Optical block, optical interface and passively aligned optical interconnection system

Abstract

This invention describes a system and method for establishing an optical connection between an optical fiber and an optoelectronic element using an optical block. The optical block is part of an optical interconnect module comprising a detachable optical interface of one or more optical fibers. The optical interface may include two configurations: a first configuration and a second configuration. The first configuration includes an exposed optical path, and the second configuration includes a sealed optical path. A common optical interconnect module and a common optical block can be used in both configurations. The optical block may include alignment features that facilitate accurate alignment of the optical block with a mating element relative to six degrees of freedom.

Description

An optical module providing optical communication between an optical fiber and an optoelectronic component This disclosure relates to a system and method for optically connecting an optical fiber and an optoelectronic component using an optical module. Cross-reference to related applications This application claims the benefit of U.S. Patent Application No. 63 / 468,858, filed May 25, 2023, and U.S. Patent Application No. 63 / 608,518, filed Dec. 11, 2023. The entire contents of each application are incorporated herein by reference. Optical interconnect modules, such as optical transmitters, optical receivers, and optical transceivers, are widely used in high-speed data transmission and reception using optical fibers as part of an optical data communication system. An optical transceiver supports bidirectional optical communication, i.e., the optical transceiver can transmit and receive optical signals. An optical transmitter supports unidirectional optical communication, and an optical transmitter can only transmit optical signals. An optical receiver also supports unidirectional optical communication, i.e., an optical receiver can only receive optical signals. An optical interconnect module typically includes a plurality of independent channels, each of which can transmