to an embodiment of the present disclosure. The top surface 130 may be considered the active face of the E / O component, since this surface contains the emitting / receiving area and the associated electrical connections to that area. The E / O component 125 may be a laser 124, such as a VCSEL (Vertical Cavity Surface Emitting Laser) or a photodetector. The laser 124 may have a plurality of individual emitting elements 132. In the exemplary laser 124 shown in FIG. 2 there are four individual emitting elements 132; however, there may be any number of individual emitting elements 132. Each individual emitting element 132 may include an active area 134 that transforms an electricalinput into an optical output. Surrounding the active area 134 may be an electrically conductive contact ring 136. The contact ring 136 may completely surround the active area 134 as shown in FIG. 2 or it may have one or more discontinuities. In either case it may be said that the contact ring 136 is aligned with and surrounds the active area 134. The active area 134 may be well centered within the contact ring 136, for example, the active area 134 may be centered to within ±0.1, 0.2, 0.5 or 1 microns. The contact ring 136 is configured to inject current into the active area 134 which causes emission of an optical beam from the active area 134. The active area 134 may an emitting aperture of a VCSEL. Each individual emitting element 132 may also have a first contact pad 138 and second contact pad 140. The first and second contact pads may be flip-chip pads configured for flip-chip mounting of the E / O component 125. The first contact pad 138 may be in electrical communication with the contact ring 136 through an electrically conductive trace 142 running between them. The second contact pad 140 is also in electrical communication with the active area 134 through appropriate doping of the material underlying the top surface 130 and not visible in FIG. 2. The first and second contact pads 138, 140 may be suitable for flip-chip mounting of the laser 124. The contact ring 136, first contact pad 138, second contact pad 140, and electrically conductive trace 142 may also be formed by patterned metallization of the top surface 130 through a photolithographic process. Since all these elements are metal, these elements are readily visible. The laser 124 may be formed on a GaAs or InP substrate.

[0065] A top surface of a photodetector may be similar in appearance to that of the top surface 130 of the laser 124 shown in FIG. 2. Both the laser 124 and a photodetector may have contact ring 136 surrounding the active area 134. A difference between them may be the layout of the contact pads 138 and 140 and electrically conductive patterning on the top surface. The active areas of laser and photodetector components may also have different physical dimensions that impact coupling tolerances. For laser components, the active emitting area is typically around 10 microns in diameter, while photodetector active areas may be larger, for example, 25-30 microns in diameter. This difference in active area size results in different alignment tolerances between transmit and receive channels, with photodetector coupling generally being more tolerant to misalignment due to the larger active area. This difference in alignment tolerance may influence the positioning of transmit and receive channels within the optical interconnect module.

[0066] The photodetector transforms an optical input signal into an electrical output signal. Current is generated by absorption of an incoming optical beam in the active area 134 and collected by the contact ring 136. The photodetector may be formed on a Si, GaAs, or InGaAs substrate.

[0067] Returning to FIG. 1, there may be multiple E / O components 125 flip-chip mounted on the transparent carrier 116 in the optical interconnect module 100. Two lasers 124 and photodetectors 126 are shown in FIG. 1 so there are a total of four E / O components 125 in this embodiment. Since each E / O component 125 may have four individual electrooptic elements (emitters or receivers) (see FIG. 2) there are a total of sixteen optical channels, eight transmit channels and eight receive channels in the module 100 depicted in FIG. 1. In other embodiments there may be more or fewer optical channels and the optical channels may be apportioned differently between receiver and transmitter channels. Adjacent to each laser 124 there may be a laser driver 119 and adjacent to each photodetector 126 there may be a transimpedance amplifier (TIA) 122. Both the laser driver 119 and photodetector 126 may be flip-chip mounted to the transparent carrier 116. The flip-chip mounting may be by any known means, such as but not limited to thermo-compression bonding, thermo-sonic bonding, or solder. In flip-chip mounting, an active face of the E / O component 125 faces towards the transparent carrier 116. Collectively, the laser 124, photodetector 126, laser driver 119, TIA 122 and transparent carrier 116 to which they are mounted may be referred to as an optical engine, since these components handle conversion of a modulated, high-speed data signal from an optical to electrical signal or an electrical to optical signal. The laser 124 and laser driver 119 may be in electrical communication with each other through electrically conductive traces (not shown in FIG. 1) formed on the transparent carrier 116. The electrically conductive traces may be formed by a patterned metallization of a bottom surface of the transparent carrier 116. The transparent carrier 116 may be exposed through an opening or cutout in a printed circuit board 144. Mounted on the printed circuit board 144 may be a plurality of electrical components that are in electrical communication with the electrical traces on the transparent carrier 116. The transparent carrier 116 may include a redistribution layer (not visible in FIG. 1) that routes electrical signals between the laser 124, photodetector 126, laser driver 119, TIA 122, and printed circuit board 144.

[0068] The optical interconnect module 100 may be used as a component in a data transport or optical communication system. Nodes of the communication system, for example, a host and a target, may use a computer bus protocol to send data and auxiliary (control) signals over an optical link. For example, the optical interconnect module 100 may be used to form a data transport system that includes one of the optical interconnect modules coupled to each end of an optical link so that it controls the input and output and hence the transport of data over the optical link. The optical link can comprise any desired optical waveguide, but in an embodiment is a bundle or group of optical fibers, such as the optical fiber cable 102 depicted in FIG. 1. The information transported to / from the ends of the optical link can be sent and received using separate fibers. As noted above there may be fibers dedicated to transmission and fibers dedicated to reception. Each optical fiber may propagate a single data channel or multiple data channels may be multiplexed into a single fiber using wavelength division multiplexing. While the optical link described herein as an example includes an 8-channel full-duplex optical link using a single optical wavelength in each fiber, the embodiment is not so limited as the optical link may include any number of channels as appropriate to a configuration of the data transport system.

[0069] FIG. 3 A is a cross-sectional view of a transmit portion of a carrier subassembly 108 that may be incorporated into an optical interconnect module according to an embodiment of the present disclosure. An optical beam 104 may be emitted by the laser 124 in a transverse direction as part of a transmit channel 160. The laser 124 may be mounted to a first or bottom major surface 121 of the transparent carrier 116. A heat sink (not shown in FIG. 3A) may be situated beneath the laser 124 and may help to dissipate heat generated by the laser 124 during operation. The transparent carrier 116 has an opposed second or top major surface 117. The first and second major surfaces 121 and 117 may be flat. The optical beam 104 is emitted in a propagation direction 107 and is transmitted through the transparent carrier 116. An optical element 109 may be situated within the transparent carrier 116 between the first and second major surfaces 117, 121 in a path of the optical beam 104. The optical element 109 may be considered an internal optical element 106, since the first and second major surfaces 121 and 117 are not altered by formation of the internal optical element 106. The internal optical element 106 is thus formed in the bulk material of the transparent carrier 116, not on any surface of the transparent carrier 116. The internal optical element 106 may be formed by inducing a localized change in a refractive index in the transparentcarrier. The internal optical element 106 may be refractive or diffractive in nature. In an internal diffractive optical element, the refractive index spatial is modulated with multiple modulation periods across the optical beam 104, such as in a grating. In an internal refractive optical element, the refractive index spatial variation is more gradual, such as in a gradient refractive index (GRIN) lens. The optical element 109 may be optically aligned with an active area of the laser 124 (not visible in FIG. 3 A). The alignment may be achieved by visualization of the active area 134 or if the active area 134 cannot be directly visualized through visualization of the contact ring 136 or some other feature on the laser 124 (see FIG. 2) The optical element 109 may alter a wavefront of the optical beam 104 as it passes through the optical element 106, thereby changing a divergence of the optical beam 104. In particular, the internal optical element 109 may reduce the divergence of the optical beam 104 in a region above the top surface 117 of the transparent carrier 116. Advantageously, the optical element 109 may collimate the optical beam 104 emitted through the top surface 117 of the transparent carrier 116. The optical beam 104 may be considered collimated in a region along its propagation path within a Rayleigh length of a beam waist. It may be said that the optical element 109 is configured to collimate the optical beam 104 emitted by the active area of the laser 124. As well as collimating the optical beam 104, the optical element 109 may be aligned to ensure an optical axis 105 of the optical beam 104 emerging from the top surface 117 is oriented to be perpendicular to within a predefined (e.g. manufacturing) tolerance to the top surface 117. The predefined tolerance can be less than 0.05°, 0.1°, 0.2°, or 0.5°. The optical element 109 may also be considered to be an individually defined optical element, since its location and optical attributes may be customized based on a location and attributes of the laser 124.

[0070] An internal optical element 106 may also be used in a carrier subassembly 308 having a receive channel 162 in which the E / O component is a photodetector 126 as shown in FIG. 3B. The arrangement is as previously described in regard to FIG. 3 A only the propagation direction 107 of the optical beam 104 is reversed so that the propagation direction 107 is into the transparent carrier 116 along the transverse direction. In the case of a receive channel, the optical beam 104 may be collimated in a region adjacent the top surface 117 and above the internal optical element 106. The internal optical element 106 may then focus the optical beam 104 on to the active area of the photodetector 126. It may be said that the internal optical element 106 is configured to focus the optical beam 104 incident on the second or top major surface of the transparent carrier 116 on tothe active area of the photodetector. It should be appreciated that a carrier subassembly, such as the carrier subassembly incorporated into optical interconnect module 100 (see FIG. 1), can have both transmit and receive channels. In some embodiments, internal optical elements 106 in the transmit channels may be different than the internal optical elements 106 in the receive channels, while in other embodiments they may be the same.

[0071] The internal optical element 106, such as those shown in FIGS. 3A or 3B, may be formed by laser processing using a laser processing tool. Specifically, a laser, such as an ultrafast laser generating a train of picosecond or femtosecond long pulses may be focused into the transparent carrier 116. At regions at and / or near the focus, an intensity of the pulse may induce a permanent change in the optical properties of the material forming the transparent carrier 116. A magnitude of the permanent change may be proportional to an energy in each laser pulse of the processing beam pulse train. The permanent change may be a change in the index of refraction. Alternatively, the permanent change may be a change in the material absorption or scattering. By scanning the focal position of the processing laser beam emitted by the laser processing tool within the transparent carrier 116, the internal optical element 106 can be written or formed. It should be understood that certain laser processing techniques, such as those that build up material through polymerization processes, are considered forms of additive manufacturing as described further below. The pulse energy and focal spot size of the processing laser beam may be adjusted as well to tailor the optical properties of the internal optical element 106. It should be appreciated that other types of laser processing, for example, using crossed laser beams may be used to write or define the internal optical element 106. The crossed beams may give rise to an interference pattern, which may be used to define the internal optical element 106. In some embodiments, the internal optical element 106 may be a computer-generated hologram. Artificial intelligence may be used to determine the desired spatial variation of the refractive index and the laser processing parameters needed to generate the desired spatial variation in the refractive index that creates the internal optical element 106. The internal optical element 106 may be a blazed grating.

[0072] The spatial distribution and depth of refractive index modulation can be precisely controlled during the writing process. For laser-written optical elements, the magnitude of the permanent change may be proportional to the energy in each laser pulse. The processingparameters including pulse energy, focal spot size, and scanning pattern may be optimized for each optical element individually. This individual optimization allows each optical element to be customized for its specific channel, taking into account the position and characteristics of both the electrooptic component and the optical waveguide

[0073] In addition to the depth of refractive index modulation a thickness, or more generally a spatial distribution, of the refractive index modulation will also impact the differential phase shift acquired across a wavefront of the optical beam 104 as it propagates in a propagation direction 107 through the internal optical element 106. The spatial distribution of the refractive index modulation and the modulation depth can be varied in a coordinated manner to achieve a desired change in the optical beam 104 wavefront resulting in a collimated beam for the transmit channel 160 or a focused beam for the receive channel 162.

[0074] An example of a laser processing method is the SCRIBE (Subsurface Controllable Refractive Index via Beam Exposure) method described by Corey A. Richards, et. al. in a paper entitled “Hybrid achromatic microlenses with high numerical apertures and focusing efficiencies across the visible” published in Nature Communications (2023) 14:3119. This paper describes a method to induce a spatially localized refractive index variation in a transparent substrate. The method can produce both refractive and diffractive internal optical elements. The internal optical elements are formed in a PSiCh or PiS substrate, which is a porous SiCh or Si structure, respectively, in which the pores are filled with photoresist. The substrate is mechanically fragile and is attached to a fused silica substrate for subsequent processing and handling. A focused femtosecond laser is used to polymerize the photoresist by nonlinear polymerization at specific locations in the PSiCh or PiS. The nonlinear polymerization may be a two photon polymerization. The processing laser beam is scanned in a desired volumetric pattern to form internal optical elements. Unpolymerized photoresist is removed from the pores by developing the processed substrate. An advantage of the SCRIBE fabrication method is that the induced refractive index variation between the laser processed and unprocessed substrate may be large relative to other laser processing techniques. However, any laser processing method may be used to write or define the internal optical elements described herein.

[0075] The position of the laser processing beam may be controlled by a processing head of a laser processing tool. Specifically, the processing head may direct the laser processing beam so that the internal optical element is aligned with an active area of an E / O component. The internal optical element written by the laser processing tool is thus individually aligned with each active area.

[0076] The internal optical element 106 of FIGS. 3A-3B may be a diffractive internal optical element, such as a Fresnel zone plate 146 as shown in FIGS. 4A and 4B. Additionally, the optical element can be a refractive optical element, depending on the system requirements. In some embodiments, a combination of both diffractive and refractive optical elements may be used to improve or optimize optical performance.

[0077] FIG. 4A shows a cross-sectional view of the Fresnel zone plate 146 and FIG. 4B shows a top view of the Fresnel zone plate 146. A coordinate axis may be defined with the bottom surface 121 of the transparent carrier 116 being in a horizontal y-z plane and a vertical x-axis extending upward from the bottom surface 121 of the transparent carrier 116. The z-axis may define a longitudinal direction, the y-axis may define a lateral direction, and the x-axis may define a height or transverse direction. The x-axis may define a center of the Fresnel zone plate 146 and it may be radially symmetric about the x-axis. A vertical center of the Fresnel zone plate 146 may be a height, h, from the bottom surface 121 of the transparent carrier 116. The Fresnel zone plate 146 may include a series of concentric rings or zones of varying width. There may be two types of zones, a first zone type 148, and a second zone type 150, with each zone type having different optical properties. The first zone type may include a central zone 152. Advantageously, both the first and second zone types 148, 150 may be transparent, but have a different index of refraction, An. Having both zone types 148 and 150 transparent helps maximize optical transmission through the Fresnel zone plate 146. A zone height, hz, may be arranged such that an optical beam transmitted through the Fresnel zone plate 146 experiences a phase shift of approximately 7t between portions of the optical beam passing through the first zone 148 and those portions passing through the second zone 150. The width and spacing of the first and second zones 148, 150 may be chosen such that a diverging wavefront of an optical beam incident on the Fresnel zone plate is collimated by the Fresnel zone plate 146. Similarly, a collimated beam incident on the Fresnel zone plate 146 may be focused by the Fresnel zone plate. As previously disclosed, the Fresnelzone plate 146 may be situated between the top surface 117 and the bottom surface 121 of the transparent carrier 116.

[0078] As disclosed above in the description of FIGS. 4A and 4B the refractive index of the material forming the transparent carrier 116 may be permanently changed in a spatially localized manner having two zones with a different refractive index. For example, FIG. 5 depicts a representative refractive index profde 154 for the Fresnel zone plate depicted in FIGS. 4A and 4B. The refractive index profile 154 may vary in a modulated, stepwise manner from a base value, nb, which corresponds to the refractive index of the unprocessed material constituting the transparent carrier 116, to a processed value, nb+An. Here An represents a magnitude of the refractive index change induced by the laser processing. The refractive index change shown in FIG. 5 is positive, but the refractive index change in the processed zone may be negative.

[0079] It should be appreciated that the internal optical element 106 need not have two distinct zones with a different refractive index, but rather may consist of a discrete number of refractive index levels or a continuous variation in the refractive index across the internal optical element. Using a refractive index profile having multiple discrete levels or a continuous variation may result in an internal optical element 106 that is more efficient than an internal optical element 106 employing only a binary change in the refractive index. FIG. 6 depicts an exemplary index profile 154 having a continuous variation in the refractive index. This profile has a sinusoidal refractive index modulation as a function of the longitudinal position. The internal optical element 106 may have a uniform spacing, s, between successive maxima in the refractive index. The maximum magnitude of the refractive index change from its base value is Anmax. The refractive index may be uniform over the internal optical element in the lateral direction, such that the internal diffractive optical element forms a 1 -dimensional grating. Such an internal diffractive optical element may be used as a beam splitter to pick off part of the optical beam 104 (see FIG. 7). Generally, a grating will produce two picked-off beams, one on each side of the main optical beam 104, with the angle of the picked-off beam dependent on the grating spacing, s. A blaze or bias may be added to the refractive index profile 154 so that picked-off beams on opposite sides of the main beam have a different power level. It should be appreciated that the longitudinal scale may not be the same between FIG. 5 and FIG. 6.

[0080] FIG. 7 is a cross-sectional view of a carrier subassembly 108 according to an embodiment of the present disclosure having a plurality of optical elements in the transparent carrier 116. Many of the features of the carrier subassembly 108 depicted in FIG. 7 are similar to those described above relative to FIG. 3A and will not be repeated here for brevity. In addition to those features previously described, the carrier subassembly 108 may have a plurality of optical elements, such as two optical elements, a first optical element 106a and a second optical element 106b. The two optical elements 106a and 106b may be arranged in series, such that the optical beam 104 passes through both internal optical elements 106a and 106b. As depicted in FIG. 7 the first internal optical element 106a may collimate the optical beam 104 emitted by the laser 124. The first internal optical element 106a is shown as a Fresnel zone plate in FIG. 7, but in other embodiments may be an internal refractive optical element. The second internal optical element 106b may pick-off a portion of the optical beam 104 to form a picked-off optical beam 156. Preferably the second internal optical element may be a 1 -dimensional grating. It should be appreciated that the first and second internal optical elements 106a, 106b are not limited to a Fresnel zone plate and a 1- dimensional grating but can be any type of diffractive or refractive internal optical element.

[0081] The picked-off optical beam 156 may be detected by a monitor photodiode (not shown in FIG. 7). It may be advantageous to mount the monitor photodiode on the bottom surface of the transparent carrier 116, so it is situated in the same horizontal plane as the laser 124. This arrangement may be achieved by reflecting the picked-off optical beam 156 off the top surface 117 of the transparent carrier 116 (reflection not shown in FIG. 7). Each transmit channel may have an associated monitor photodiode.

[0082] The internal optical elements depicted in FIGS. 4A, 4B, 5, 6 and 7 may all be considered to be diffractive internal optical elements, since the refractive index has multiple modulation periods across the internal optical element. As described above, in some embodiments the internal optical element may be a refractive optical element. FIGS. 8 A and 8B depict a refractive index profile associated with an exemplary internal refractive optical element. FIG. 8A shows a cross- sectional view of an internal refractive optical element 176 according to an embodiment of the present disclosure. FIG. 8B shows a top view of the internal refractive optical element 176 according to an embodiment of the present disclosure. FIGS. 8A and 8B are similar to FIGS. 4Aand 4B, which depict an internal diffractive optical element, and for brevity a description of common features between the figures will not be repeated. The z-axis may define a center of the internal refractive optical element 176 and the internal refractive optical element 176 may be radially symmetric about the z-axis. A vertical center of the internal refractive optical element 176 may be displaced a height, h, from a bottom surface 121 of the transparent carrier 116. The internal refractive optical element 176 may comprise two types of zones, a first zone 178, and a second zone 180, with each zone having a different, substantially uniform refractive index. The first zone 178 may correspond to unprocessed regions of the transparent carrier 116 and the second zone 180 may correspond to a laser processed region. The refractive index difference between the first zone 178 and second zone may be An. The internal refractive optical element 176 may have a maximum thickness, t, and both its top surface 182 and bottom surface 184 may be curved. The thickness and curvature of first zone 178 and the refractive index difference between the first zone 178 and second zone 180 may be chosen such that a diverging wavefront of an optical beam incident on the internal refractive optical element is collimated by the internal refractive optical element 176. Similarly, a collimated beam incident on the internal refractive optical element 176 may be focused by the internal refractive optical element. As previously disclosed, the internal refractive optical element 176 may be situated within the transparent carrier 116 between the top surface 117 and the bottom surface 121 of the transparent carrier 116.

[0083] FIGS. 8A and 8B depict a refractive optical element 176 formed by having an interface within the transparent carrier 116 between a first zone 178 having a first refractive index and a second zone 180 having a second refractive index different than the first refractive index. The refractive optical element 176 may be a lens. It should be appreciated that a refractive lens can be formed with the transparent carrier by defining a gradient refractive index (GRIN) lens within the transparent carrier. In this embodiment, the refractive lens is formed by a gradient in the refractive index along the y- and x-directions. Thus, rather than having two distinct zones with a different refractive index, a GRIN refractive lens may have a continuously varying refractive index across the lens. A GRIN lens that causes an optical beam passing through it to converge will have a higher refractive index at the center of the lens and a GRIN lens that causes an optical beam passing through it to diverge will have a lower refractive index at the center of the lens.

[0084] It should be appreciated that the stepwise behavior in the refractive index profile depicted in FIG. 5 and the sinusoid behavior depicted in FIG. 6 are only two examples of a refractive index profile that may be used. The internal optical element 106 need not lie in a plane but may curve. More generally, the refractive index profile can vary in a complex manner in all three directions / dimensions, the longitudinal direction, the lateral direction, and the transverse direction, as shown in FIGS. 3A and 3B. As disclosed above, more than one internal optical element may be situated within the transparent carrier or substrate 116. The optical beam 104 (see FIG. 7) may first pass through a first internal optical element 106a and then pass through a second internal optical element 106b. Such complex tailoring of the refractive index profile of one or more internal optical elements 106 may allow shaping a transverse beam profile of the optical beam 104 in any desired manner. For example, it may be advantageous to have a toroidal beam profile as described in more detail below. In some embodiments, a desired refractive index profile may be determined by using artificial intelligence to generate a desired optical intensity profile in the optical beam 104.

[0085] An example of a transverse beam profile that may be generated using a diffractive internal optical element is a transverse beam profile having a toroidal energy distribution. The toroidal energy distribution may have a depressed power level at the center of the optical beam and a radially symmetric higher power level ring surrounding the depressed central area. When this transverse beam profile is launched into a multimode optical fiber, it will primarily excite skew modes in the optical fiber. Advantageously, such a transverse beam profile may propagate down the optical fiber with less modal dispersion than a typical Gaussian power distribution. It should be appreciated that a toroidal beam profile is only one example of an optical beam characteristic that may be achieved with an internal optical element.

[0086] The collimation of the optical beam in the region between the transparent carrier and optical block provides important manufacturing advantages beyond basic optical coupling. When the beam is collimated in this region, the optical coupling becomes significantly more tolerant to lateral misalignment between the transparent carrier and optical block. Even if these components are slightly misaligned laterally, a collimated beam will still focus to substantially the same position on the optical waveguide core for a transmit channel and the photodetector active area fora receive channel, maintaining coupling efficiency between the optical waveguide and E / O component despite possible positional misalignment.

[0087] This tolerance to misalignment occurs because the focal point produced by the refractive lens on the optical block is substantially independent of the lateral position of the collimated beam incident on the lens. While the focal spot position is relatively insensitive to beam position, it remains sensitive to the angle of incidence of the beam on the refractive lens. The individual alignment of each internal optical element helps ensure each optical beam has a perpendicular or substantially perpendicular angle of incidence on its corresponding refractive lens, optimizing coupling efficiency across all channels without requiring perfect lateral alignment between components.

[0088] FIG. 9 shows a cross-sectional view of an optical coupling assembly 110 between an E / O component 125 and an optical waveguide 112 according to an embodiment of the present disclosure. While only a single optical channel is shown in FIG. 9 there may be a plurality of optical channels in the optical coupling assembly 110. The optical coupling assembly 110 places the optical waveguide 112 in optical communication with the active area (not visible in FIG. 9) of the E / O component 125. The optical beam 104 may propagate through an optical block 118 between the active area of the E / O component 125 and an end face 170 of the optical waveguide 112. The optical coupling assembly 110 may include the carrier subassembly 108 as previously described and depicted in FIGS 3A. The carrier subassembly 108 may include a transparent carrier 116, an internal optical element 106, and the E / O component 125 as previously described. Additionally, the optical coupling assembly 110 may include the optical block 118. The optical coupling assembly may also include the optical waveguide 112, which may be an optical fiber. The optical waveguide 112 may be mounted to the optical block 118. The optical block 118 may be mounted to the top surface 117 of the transparent carrier 116. A bottom surface 168 of the optical block 116 may face the top surface 117 of the transparent carrier 116 and may include a refractive lens 158. In a transmit channel, the refractive lens 158 is configured to focus the optical beam 104 into the optical waveguide 112. In a receive optical channel, the refractive lens 158 is configured to collimate the optical beam 104 in a region between the optical block 118 and transparent carrier 116. The refractive lens 158 may be situated adjacent and parallel to the topsurface 1 17 of the transparent carrier 116. Alternatively, the refractive lens 158 may be situated on a side face 166 of the optical block 118 facing the optical waveguide 112. The optical block 118 may also include a reflective surface 114. The reflective surface 114 serves to redirect the optical beam 104. Both the side surface 166 and reflective surface 114 may be flat.

[0089] In some embodiments, the optical beam 104 may be collimated in a region between the internal optical element 106 and the refractive lens 158 in a transmit channel. The optical beam 104 may be considered collimated in a region along its propagation path within a Rayleigh length of a beam waist. An advantage of this arrangement is that optical alignment of the E / O component 125 with the optical waveguide 112 is relatively insensitive to the placement of the optical block 118 on the top surface 117 of the transparent carrier 116. This behavior arises from the position of the focus produced by the refractive lens 158 being substantially independent of the position of the optical beam 104 on the refractive lens 158. While the focal spot position is insensitive to optical beam 104 position, it is sensitive to an angle of incidence of the optical beam 104 on the refractive lens 158. Individual alignment of the internal optical element 106 in each channel of the optical coupling assembly 110 helps to ensure that the optical beam 104 will have a perpendicular or substantially perpendicular angle of incidence on the refractive lens 158.

[0090] For a receive channel, the refractive lens 158 may collimate the optical beam 104 and the internal optical element 106 may focus the optical beam 104 on to the E / O component 125. Optical alignment of the receive channel may be less sensitive than a transmit channel, since the active area of a VCSEL is often smaller than the active area of a photodetector.

[0091] As disclosed above, the optical coupling assembly 110 may include a plurality of optical channels. The optical block 118 may be a monolithic structure that includes a plurality of refractive lens 158 with each optical channel having its associated refractive lens 158. If the optical block 118 is formed by a molding process, a spacing between each refractive lens 158 is fixed. Thus, when the optical block 118 is aligned with the E / O component(s) 125 alignment for each channel cannot be individually optimized. The final alignment will represent a compromise in the optical block 118 alignment which provides the best overall alignment. An advantage of individually defining, or more generally defining, each internal optical element 106 is that alignment of eachinternal optical element can be optimized. As a result, the optical coupling subassembly 108 may be more tolerant of lateral misalignment of the optical block 118.

[0092] A net result of using the internal optical element 106 in both transmit and receive channels is that the optical interconnect module 100 may have a larger tolerance window for placement of the optical block 118 on the transparent carrier 116, which in turn may reduce the manufacturing cost. Also, the optical interconnect module 100 may operate over a wider temperature range, since the transmit and receive optical channels will remain aligned despite dimensional changes caused by varying the operating temperature. In some embodiments, passive alignment of the optical block 118 may be achieved by placing alignment features on the optical block 118 that mechanically engage with mating features on the transparent carrier 116 or some other element of the optical interconnect module 100 (not shown in FIG. 9).

[0093] The optical waveguide 112 may be either a multimode or single mode optical fiber. For multimode fibers, the angular acceptance cone for incoming light is generally larger than for single mode fibers, providing more tolerance for angular misalignment. Single mode fibers require more precise alignment but can support higher bandwidth applications. The individually optimized alignment of each internal optical element 106 can help achieve the tighter alignment tolerances required for efficient coupling into single mode fibers. This capability to achieve precise alignment for single mode fibers represents a significant advantage over conventional approaches that rely on simultaneous alignment of multiple channels.

[0094] Passive alignment may be achieved by using relatively inexpensive, low-precision capital equipment (for example, approximately ± 10 pm tolerance) that places elements to be aligned in contact or proximity to each other and allows mechanical features on the mating elements to register with each other. Passive alignment contrasts with active alignment, which requires expensive, high-precision capital equipment or tooling that enables alignment to approximately ± 1 pm tolerance or better.

[0095] FIG. 9 depicts a specific arrangement of internal optical elements between the E / O component 125 and optical waveguide 112, that is a first optical element 109 within the transparent carrier 116 and a second optical element 159 on the bottom surface 168 of the optical block 118. The first optical element 109 may be an internal optical element 106 as previously described. The second optical element 159 may be considered a surface optical element, since the optical power of the second optical element 159 arises in part from the topology of the surface on which the second optical element 159 is formed. The second optical element may be a refractive lens 158. In FIG. 9 the second optical element 159 is depicted as a refractive lens 158. The first and second optical elements 109 and 159 arrangement depicted in FIG. 9 enables efficient optical coupling between the E / O component 125 and optical waveguide 112. However, in other embodiments the optical elements can be of different types, numbers, and positions in addition to those depicted in FIG. 9. Any surface through which the optical beam 104 propagates may include a surface optical element. These surfaces may include the top surface 117 of the transparent carrier 116 and the bottom surface 168 and side surface 166 of the optical block. Any reflective surface, such as reflective surface 114, may be curved instead of flat to provide optical power. Any transparent material through which the optical beam 104 propagates may have an internal optical element that impacts optical beam propagation. For example, rather than having two optical elements in the optical beam 104 between the E / O component 125 and optical waveguide 112 only a single optical element may be used or more than two, such as three or four, optical elements may be used. Specific examples of these various optical element arrangements are described in more detail below.

[0096] FIG. 10 is a cross-sectional view of a carrier subassembly 108 according to an embodiment of the present disclosure that depicts one of the many possible arrangements. Many of the features of the carrier subassembly 108 are similar to those described above relative to FIG. 3 A and will not be repeated here for brevity. In addition to those features already previously described the carrier subassembly 108 may include a surface optical element 163, such as a refractive lens 120, situated on the top surface 117 of the transparent carrier 116. The refractive lens 120 may be formed by an additive manufacturing process directly on to the top surface 117 of the transparent carrier 116. The additive manufacturing process may be a two-photon polymerization printing process, which is a type of laser processing technique whereby the focused laser inducespolymerization only at the focal point, allowing precise, layer-by-layer building of structures. The refractive lens 120 may be formed of a polymer or glass. A combination of the internal optical element 106 and refractive lens 120 may serve to collimate the optical beam in a region immediately above the refractive lens 120 for a transmit channel and focus the optical beam for a receive channel. Although not shown, in some implementations the refractive lens 120 may be situated on the top surface 117 of the transparent carrier 116 without the use of the internal optical element 106.

[0097] FIG. 11 is a cross-sectional view of a carrier subassembly 108 according to an alternative embodiment of the present disclosure. Many of the features of the carrier subassembly 108 are similar to those described above relative to FIG. 3A and will not be repeated here for brevity. The embodiment shown in FIG. 11 differs from the previously described embodiments in that the transparent carrier 116 includes a plurality of transparent substrates, a first transparent substrate 113a and a second transparent substrate 113b. Unlike previously described embodiments in which the transparent carrier 116 was a monolithic structure, in this embodiment the transparent carrier 116 is a composite structure. Each of first 113a and second 113b transparent substrates may take the form of a rectangular parallelepiped. The first 113a and second 113b transparent substrates may be bonded together to form a unitary structure. The first transparent substrate 113a may form the bottom or first surface of the transparent carrier 116. The second transparent substrate 113b may form the top or second surface of the transparent carrier 116. The first transparent substrate 113a may be arranged to have desirable thermal and mechanical properties suitable for mounting the E / O component 125. It may be said that the first transparent substrate has superior mechanical properties compared to the second transparent substrate. For example, the first transparent substrate may have a lower coefficient of thermal expansion, may have a higher toughness, and may be more rigid than the second transparent substrate. The second transparent substrate 113b may be arranged to have desirable optical properties suitable for defining an internal optical element 106 within the second transparent substrate 113b. In particular, large spatially localized differences in the refractive index of the second transparent substrate 113b may be induced by exposure to laser illumination. For example, the second transparent substrate 113b may be formed from porous silicon dioxide in which the pores are filled with a polymer, photoresist, or other transparent material that undergoes a physical or chemical change when exposed to laserillumination. The second transparent substrate 1 13b may take the form of a thin film having a thickness less than 0.5 mm. In some embodiments, the transparent carrier 116 may be a unitary structure comprising three individual substrates bonded together, with the central substrate having desirable properties for defining an optical element and the other substrates having desirable mechanical properties.

[0098] FIG. 12 is a cross-sectional view of a transmit channel 160 of a carrier subassembly 108 according to an alternative embodiment of the present disclosure. Many of the features of the carrier subassembly 108 are similar to those described above relative to FIG. 3 A and will not be repeated here for brevity. FIG. 12 shows the optical element 109 as an internal optical element 106; however, the optical element 109 may be either an internal optical element, a surface optical element, or there may be a plurality of optical elements within and / or on the transparent carrier 116. The embodiment shown in FIG. 12 differs from the previously described embodiments in that the transparent carrier 116 includes alignment features 164. The alignment features 164 may be located on or immediately adjacent to the top surface 117 of the transparent carrier. The alignment features 164 may be formed during the same manufacturing step as the internal optical element 106. Alternatively, the alignment features 164 may be formed in a bulk manufacturing process, such as but not limited to, photolithography and molding, prior to the mounting of the E / O component 125. The alignment features may be fiducial marks or they may be mechanical features that modify a surface profile of the top surface 117, such as a cleat or depression. Thus, the alignment features 164 may be accurately registered with respect to the optical element 109, for example, within a tolerance of + / - 0.1, 0.2, 0.5, or 1 micron. An advantage of the alignment features 164 being on or near the top surface 117 is that they may be readily detected by a placement tool used to position an optical block 118 (see FIG. 9) onto the top surface 117 of the transparent carrier 116. In some embodiments, the alignment features 164 may mechanically register the optical block 118 to the transparent substrate 116. As previously described, the required placement accuracy of the optical block 118 to the transparent carrier 116 may be much larger, for example, ± 10, 20 or 30 microns, as compared to the required placement accuracy of each individual optical element 109 relative to the active area 134 of each E / O component 125.

[0099] A receive channel of the carrier subassembly 108 may be similarly arranged with a photodetector substituted for the laser 124 and the propagation direction 107 reversed.

[0100] FIG. 13 is a cross-sectional view of a carrier subassembly 108 according to an alternative embodiment of the present disclosure. FIG. 13 is similar to FIG. 12, except that rather than an internal optical element being defined within the transparent carrier 116, a surface optical element 163 is defined on the top surface 117 of the transparent carrier 116. The surface optical element 163 may be a first refractive lens 123. During the same manufacturing step used to define the surface optical element 163 one or more alignment features 164 may be defined on the top surface 117 of the transparent carrier 116. The alignment features may take the form of a raised area with a recess 165. The recess 165 may be configured to mate with a cleat on an optical block (not shown in FIG. 13). An optical block with cleats is described in Patent Cooperation Treaty Publication No. WO2024243512, which is incorporated by reference as if set forth in its entirety herein. Using the same processing tool in the same manufacturing step to define both the surface optical element 163 and the alignment features 164 helps ensure accurate registration between these features. In this embodiment, there is no internal optical element; however, in an alternative embodiment an internal optical element can also be present and work in cooperation with the first refractive lens 120 to control the optical beam 104. While FIGS. 10 and 13 illustrate a surface optical element (163, 120, 123) defined on the second major surface 1 17, it is contemplated that in alternative configurations, potentially not using flip-chip mounting facing the carrier, a surface optical element could potentially be situated on the first major surface 121 if space and mounting methods permit.

[0101] FIG. 14 is a method 200 of making a carrier subassembly according to an embodiment of the present disclosure. At a first step 202, an E / O component may be mounted to a first or bottom major surface of a transparent carrier. In some embodiments, the E / O component may have a plurality of active areas. In some embodiments, a plurality of E / O components may be mounted to the first major surface in step 202. Flip-chip mounting may be used to mount the E / O components providing both an electrical and mechanical connection between the transparent carrier and the E / O components. The E / O component(s) may be oriented so that all active areas of the E / O component(s) face the first major surface of the transparent carrier. As described above,each active area may have a contact ring that surrounds or substantially surrounds each active area of the E / O component as described above. In step 204, a processing / placement head of a processing tool may accurately align with an active area on the E / O component. The processing tool may remove material from, add material to, or modify the physical properties of the transparent carrier at desired locations within or on the surface of the transparent carrier. The processing tool may be a laser processing tool, an additive manufacturing processing tool, or some other type of processing tool capable of defining an optical element. Alignment may be achieved by either adjusting a position of a processing head, adjusting a position of the transparent carrier, adjusting a position of an intervening element in the processing tool situated between the transparent carrier and the processing head or some combination of these adjustments. In step 206, the processing tool may write or define an optical element within or on the first major surface the transparent carrier that is accurately aligned with the active area of the E / O component. The optical element can be a surface optical element or an internal optical element. The processing tool may define a plurality of optical elements that are serially arranged in a single optical channel. As disclosed above, an E / O component may have a plurality of active areas and a corresponding optical element(s) may be written for each active area. Importantly, each optical element is aligned individually with each active area, so no compromise in alignment is required as may be the case if a plurality of active areas are simultaneously aligned with a plurality of optical elements. If there are a plurality of E / O components each active area of each E / O component may have a corresponding optical element(s) written in turn. As such each individually defined optical element's position is customized based on the position of its corresponding active area independent of the positions of other individually defined optical elements. In step 208, a decision is made whether an optical element(s) has been written for all active areas on all electrooptic components that are mounted to the first major surface of the transparent carrier. If not, the method returns to step 204 where the processing head is aligned with another active area and the defining step 206 is repeated. If the decision in step 208 is a yes, indicating that all active areas have had corresponding optical elements written, the method 200 proceeds to step 210 which may represent a completed carrier subassembly. The carrier subassembly may then be integrated into an optical coupling assembly and further integrated into an optical interconnect module as described above.

[0102] It may be said that in an embodiment of the present disclosure a method is described for assembling a carrier subassembly. In a first step an electrooptic component having a plurality of active areas is mounted on a first major surface of a transparent carrier. Each of the plurality of active areas which is configured to emit or detect an optical beam that propagates through the transparent carrier. In a second step, a processing head of a processing tool is aligned with a first active area of the plurality of active areas. A first optical element is then written within or on the transparent carrier such that the first optical element is in optical alignment with the first active area of the electrooptic component. The aligning and defining steps are then repeated for each active area of the plurality of active areas.

[0103] One feature of method 200 is that an optical element is aligned with each active area individually. Thus, each active area may be said to have a corresponding optical element which is individually aligned with its corresponding active area. The defining of the optical elements may occur in a sequential manner, with a first optical element written corresponding to a first active area, a second optical element written corresponding to a second active area, and so on, until each active area has a corresponding optical element. It should be appreciated that multiple processing heads may be used to fabricate a single carrier subassembly. In this case, a plurality of optical elements may be written simultaneously, but each optical element will be aligned with its corresponding active area.

[0104] An advantage of the method 200 is that an optical element may be aligned to each active area individually. This contrasts with many prior art systems that have multiple active areas on a single die in which a single optic having multiple refractive lenses is aligned with all active areas simultaneously. This inevitably results in a compromise in alignment of any individual active area to its corresponding refractive lens. By individually aligning the optical element to each active area, higher coupling efficiency between the E / O component and the optical waveguide may be achieved for all active areas on the E / O component. During the alignment process the E / O component may be energized so that optical alignment between an individually defined optical element and an active area can be achieved without reference to a contact ring or any other marking on the E / O component. Alternatively, the E / O component may not be energized and opticalalignment between an optical element and an active area may be achieved by aligning to the inactivated active area, contact ring or some fiducial mark on the E / O component.

[0105] FIG. 15 is a perspective view of a plurality of carrier subassemblies 222 cojoined in a wafer 220 prior to singulation subassembly according to an embodiment of the present disclosure. The plurality of the carrier subassemblies 222 may be fabricated on a single planar wafer 220. The wafer 220 is transparent at the operating wavelength(s) of the optical interconnect module into which the individual carrier subassembly 222 is incorporated. Individual carrier subassemblies 222 may be formed by mounting E / O components (not clearly visible in FIG. 15) to a bottom surface of the wafer 220 and then individually defining an optical element 224 associated with the active areas of the E / O components as described above. Individual carrier subassemblies 222 may then be singulated from the wafer 220. In embodiments where the optical elements 224 are individually defined using a processing tool after component mounting but prior to singulation, these alignment features 226 can be defined at each carrier subassembly site using the same processing tool and potentially during the same processing step (or while maintaining alignment from the element definition step), ensuring accurate registration between the optical element 224 and the alignment feature 226 on the wafer level, consistent with the principles previously described.

[0106] The E / O component has generally been described as either a VCSEL having multiple individual emitters or a photodetector having multiple individual detectors; however, the E / O component is not so limited. In particular, the E / O component may be a photonic integrated circuit, such as, but not limited to, a silicon photonics integrated circuit. The driver and TIA may be integrated into the photonics integrated circuit, or the driver and TIA may be separate components. In some embodiments, the driver and TIA may be combined into a separate component which is placed in electrical communication with the photonic integrated circuit. The photonic integrated circuit may include a plurality of individual emitters and a plurality of individual detectors. In some embodiments, the photonic integrated circuit may only include emitters and the photodetectors may be on a separate component.

[0107] The above description is generally directed to mounting an E / O component prior to defining an optical element, but the invention is not so limited. In an alternative embodiment, a plurality of optical elements may be written either within or on a first or opposed second major surface of a transparent carrier. A placement head of a die bonding tool may then be aligned with the plurality of optical elements. An electrooptic component having a plurality of active areas may be mounted on the first major surface of the transparent carrier with the placement head. Each active area of the plurality of active areas is configured to emit or detect a corresponding optical beam that propagates through the transparent carrier and each of the plurality of active areas is in optical alignment with each of the plurality of optical elements.

[0108] The previous description has been chiefly directed towards defining an optical element within or on a surface of a transparent carrier that supports an E / O component to define a carrier subassembly; however, the present invention is not so limited. As noted above, an optical element can also be defined within or on a surface of the optical block. Embodiments of the current invention that define an optical element on the optical block will now be described.

[0109] FIG. 16 depicts a cross-sectional view of an optical block subassembly 198. The optical block subassembly 198 includes an optical block 118 having a permanently attached, i.e. pigtailed, optical waveguide 112. An optical axis 105 extends through the optical block 118. The optical axis 105 traverses two surfaces, a bottom surface 168 and a side surface 166. Additionally, the optical axis 105 may have its orientation changed by intersecting a reflective surface 114. An optical element may be defined in any of five different regions within or on a surface of the optical block 118. A surface optical element 186 may be defined on the side surface 166 of the optical block 118. A surface optical element 188 may be defined on the bottom surface 168 of the optical block 118. The surface optical elements 186, 188 may be diffractive or refractive optical elements. A surface optical element 190 may also be formed on the reflective surface 114. The surface optical element 190 may be a diffractive or reflective optical element. An internal optical element 192 may be formed along the optical axis 105 in a region between the bottom surface 168 and the reflective surface 114. The internal optical element 192 may be a diffractive or refractive optical element. An internal optical element 194 may be formed along the optical axis 105 in a regionbetween the side surface 166 and the reflective surface 114. The internal optical element 194 may be a diffractive or refractive optical element.

[0110] The optical block 118 may include a waveguide support portion 196 arranged to support an optical waveguide 112, such as an optical fiber. The waveguide support portion 196 may support a plurality of optical waveguides 112 arranged in a row along the lateral direction (not visible in FIG. 16, see FIG. 1). The optical waveguides 112 may be mechanically connected to each other and mounted on the waveguide support portion 196 in a single processing step. Each optical waveguide 112 may have an optical waveguide core. Each optical waveguide core may transmit optical signals along its length as part of an optical channel. The optical waveguide cores may be spaced at a regular pitch, such as 250 microns between adjacent waveguide cores. In an embodiment, the optical waveguides 112 may be mounted to the waveguide support portion 196 of the optical block 118 prior to definition of an optical element 186, 188, 190, 192, 194 within or on a surface of the optical block 118. Each optical element 186, 188, 190, 192, 194 may be individually defined with respect to an associated optical waveguide core mounted on the optical block 118. Thus, each optical channel traversing the optical block 118 can be individually aligned and optimized. Advantageously, individual alignment of the optical element 186, 188, 190, 192, 194 with the optical waveguide core will relax manufacturing tolerances associated with mounting the optical waveguide 1 12 and allow use of optical waveguides having more variation in the core location. In particular, individual alignment of each optical channel through the optical block 118 may enable use of single mode optical fiber as the optical waveguide 112. Efficient optical coupling into single mode optical fiber has significantly tighter alignment tolerances than multimode fiber, which has been used in many prior art optical interconnect modules

[0111] The optical block 118 may have one or more alignment marks or features 199. The alignment marks or features 199 may be fabricated by a bulk manufacturing process or may be individually defined based at least in part on the location of the optical waveguides 112. The alignment marks or features 199 may be on the bottom surface of the optical block 118 (see FIG. 16). An example of such alignment features is described in Patent Cooperation Treaty Application No. PCT / US2024 / 030998 having the same assignee as the present disclosure, which is incorporated herein by reference in its entirety. The alignment marks or features 199 are arrangedto assist in registration of the optical block subassembly 198 to the carrier subassembly 108. For example, the alignment features or marks 199 on the optical block 118 depicted in FIG. 16 may be arranged to align with the alignment features 164 on the transparent carrier 116 depicted in FIGS. 12 and 13. Depending on the nature of the alignment features 164 and 199, the alignment features may register directly with each other (i.e. physically contact) or the alignment features 164 and 199 may indirectly register with each other, such as through an optical block guide 230 (see FIG.17). The registration may be an active registration using optical alignment of the alignment features or marks 199 with the alignment features 164, or a mechanical interference between the alignment features or marks 199 and the alignment features 164 that passively registers the optical block subassembly 198 to the carrier subassembly 108. The placement of the optical element 186, 188, 190, 192, 194 within or on a surface of the optical block 118, may be determined at least in part by the location of the alignment features or marks 199 in addition to the location of each of the optical waveguides 112. In some embodiments, the alignment features or marks 199 may be made using the same processing tool used to define the optical element 186, 188, 190, 192, 194 within or on a surface of the optical block 118.

[0112] In another embodiment, rather than the optical block 118 having a pigtailed optical waveguide 112, the side surface 166 may be arranged to mate with a detachable optical waveguide, such as a plurality of optical fibers mounted in an optical ferrule. The optical ferrule may be a MT ferrule, but other types of optical ferrules may be used. The optical fibers may be arranged in a row extended in the lateral direction. There may be a single row of optical fibers or a plurality of rows of optical fibers. The side surface 166 may have one or more alignment features (not shown in FIG. 16) arranged to mate with corresponding alignment features on the detachable optical waveguide. An example of such alignment features is described in Patent Cooperation Treaty Application No. PCT / US2024 / 030998 having the same assignee as the present disclosure, which is incorporated herein by reference in its entirety.

[0113] In other words, an optical block subassembly may be comprised of an optical block having a bottom surface and a side surface configured to transmit an optical beam and an alignment feature on the side surface configured to mate with an attachable / detachable optical fiber cable. The optical block includes a plurality of optical elements and each of the plurality of opticalelements is configured to be associated with a corresponding optical waveguide of the attachable / detachable optical fiber cable and a location of each of the plurality of optical elements is individually defined at least in part by a position of the alignment features.[00114J It should be appreciated that the optical block 118 may have a plurality of optical elements in any given optical channel. Some of the optical elements may be predefined by some bulk manufacturing process, such as molding, and some optical elements may be defined individually to optimize optical coupling into and out of the optical waveguide 112.

[0115] The reflective surface on the optical block may be formed through various methods. In some embodiments, the reflective surface may be a simple flat mirror. In other embodiments, the reflective surface may incorporate curved regions to provide additional optical power. The curved regions may be formed during initial manufacturing of the optical block or may be individually defined for each channel using additive manufacturing or other processing techniques. When individually defined, each curved region can be optimized for its specific channel, taking into account the position of both the optical waveguide core.

[0116] FIG. 17 illustrates an optical coupling assembly 240 including an optical block guide 230 according to an embodiment of the present disclosure. The optical coupling assembly 240 may be comprised of an optical block subassembly 198, similar to that previously shown in FIG. 16, and a carrier subassembly 108, similar to that previously shown in FIG. 13. The optical block subassembly 198 may have a surface optical element 188 on the bottom surface of the optical block 118. Also, on the bottom surface of the optical block 188 may be alignment features 199. An encapsulant 236 may fill a region between the optical waveguide 112 and the side surface of the optical block 118. Both the surface optical element 188 and alignment features 199 may be individually defined based on a position of the waveguide 112. In some alternative embodiments, both these elements may be made in a bulk manufacturing process or the alignment features 199 may be made using a bulk manufacturing process and the surface optical element 188 may be individually defined. The carrier subassembly 108 may have an E / O component 125 which emits or receives an optical beam 104. The carrier subassembly 108 may have a surface optical element 163 on a top surface of the transparent substrate 116. Also, on the top surface of the transparentsubstrate 116 may be alignment features 164. Both the surface optical element 163 and alignment features 164 may be individually defined based on a position of an active area (not visible in FIG. 17) of the E / O component 125. In some alternative embodiments, both these elements may be made in a bulk manufacturing process, or the alignment features 164 may be made using a bulk manufacturing process and the surface optical element 163 may be individually defined.

[0117] The optical block guide 230 may be formed from a transparent material, such as, but not limited to, glass. The optical block guide 230 may have top alignment features 232 formed in its top surface and bottom alignment features 234 formed in its bottom surface. The top alignment features 232 are configured to mate with alignment features 199 of the optical block subassembly 198 and the bottom alignment features are configured to mate with the alignment features 164 of the carrier subassembly. The top and bottom alignment features 232 and 234 may be a slot in the optical block guide 230. Although not shown in FIG. 17, in some embodiments the top and bottom alignment features 232 and 234 may comprise a single feature, such as a through slot, that extends from the top to the bottom surface of the optical block guide 230. The top and bottom alignment features 232 and 234 may be made using a laser selective etching process in which regions of the optical block guide 230 are selectively irradiated and subsequently etched to remove material from the irradiated region.

[0118] An advantage of using the optical block guide 230 between the optical block subassembly 198 and the carrier subassembly 108 is that the optical block alignment features 199 and the carrier subassembly alignment features 164 may both protrude from the surround surface. As such, both the optical block alignment features 199 and the carrier subassembly alignment features 164 may be additively manufactured. In alternative embodiments, one or both the optical block alignment features 199 and the carrier subassembly alignment features 164 may be fabricated using a bulk manufacturing process.

[0119] FIG. 18 illustrates an exemplary method 400 of assembling an optical block subassembly according to an embodiment of the present disclosure. In a first step 402 a plurality of bulk features may be fabricated into an optical block by a bulk manufacturing process, such as but not limited to molding or photolithography. The plurality of bulk features may include arefractive lens on either a bottom or side surface or a curved mirror on a reflective surface of the optical block. The plurality of features may include a plurality of alignment grooves or holes which support and register a plurality of optical waveguides. The plurality of bulk features may further include alignment marks and features that assist in alignment of the optical block to an optical engine. In a second step 404, a plurality of optical waveguides may be permanently affixed to a waveguide mounting portion of the optical block. The plurality of optical waveguides may be part of a ribbon cable and may be affixed to the optical block simultaneously in a single processing step. The optical block may have a plurality of alignment features that help to accurately register the position of the optical waveguides relative to other features on the optical block. The plurality of alignment features may be a regularly spaced pattern of grooves, which help align each optical waveguide. The plurality of optical waveguides may be a plurality of optical fibers. The plurality of optical fibers may be dispersed in a row having a common pitch between adjacent optical fibers. In a third step 406, a processing head is aligned based on a position of the optical waveguide 112. The alignment of the processing head may also be based at least in part on the location of the alignment marks or features 199 (see FIG. 16). In a fourth step 408, an optical element may be defined within or on a surface of the optical block. A location of the optical element may be based, at least in part, on a position of the optical waveguide 112 and optionally the alignment marks and features 199. In some embodiments, the location of the optical element may be based on a position of a core of the optical waveguide. In some embodiments, the optical element may be a plurality of optical elements serially arranged within or on a surface of the optical block. The location of the optical element may be chosen to optimize optical coupling into and / or out of the optical waveguide. The optical element may be an additively manufactured feature on the side surface 166, bottom surface 168 or reflective surface 114. Alternatively, the optical element may be defined within the bulk of the optical block by a spatially localized changed in the refractive index, for instance, by scanning a focal spot of a processing optical beam emitted by a laser processing tool, similar to the process described for defining internal elements in the transparent carrier. It should be noted that some laser processing techniques, particularly those that use two-photon polymerization as mentioned above, serve as both laser processing and additive manufacturing methods simultaneously, as they selectively build up material using focused laser energy. In a fifth step 410, a decision is made whether an optical element(s) has been written for all optical waveguides that are affixed to the optical block. If not, the method returns to step 406 where theprocessing head is aligned with another optical waveguide and the defining step 408 is repeated. If the decision in step 410 is a yes, indicating that all optical waveguides have had corresponding optical elements defined, the method 400 proceeds to step 412 which may represent a completed optical block subassembly. The optical block subassembly may then be integrated with a carrier subassembly and further integrated into an optical interconnect module as described above.

[0120] A plurality of optical blocks may be fabricated on a single planar wafer. Individual optical blocks may be singulated from the wafer. The optical waveguides may be affixed to the optical blocks either before or after singulation. In an embodiment, the optical waveguides may be a ribbon optical fiber cable and a plurality of ribbon optical fiber cables may be affixed to a row of cojoined optical blocks prior to the singulation step. Since the optical waveguides are permanently affixed to the optical block after this step, defining of the optical elements may occur while the optical blocks remain cojoined.

[0121] The manufacturing process may proceed in different sequences depending on the specific implementation requirements. In one approach, the electrooptic components are mounted first, followed by writing of the optical elements in the transparent carrier. In another approach, the optical elements are written first, and then the electrooptic components are precisely mounted in alignment with the pre-written optical elements. Similarly, for the optical block, the optical waveguides may be mounted before or after defining optical elements in or on the optical block. The sequence choice may depend on various factors including the specific materials used, the type of optical elements being formed, and the available manufacturing equipment. In all cases, the ability to individually optimize each optical channel provides flexibility in the manufacturing process while maintaining high coupling efficiency.

[0122] FIG. 19 shows an exemplary optical block subassembly 198 that may result from application of the assembly method 400 depicted in FIG. 18. A plurality of optical waveguides 112 are affixed to an optical block 118. The plurality of optical waveguides 112 may be part of an optical fiber cable 102. In this example, there are twelve optical waveguides 112 in the optical fiber cable 102, which is a ribbon cable. Each optical waveguide 112 has an associated curved mirror 191 on the reflective surface 114. Each curved mirror 191 may be defined after itsassociated optical waveguide 112 has been affixed to the optical block 118. The location and curvature of the curved mirror 191 may be individually optimized to facilitate efficient optical coupling into or out of each of the optical waveguides 112.[00123J In yet another embodiment, an optical block subassembly 198 may be mated with a carrier subassembly 108 prior to definition of an optical element that will enable efficient optical coupling between the E / O components 125 in the carrier subassembly 108 and the optical waveguides 112 in the optical block subassembly 198. The optical element can be defined anywhere along the optical path between the E / O components 125 and the optical waveguides 112. In particular, the optical element may be a curved mirror 191 defined on the reflective surface 114 of the optical block 118.

[0124] While FIGS. 16 and 19 have depicted the optical block 118 as a monolithic structure, an alternative embodiment, the optical block 118 may be a unitary structure composed of different materials permanently bonded to each other. The materials may be selected based on their material properties. In a manner analogous to that depicted in FIG. 11, the optical block 118 may be a unitary structure comprising individual elements bonded together, with at least one individual element having desirable properties for defining an optical element and the other individual elements having desirable mechanical properties. FIGS. 20 and 21 show different embodiments of such a composite optical block subassembly 193. The composite optical block subassembly 193 includes a composite optical block 197 formed from bonding together two transparent elements. A first transparent element 185 having desirable mechanical properties and a second transparent element 195 having desirable properties for defining an optical element. The second transparent element 195 may take the form of a rectangular parallel opiped as shown in FIG. 20. Two optical elements may be defined within the second transparent element 195, a first optical element may be a beam steering diffractive optical element 175 that serves to redirect the optical axis 105 in a manner similar to that of reflective surface shown in FIG. 16. The second optical element 177 may be formed along the optical axis 105 in a region between the side surface 166 and the beam steering diffractive optical element 175. The second optical element 177 may be a diffractive or refractive optical element configured to collimate an optical beam exiting theoptical waveguide 1 12 (Rx channel) or focusing an optical beam into the optical waveguide 1 12 (Tx channel).

[0125] FIG. 21 shows a different embodiment of a composite optical block 197. In this embodiment, there are three different elements bonded together to form the composite optical block 197. A first transparent element 185 having desirable mechanical properties, a second transparent element 195 having desirable properties for defining an optical element and a third transparent element 174. The third transparent element 174 includes the reflective surface 114 and redirects the optical axis 105. The third transparent element 174 may have a simple triangular cross-sectional shape as shown in FIG. 21, making this element easy to fabricate. The second transparent element 195 may again take the form of a rectangular parallelepiped; however, unlike the second transparent element 195 depicted in FIG. 20, the second transparent element 195 in FIG. 21 has only the second optical element 177 defined within it.

[0126] While FIGS. 20 and 21 depict two specific arrangements of a composite optical block 197, it should be appreciated that a composite optical block can be composed of different shapes and arrangements of transparent elements other than those depicted in FIGS. 20 and 21. In this disclosure the term optical block may refer to both a monolithic optical block formed from a single material or a composite optical block formed from a plurality of elements.

[0127] Some embodiments in this disclosure have described having only the optical block and the transparent substrate in the optical path between the E / O element and the optical waveguide; however, in the embodiment depicted in FIG. 17 an optical block guide may be positioned between the transparent substrate and the optical block. In addition to the alignment features depicted in FIG. 17, the optical block guide may have either a bulk manufactured optical element, such as a refractive lens, or an individually defined optical element. An example of such an optical block guide, denoted as a lens substrate, is described in United States patent No. 9,151,916, which is incorporated herein by reference in its entirety. The lens substrate optical element may be aligned with the E / O element either through passive or active alignment.

[0128] In summary, the invention disclosed herein describes a system and method that establishes an optical path by defining an optical element along that path that changes the wavefront curvature of an optical beam propagating along the optical path. The invention may be applied to an optical interconnect module having a plurality of transmit and / or receive channels. The optical path in each channel is individually defined for that channel so that an E / O component and optical waveguide are optically aligned and can efficiently propagate an optical signal between them. The optical element may be defined on a surface that intersects the optical path or within a transparent material through which the optical path propagates. Specifically, the optical element may be defined on or in a transparent carrier and / or optical block. The transparent carrier and optical block may each be formed as either monolithic or composite structures. For composite structures, different materials may be selected based on their specific properties. For example, one material may be chosen for superior mechanical properties such as thermal stability and structural rigidity, while another material may be optimized for optical properties such as the ability to form internal optical elements through laser processing. In one embodiment, a material comprising a silica scaffolding with polymer-filled voids may be used for regions where optical elements are to be written, as this structure allows significant localized changes in refractive index through laser processing. In another embodiment, the optical element may be defined through an additive manufacturing process. Alignment features may be defined during the same process step that defines the optical element. The E / O components and associated electronics, such as a laser driver and TIA, may use flip-chip electrical connections. In some embodiments, some of the components may use wirebond electrical connections and some may use a flip-chip electrical connection. It is further noted that a single optical channel within the module may utilize individually defined optical elements located in multiple positions along the optical path, for example, incorporating a first individually defined element within or on the transparent carrier 116 (e.g., element 106 or 163) and a second individually defined element within or on the optical block 118 (e.g., element 186, 188, 191, 192, or 194), where both elements are defined based on the position of the associated electrooptic component active area or optical waveguide core to improve or optimize coupling.

[0129] It should be noted that the illustrations and discussions of the embodiments and examples shown in the figures are for exemplary purposes only and should not be construed limiting the disclosure. One skilled in the art will appreciate that the present disclosurecontemplates a range of possible modifications of the various aspects, embodiments and examples described herein. For example, some fiducial mark other than a contact ring may be used to align an optical element with an active area of an E / O component. Not all optical channels in an optical interconnect module may need to have an individually defined optical element. In particular, the transmit channels may have an individually defined optical element, but no individually defined optical element may be present in a receive channel.

[0130] While the foregoing description primarily discusses arrangements where the optical signal path involves emission from or reception at the active face (e.g., surface 130) of the electrooptic component 125, such as the face mounted towards the transparent carrier 116 in typical flip-chip configurations where light passes directly into the transparent carrier 116, the teachings of the present disclosure are not limited to such configurations. In alternative embodiments, the electrooptic component 125 itself may be configured for optical signal transmission through its own substrate material (e.g., the GaAs, InP, or Si substrate upon which the active area 134 is formed). For instance, a VCSEL 124 may be constructed as a "back-emitting" VCSEL, wherein the primary optical output exits through the VCSEL's substrate rather than its top active face. Similarly, a photodetector 126 may be constructed as a "back-receiving" photodetector, where the incident optical signal enters through the photodetector's substrate to reach the active area 134. In such arrangements, the substrate material of the electrooptic component 125 is substantially transparent at the operating wavelength of the optical signal to permit efficient transmission therethrough. In these back-emitting or back-receiving embodiments, the individually defined optical elements described herein (e.g., internal optical elements 106, surface optical elements 163, 186, 188, 190, 191, or others) situated within or on the transparent carrier 116 or the optical block 118 can still be employed and individually aligned relative to the active area 134 to facilitate efficient optical coupling between the electrooptic component 125 and the optical waveguide 112, albeit with the light path entering or exiting the electrooptic component 125 via its substrate. The alignment and definition processes (e.g., method 200, 400) can be adapted accordingly to align the optical elements (e.g., 106, 163, 188, 191) with the optical signal path passing through the electrooptic component's substrate.

[0131] It should be understood that the concepts described above with the above-described embodiments and examples may be employed alone or in combination with any of the other embodiments and examples described above. It should further be appreciated that the various alternatives described above with respect to one illustrated embodiment can apply to all other embodiments and examples described herein, unless otherwise indicated. Reference is therefore made to the claims.

Claims

CLAIMS1. A carrier subassembly comprising: a transparent carrier having a first major surface and an opposed second major surface; an electrooptic component having an active area, wherein the electrooptic component is mounted to the first major surface; and an internal optical element situated within the transparent carrier between the first and second major surfaces, wherein the internal optical element is optically aligned with the active area of the electrooptic component.

2. The carrier subassembly of claim 1, wherein the internal optical element has a spatially varying index of refraction.

3. The carrier subassembly of any one of claims 1-2, wherein the internal optical element is an internal diffractive optical element.

4. The carrier subassembly of any one of claims 1-2, wherein the internal optical element is an internal refractive optical element.

5. The carrier subassembly of any one of claims 1-2, wherein the internal optical element is combination of an internal refractive optical element and an internal diffractive optical element.

6. The carrier subassembly of any one of claims 1-5, wherein the internal optical element is in a transmit channel and is configured to reduce the divergence of an optical beam emitted by the active area of the electrooptic component.

7. The carrier subassembly of claim 6, wherein the internal optical element is configured to collimate the optical beam.

8. The carrier subassembly of any one of claims 6-7, wherein the internal optical element is configured to orient an optical axis of the optical beam perpendicular to the second major surface within a manufacturing tolerance.

9. The carrier subassembly of any one of claims 1-5, wherein the internal optical element is in a receive channel and is configured to focus an optical beam incident on the second major surface of the transparent carrier on to the active area of the electrooptic component.

10. The carrier subassembly of any one of claims 1-3 and 5-9, wherein the internal optical element comprises a Fresnel zone plate.

11. The carrier subassembly of any one of claims 1-3 and 6-10, wherein the internal optical element comprises a plurality of internal optical elements arranged in series.

12. The carrier subassembly of any one of claims 1-11, further comprising a refractive lens on the second major surface.

13. The carrier subassembly of any one of claims 1-12, wherein the internal optical element is configured to pick-off a portion of an optical beam transmitted through the internal optical element.

14. The carrier subassembly of any one of claims 1-12, wherein the electrooptic component is a plurality of electrooptic components.

15. The carrier subassembly of claim 14, wherein the plurality of electrooptic components comprises two lasers and two photodetector die.

16. The carrier subassembly of claim 14, wherein the plurality of electrooptic components comprises a photonic integrated circuit and a photodetector die.

17. The carrier subassembly of claim 14, wherein each electrooptic component of the plurality of electrooptic components has a corresponding internal optical element that is individually aligned with that electrooptic component independent of the alignment of other internal optical elements.

18. The carrier subassembly of any one of claims 1-13, wherein the electrooptic component is a single photonic integrated circuit.

19. The carrier subassembly of any one of claims 1-18, wherein a refractive index profile of the internal optical element varies in three dimensions.

20. The carrier subassembly of any one of claims 1-19, wherein a refractive index profile of the internal optical element is determined using artificial intelligence.

21. The carrier subassembly of any one of claims 1-20, wherein the transparent carrier comprises a plurality of transparent substrates bonded together to form a unitary structure.

22. The carrier subassembly of claim 21, wherein the plurality of transparent substrates comprises a first transparent substrate and a second transparent substrate, the first transparent substrate forms the first major surface and the second transparent substrate forms the second major surface.

23. The carrier subassembly of claim 22, wherein the internal optical element is located within the second transparent substrate.

24. The carrier subassembly of any one of claims 22-23, wherein the first transparent substrate has superior mechanical properties compared to the second transparent substrate.

25. The carrier subassembly of any one of claims 1-24, wherein an alignment mark is situated on or directly beneath the second major surface.

26. The carrier subassembly of claim 25, wherein the alignment mark is written during the same processing step as the internal optical element.

27. An optical coupling assembly comprising: a transparent carrier having a first major surface and an opposed second major surface; an electrooptic component having an active area mounted to the first major surface and configured to emit an optical beam through the transparent carrier or detect an optical beam transmitted through the transparent carrier; an internal optical element situated within the transparent carrier between the first and second major surfaces, wherein the internal optical element is optically aligned with the active area of the electrooptic component; an optical block mounted on the second major surface; and an optical waveguide in optical communication with the active area.

28. The optical coupling assembly of claim 27, wherein the optical beam propagates through the optical block between the active area and the optical waveguide.

29. The optical coupling assembly of any one of claims 27-28, wherein the optical waveguide is mounted to the optical block.

30. The optical coupling assembly of any one of claims 27-29, further comprising a refractive lens situated on a face of the optical block.

31. The optical coupling assembly of any one of claims 27-30, wherein the optical waveguide is an optical fiber.

32. The optical coupling assembly of any one of claims 27-31, wherein the optical beam is collimated between the first major surface and the optical block.

33. The optical coupling assembly of any one of claims 27-32, further comprising a reflective surface situated on a face of the optical block.

34. The optical coupling assembly of any one of claims 27-33, wherein the internal optical element picks-off a portion of the optical beam transmitted through the internal optical element.

35. The optical coupling assembly of any one of claims 27-34, further comprising a plurality of alignment marks situated on or directly beneath the second major surface that aid in positioning the optical block on the transparent carrier.

36. The optical coupling assembly of any one of claims 27-35, wherein the internal optical element is an internal diffractive optical element.

37. The optical coupling assembly of any one of claims 27-35, wherein the internal optical element is an internal refractive optical element.

38. The optical coupling assembly of any one of claims 27-35, wherein the internal optical element is a combination of an internal diffractive optical element and an internal refractive optical element.

39. The optical coupling assembly of any one of claims 27-38, wherein the transparent carrier comprises a plurality of transparent substrates bonded together to form a unitary structure.

40. The optical coupling assembly of claim 39, wherein the plurality of transparent substrates comprises a first transparent substrate and a second transparent substrate, the first transparent substrate forms the first major surface and the second transparent substrate forms the second major surface.

41. The optical coupling assembly of claim 40, wherein the internal optical element is located within the second transparent substrate.

42. The optical coupling assembly of any one of claims 40-41, wherein the first transparent substrate has superior mechanical properties compared to the second transparent substrate.

43. The optical coupling assembly of any one of claims 27-42, wherein an alignment mark is situated on or directly beneath the second major surface and helps to position the optical block on the second major surface.

44. The optical coupling assembly of claim 43, wherein the alignment mark is written during the same processing step as the internal optical element.

45. An optical interconnect module comprising: a transparent carrier having a first major surface and an opposed second major surface; and an internal optical element situated within the transparent carrier between the first and second major surfaces.

46. The optical interconnect module of claim 45, further comprising an electrooptic component mounted to the first major surface and arranged to emit an optical beam through the transparent carrier or detect an optical beam transmitted through the transparent carrier.

47. The optical interconnect module of any one of claims 45-46, wherein the internal optical element comprises two internal optical elements arranged in series.

48. The optical interconnect module of any one of claims 45-47, further comprising a refractive lens formed on the second major surface of the transparent carrier.

49. The optical interconnect module of any one of claims 45-48, wherein the internal optical element picks-off a portion of an optical beam transmitted through the internal optical element.

50. The optical interconnect module of claim 49, wherein the picked-off portion of the optical beam is sampled by a monitor photodiode.

51. The optical interconnect module as recited in any one of claims 45-50, wherein the optical interconnect module has a plurality of transmit channels.

52. The optical interconnect module of claim 50, wherein each transmit channel of the plurality of transmit channels includes an internal optical element that is individually aligned with its corresponding electrooptic component independent of the alignment of internal optical elements in other transmit channels.

53. The optical interconnect module of any one of claims 45-51, wherein the optical interconnect module has a plurality of receive channels.

54. The optical interconnect module of claim 51, wherein each receive channel of the plurality of receive channels includes an internal optical element that is individually aligned with its corresponding electrooptic component independent of the alignment of internal optical elements in other receive channels.

55. The optical interconnect module of any one of claims 46-54, wherein the electrooptic component is a plurality of electrooptic components.

56. The optical interconnect module of claim 55, wherein the plurality of electrooptic components comprises two laser die and two photodetector die.

57. The optical interconnect module of claim 56, wherein the plurality of electrooptic components comprises a photonic integrated circuit and a photodetector die.

58. The optical interconnect module of any one of claims 45-54, wherein the electrooptic component is a single photonic integrated circuit.

59. The optical interconnect module of any one of claims 45-58, wherein a refractive index profile of the internal optical element is determined using artificial intelligence.

60. The optical interconnect module of any one of claims 45-59, wherein the optical element is an internal diffractive optical element.

61. The optical interconnect module of claim 60, wherein the internal diffractive optical element comprises a Fresnel zone plate.

62. The optical interconnect module of any one of claims 45-61, wherein the optical element is an internal refractive optical element.

63. The optical interconnect module of any one of claims 45-60, wherein the optical element is a combination of an internal diffractive optical element and an internal refractive optical element.

64. The optical interconnect module of any one of claims 45-63, wherein the transparent carrier comprises a plurality of transparent substrates bonded together to form a unitary structure.

65. The optical interconnect module of claim 64, wherein the plurality of transparent substrates comprises a first transparent substrate and a second transparent substrate, the first transparent substrate forms the first major surface and the second transparent substrate forms the second major surface.

66. The optical interconnect module of claim 65, wherein the internal optical element is located within the second transparent substrate.

67. The optical interconnect module of any one of claims 64-65, wherein the first transparent substrate has superior mechanical properties compared to the second transparent substrate.

68. The optical interconnect module of any one of claims 45-67, wherein an alignment mark is situated on or directly beneath the second major surface and helps to position the optical block on the second major surface.

69. The optical interconnect module of claim 68, wherein the alignment mark is written during the same processing step as the internal optical element.

70. A method of assembling a carrier subassembly comprising:mounting an electrooptic component on a first major surface of a transparent carrier, wherein the electrooptic component has an active area which is configured to emit or detect an optical beam that propagates through the transparent carrier; aligning a processing head of a laser processing tool with the active area; and defining an internal optical element within the transparent carrier, wherein the internal optical element is in optical alignment with the active area of the electrooptic component.

71. The method of assembling a carrier subassembly of claim 70, wherein the active area of the electrooptic component is a plurality of active areas.

72. The method of assembling a carrier subassembly of claim 71, wherein each of the plurality of active areas has a corresponding internal optical element.

73. The method of assembling a carrier subassembly of any one of claims 70-72, wherein the electrooptic component is a plurality of electrooptic components.

74. The method of assembling a carrier subassembly of claim 73, wherein all active areas in each of the plurality of electrooptic component have a corresponding internal optical element.

75. The method of assembling a carrier subassembly of any one of claims 70-74, wherein the active area is energized during the alignment of the processing head.

76. The method of assembling a carrier subassembly of any one of claims 70-74, wherein the active area is not energized during the alignment of the processing head.

77. The method of assembling a carrier subassembly of claim 76, wherein the processing head is aligned with a contact ring that surrounds or substantially surrounds the active area.

78. The method of assembling a carrier subassembly of any one of claims 71-77, wherein each active area of the plurality of active areas has its corresponding internal optical elementindividually written so that each internal optical element is in optical alignment with its corresponding active area.

79. The method of assembling a carrier subassembly of any one of claims 70-78, wherein the electrooptic component is a laser and the active area of the laser is configured to emit an optical beam that is collimated by the internal optical element.

80. The method of assembling a carrier subassembly of any one of claims 70-78, wherein the electrooptic component is a photodetector and an optical beam received by the active area of the photodetector is focused by the internal optical element.

81. The method of assembling a carrier subassembly of any one of claims 70-79, wherein the defining of the internal optical element is achieved by scanning a focal spot of a processing optical beam emitted by the laser processing tool.

82. The method of assembling a carrier subassembly of any one of claims 70-81, wherein the internal optical element is an internal diffractive optical element.

83. The method of assembling a carrier subassembly of claim 82, wherein the internal diffractive optical element comprises a Fresnel zone plate.

84. The method of assembling a carrier subassembly of any one of claims 70-81, wherein the optical element is an internal refractive optical element.

85. The method of assembling a carrier subassembly of any one of claims 70-81, wherein the optical element is a combination of an internal diffractive optical element and an internal refractive optical element.

86. The method of assembling a carrier subassembly of any one of claims 70-85, wherein the transparent carrier comprises a plurality of transparent substrates bonded together to form a unitary structure.

87. The method of assembling a carrier subassembly of claim 86, wherein the plurality of transparent substrates comprises a first transparent substrate and a second transparent substrate, the first transparent substrate forms the first major surface and the second transparent substrate forms the second major surface.

88. The method of assembling a carrier subassembly of claim 87, wherein the internal optical element is located within the second transparent substrate.

89. The method of assembling a carrier subassembly of any one of claims 87-88, wherein the first transparent substrate has superior mechanical properties compared to the second transparent substrate.

90. The method of assembling a carrier subassembly of any one of claims 70-89, wherein an alignment mark is situated on or directly beneath the second major surface and helps to position the optical block on the second major surface.

91. The method of assembling a carrier subassembly of claim 90, wherein the alignment mark is written by the laser processing tool during the same processing step as the internal optical element.

92. A method of assembling a carrier subassembly comprising: mounting an electrooptic component having a plurality of active areas on a first major surface of a transparent carrier, wherein each active area of the plurality of active areas is configured to emit or detect a corresponding optical beam that propagates through the transparent carrier; aligning a processing head of a laser processing tool with a first active area of the plurality of active area; defining a first internal optical element within the transparent carrier using the laser processing tool, wherein the first internal optical element is in optical alignment with the first active area of the electrooptic component; and repeating the aligning and defining steps for each active area of the plurality of active areas.

93. The method of assembling a carrier subassembly of claim 92, wherein the electrooptic component is a laser and each active area of the plurality of active areas is configured to emit a corresponding optical beam.

94. The method of assembling a carrier subassembly of claim 93, wherein each of the emitted corresponding optical beams is collimated.

95. The method of assembling a carrier subassembly of any one of claims 93-94, wherein each of the emitted corresponding optical beams has an optical axis and each optical axis is oriented to be perpendicular to a second major surface of the transparent carrier, opposed to the first major surface, within a manufacturing tolerance.

96. The method of assembling a carrier subassembly of any one of claims 92-95, wherein the internal optical element is an internal diffractive optical element.

97. The method of assembling a carrier subassembly of claim 96, wherein the internal diffractive optical element comprises a Fresnel zone plate.

98. The method of assembling a carrier subassembly of any one of claims 92-95, wherein the internal optical element is an internal refractive optical element.

99. The method of assembling a carrier subassembly of any one of claims 92-95, wherein the internal optical element is a combination of an internal diffractive optical element and an internal refractive optical element.

100. The method of assembling a carrier subassembly of any one of claims 92-99, wherein the transparent carrier comprises a plurality of transparent substrates bonded together to form a unitary structure.

101. The method of assembling a carrier subassembly of claim 100, wherein the plurality of transparent substrates comprises a first transparent substrate and a second transparent substrate, the first transparent substrate forms the first major surface and the second transparent substrate forms the second major surface.

102. The method of assembling a carrier subassembly of claim 101, wherein the optical element is located within the second transparent substrate.

103. The method of assembling a carrier subassembly of any one of claims 101-102, wherein first transparent substrate has superior mechanical properties compared to the second transparent substrate.

104. The method of assembling a carrier subassembly of any one of claims 92-103, wherein an alignment mark is situated on or directly beneath the second major surface and helps to position the optical block on the second major surface.

105. The method of assembling a carrier subassembly of claim 104, wherein the alignment mark is written by the laser processing tool during the same processing step as the optical element.

106. A carrier subassembly comprising: a transparent carrier having a first major surface and an opposed second major surface; an electrooptic component having an active area, wherein the electrooptic component is mounted to the first major surface; and a surface optical element situated on at least one of the first or second major surfaces, wherein the surface optical element is optically aligned with the active area of the electrooptic component.

107. The carrier subassembly of claim 106, wherein the electrooptic component has a plurality of active areas and a plurality of surface optical elements, wherein each surface optical element is individually defined based at least in part on position of each active area.

108. A method of assembling a carrier subassembly comprising defining a plurality of optical elements between or on a first major surface or an opposed second major surface of a transparent carrier; aligning a placement head of a die bonding tool with the plurality of optical elements; and mounting an electrooptic component having a plurality of active areas on the first major surface of the transparent carrier with the placement head, wherein each active area of the plurality of active areas is configured to emit or detect a corresponding optical beam that propagates through the transparent carrier and each of the plurality of active areas is in optical alignment with each of the plurality of optical elements.

109. An optical block subassembly comprising: an optical block, wherein the optical block has a bottom surface and a side surface configured to transmit an optical beam, a plurality of optical waveguides affixed to the optical block; and a plurality of optical elements, wherein each of the plurality of optical elements is associated with a corresponding optical waveguide and a location of each of the plurality of optical elements is individually defined at least in part by a position of each of the optical waveguides.

110. The optical block subassembly as recited in claim 109, wherein the position of each optical waveguide is determined by a processing tool and the location of the associated optical element is defined by a position of a processing head of the processing tool.

111. The optical block subassembly as recited in claim 109 or 110, wherein each optical element is defined on a surface of the optical block by additive manufacturing.

112. The optical block subassembly as recited in claim 111, wherein the surface is the bottom surface or the side surface and the optical element is a refractive lens.

113. The optical block subassembly as recited in claim 111, wherein the surface is a reflective surface configured to redirect the optical beam and the optical element is a curved mirror.

114. The optical block subassembly as recited in claim 109 or 110, wherein each optical element is defined by inducing a spatially localized refractive index change within the optical block.

115. The optical block subassembly as recited in any one of claims 109 to 112, wherein the plurality of optical waveguides is a plurality of optical fibers arranged as an optical fiber ribbon cable.

116. The optical block subassembly as recited in any one of claims 109 to 115, wherein and the location of each of the plurality of optical elements is individually defined at least in part by a position of an alignment mark or feature on the optical block.

117. The optical block subassembly as recited in claims 116, wherein the position of the alignment mark or feature is determined by the processing tool.

118. A method of assembling an optical block subassembly comprising: affixing a plurality of optical waveguides on an optical block; aligning a processing head of a processing tool with a first optical waveguide of the plurality of optical waveguides; defining a first optical element within or on a surface of the optical block using the processing tool, wherein the first optical element is in optical alignment with the first optical waveguide; and repeating the aligning and defining steps for each optical waveguide of the plurality of optical waveguides.

119. The method of assembling an optical block subassembly of claim 118, wherein the defining of the optical element is achieved by scanning a focal spot of a processing optical beam emitted by a laser processing tool.

120. The method of assembling an optical block subassembly of claim 118, wherein the defining of the optical element is achieved by forming a curved mirror on a reflective surface of the optical block by an additive manufacturing process.

121. The method of assembling an optical block subassembly of claim 118, wherein the defining of the optical element is achieved by forming a refractive lens on a bottom or side surface of the optical block by an additive manufacturing process.

122. An optical interconnect module comprising: a carrier subassembly, wherein the carrier subassembly comprises an electrooptic element is mounted to a transparent substrate; an optical block subassembly, wherein an optical waveguide is affixed to the carrier subassembly; and an optical element, wherein the optical element is configured to help optically couple an optical beam between the electrooptic element and the optical waveguide and the optical element is defined based at least in part on a position of the electrooptic element or the optical waveguide.

123. The optical interconnect module as recited in claim 122, wherein the optical element is located on a surface of or within the transparent substrate.

124. The optical interconnect module as recited in claim 122, wherein the optical element is located on a surface of or within the optical block.

125. The optical interconnect module as recited in any one of claims 122 to 124, wherein the optical waveguide is a plurality of optical waveguides, the electrooptic element is a plurality of electrooptic elements, and the optical element is a plurality of optical elements and each of the plurality of optical elements helps optically couple an associated electrooptic element of the plurality of electrooptic elements with an associated optical waveguide of the plurality of optical waveguides.

126. The optical interconnect module as recited in any one of claims 122 to 125, wherein additive manufacturing or laser processing is used to define the optical element.

127. The optical interconnect module as recited in any one of claims 122 to 126, further comprising an alignment feature on the carrier subassembly and a mating alignment feature on the optical block subassembly, wherein mating the alignment feature and mating alignment feature places electrooptic element and the optical waveguide in optical assignment.

128. The optical interconnect module as recited in claims 127, wherein either the alignment feature or the mating alignment feature is defined at least in part by an additive manufacturing process.

129. The optical interconnect module as recited in claim 122 to 128, wherein each optical element is defined on a surface of the optical block or the transparent carrier by additive manufacturing.

130. The optical interconnect module as recited in claim 129, wherein the surface is a bottom surface or a side surface of the optical block and the optical element is a refractive lens.

131. The optical interconnect module as recited in claim 129, wherein the surface is a reflective surface on the optical block configured to redirect the optical beam and the optical element is a curved mirror.

132. The optical interconnect module as recited in claim 129, wherein the surface is a top surface of the transparent carrier and the optical element is a refractive lens.

133. The optical interconnect module as recited in any one of claims 122 to 128, wherein the optical element is defined by inducing a spatially localized refractive index change within the optical block or transparent carrier.

134. The optical interconnect module as recited in any one of claims 122 to 133, wherein the electrooptic element is a plurality of electrooptic elements each having an active areas and the optical element is a plurality of optical elements, wherein each optical element of the plurality of optical elements is individually defined based at least in part on position of each active area.

135. An optical coupling assembly comprising:a transparent carrier having a first major surface and an opposed second major surface; an electrooptic component having an active area mounted to the first major surface and configured to emit an optical beam through the transparent carrier or detect an optical beam transmitted through the transparent carrier; an optical block mounted on the second major surface; a core of an optical waveguide in optical communication with the active area; and an optical element situated between the electrooptic component and the optical waveguide, wherein a location of the optical element is based at least in part on a position of the active area or the core of the optical waveguide.

136. The optical coupling assembly as recited in claim 135, wherein the optical waveguide is a plurality of optical waveguides, the electrooptic component is a plurality of electrooptic components each having an associated active area, and the optical element is a plurality of optical elements and each of the plurality of optical elements helps optically couple an associated electrooptic component of the plurality of electrooptic components with an associated optical waveguide of the plurality of optical waveguides.

137. The optical coupling assembly as recited in claim 136, wherein additive manufacturing or laser processing is used to define each optical element of the plurality of optical elements.

138. An optical block subassembly comprising: an optical block, wherein the optical block has a bottom surface and a side surface configured to transmit an optical beam, an alignment feature on the side surface configured to mate with an attachable / detachable optical fiber cable; and a plurality of optical elements, wherein each of the plurality of optical elements is configured to be associated with a corresponding optical waveguide of the attachable / detachable optical fiber cable and a location of each of the plurality of optical elements is individually defined at least in part by a position of the alignment feature.

139. An optical coupling assembly comprising:a transparent carrier having a first major surface and an opposed second major surface; a plurality of electrooptic components mounted to the first major surface, each electrooptic component having an active area; and a plurality of internal optical elements situated within the transparent carrier between the first and second major surfaces, wherein each internal optical element is individually aligned with a corresponding active area of the plurality of electrooptic components, such that each internal optical element's position is customized based on the position of its corresponding active area independent of the positions of other internal optical elements.

140. A method of manufacturing an optical coupling assembly comprising: mounting a plurality of electrooptic components to a first major surface of a transparent carrier, each electrooptic component having an active area; for each active area of the plurality of electrooptic components: individually aligning a processing head of a laser processing tool with that active area; and defining an internal optical element within the transparent carrier at a position optimized for that specific active area independent of the positions of other internal optical elements, wherein the resulting plurality of internal optical elements are each individually customized for their corresponding active areas without compromise for alignment with other active areas.

141. An optical coupling assembly comprising: a transparent carrier having a first surface and an opposed second surface; a plurality of electrooptic components mounted to the first surface and spaced apart from each other in a spaced array, each electrooptic component having multiple active areas; an optical block mounted to the second surface of the transparent carrier; a plurality of optical waveguides supported by the optical block; and a plurality of optical elements situated within the transparent carrier between the first and second surfaces, whereineach optical element is individually written and aligned with respect to a corresponding active area after mounting of the electrooptic components and before mounting of the optical block, and optical elements associated with transmit channels provide collimated optical beams in a region between the transparent carrier and optical block to accommodate lateral positioning tolerances between the transparent carrier and optical block while maintaining optical coupling efficiency.

142. A method of manufacturing an optical coupling assembly comprising: mounting a plurality of electrooptic components to a first surface of a transparent carrier, each electrooptic component having multiple active areas; for each active area: determining a position of the active area; aligning a laser processing tool with the determined position; writing a customized optical element within the transparent carrier between the first surface and an opposed second surface using the laser processing tool, wherein, for active areas corresponding to transmit channels, the customized optical element is configured to provide a collimated optical beam; writing an alignment feature on or near the second surface of the transparent carrier using the same laser processing tool while maintaining alignment with the active area; and mounting an optical block supporting optical waveguides to the second surface of the transparent carrier using the alignment features to achieve registration between the optical block and transparent carrier.

143. An optical interconnect module comprising: a carrier subassembly comprising a plurality of active areas; an optical block subassembly comprising a plurality of optical waveguides, wherein each of the plurality of active areas is in optical alignment with an associated optical waveguide of the plurality of optical waveguides; and a plurality of individually defined optical elements, wherein each individually defined optical element of the plurality of optical elements is in optical alignment with an active area andits associated optical waveguide and a position of each individually defined optical element is based on a position of its associated active area independent of the position of other active areas.

144. The optical interconnect module as recited in claim 143, wherein the plurality of active areas are situated on a top surface of an electrooptic component.

145. The optical interconnect module as recited in claim 144, further comprising a transparent carrier and the electrooptic component is flip-chip mounted to a first major surface of the transparent carrier and configured such that optical signals emitted by or received by the plurality of active areas pass through the transparent carrier.

146. The optical interconnect module as recited in claim 145, wherein the carrier subassembly has a carrier subassembly alignment feature and the optical block subassembly has an optical block subassembly alignment feature registered to the carrier subassembly alignment feature.

147. The optical interconnect module as recited in claim 146, wherein the carrier subassembly alignment feature directly registers with the optical block subassembly alignment feature registered to the carrier subassembly alignment feature to help enable optical alignment between the plurality of active areas and the plurality of optical waveguides.

148. The optical interconnect module as recited in claim 146, further comprising an optical block guide positioned between the carrier subassembly and optical block subassembly, wherein the carrier subassembly alignment feature directly registers with a bottom alignment feature of the optical block guide and the optical block subassembly alignment features directly registers with a top alignment feature of the optical block guide.

149. The optical interconnect module as recited in any one of claims 146-148, wherein the carrier subassembly alignment feature is fabricated during the same processing step used to fabricate the plurality of individually defined optical elements.

150. The optical interconnect module as recited in any one of claims 145-149, wherein the plurality of individually defined optical elements is situated within or on a second major surface opposed to the first major surface of the transparent carrier.

151. The optical interconnect module as recited in any one of claims 145-149, wherein the optical block subassembly comprises an optical block and the plurality of individually defined optical elements is situated within or on a surface of the optical block.

152. The optical interconnect module as recited in any one of claims 145-149, wherein the plurality of individually defined optical elements comprises a first set of individually defined optical elements situated within or on a surface of the optical block and a second set of individually defined optical elements situated within or on a second major surface opposed to the first major surface of the transparent carrier.

153. A wafer assembly comprising: a plurality of cojoined individual transparent carrier subassemblies, each individual transparent subassembly comprising; a plurality of active areas; and a plurality of individually defined optical elements, wherein each individually defined optical element of the plurality of optical elements is in optical alignment with an active area of the plurality of active areas and a position of each individually defined optical element is based on a position of its associated active area independent of the position of other active areas.

154. A method of manufacturing a plurality of carrier subassemblies, the method comprising: providing a wafer comprising a transparent material, the wafer defining a plurality of distinct carrier subassembly sites; at each of the plurality of distinct carrier subassembly sites on the wafer: i) mounting at least one electrooptic component having an active area to a first major surface of the wafer; andii) defining at least one optical element within the wafer or on a second major surface of the wafer, the optical element being optically aligned with the active area; and subsequently singulating the wafer to separate the plurality of carrier subassemblies, each comprising the at least one electrooptic component and the at least one optical element defined at its respective site.

155. The method of claim 154, further comprising, at each of the plurality of distinct carrier subassembly sites, defining at least one alignment feature on or near the second major surface of the wafer using the same processing tool used to define the at least one optical element.

156. A method of aligning an optical block subassembly with a carrier subassembly, the method comprising: providing the carrier subassembly, the carrier subassembly comprising a first alignment feature on a top surface thereof; providing the optical block subassembly, the optical block subassembly comprising a second alignment feature on a bottom surface thereof; providing an optical block guide having a body, a bottom guide feature configured to mate with the first alignment feature, and a top guide feature configured to mate with the second alignment feature; engaging the first alignment feature of the carrier subassembly with the bottom guide feature of the optical block guide; and engaging the second alignment feature of the optical block subassembly with the top guide feature of the optical block guide such that the optical block subassembly is aligned with the carrier subassembly via the optical block guide.

157. The method of claim 156, wherein at least one of the first alignment feature or the second alignment feature comprises a feature protruding from its respective subassembly surface, and wherein the corresponding bottom guide feature or top guide feature comprises a slot configured to receive the protruding feature.

158. An optical block guide for aligning an optical block subassembly with a carrier subassembly, the optical block guide comprising: a body formed of a transparent material; a top surface having at least one top alignment feature configured to mechanically register with a corresponding alignment feature on a bottom surface of the optical block subassembly; and a bottom surface having at least one bottom alignment feature configured to mechanically register with a corresponding alignment feature on a top surface of the carrier subassembly.

159. An optical coupling assembly comprising: a transparent carrier having a first surface and an opposed second surface; a plurality of electrooptic components mounted to the first surface and spaced apart from each other in a spaced array, each electrooptic component having multiple active areas; an optical block mounted to the second surface of the transparent carrier; a plurality of optical waveguides affixed to the optical block; and a plurality of optical elements situated within or on a surface of the optical block, wherein each optical element is individually defined and aligned with respect to a corresponding optical waveguide of the plurality of optical waveguides after affixing of the plurality of optical waveguides to the optical block, and each optical element's location is customized based on the position of its corresponding optical waveguide independent of the positions of other optical waveguides to maintain optical coupling efficiency between the active areas and the optical waveguides despite variations in optical waveguide positions.

160. An optical coupling assembly comprising: a transparent carrier having a first surface and an opposed second surface; a plurality of electrooptic components mounted to the first surface and spaced apart from each other in a spaced array, each electrooptic component having multiple active areas including active areas associated with receive channels; an optical block mounted to the second surface of the transparent carrier; a plurality of optical waveguides supported by the optical block; anda plurality of optical elements situated within the transparent carrier between the first and second surfaces, wherein each optical element is individually written and aligned with respect to a corresponding active area after mounting of the electrooptic components and before mounting of the optical block, and optical elements associated with receive channels are configured to focus an incoming optical beam, originating from a corresponding optical waveguide and passing through the optical block, onto the corresponding active area of the receive channel, thereby maintaining optical coupling efficiency despite positioning variations of the electrooptic components.

161. A carrier subassembly comprising: a transparent carrier having a first major surface and an opposed second major surface; an electrooptic component mounted relative to the first major surface, the electrooptic component comprising an active area and a substrate, wherein the electrooptic component is configured for optical signal transmission between the active area and the transparent carrier through the substrate of the electrooptic component, and wherein the substrate of the electrooptic component is substantially transparent at an operating wavelength of the optical signal; and at least one optical element situated within the transparent carrier or on the second major surface, the at least one optical element being optically aligned with the active area via the optical signal path through the substrate of the electrooptic component.

162. A method of manufacturing an optical coupling assembly, the method comprising: providing a transparent carrier having a first major surface and an opposed second major surface; mounting an electrooptic component relative to the first major surface, the electrooptic component comprising an active area and a substrate substantially transparent at an operating wavelength, wherein the electrooptic component is configured for optical signal transmission between the active area and the transparent carrier through the substrate of the electrooptic component;aligning a processing head of a processing tool with the active area, wherein alignment accounts for the optical signal path through the substrate of the electrooptic component; and defining at least one optical element within the transparent carrier or on the second major surface using the processing tool, wherein the at least one optical element is optically aligned with the active area via the optical signal path through the substrate of the electrooptic component.

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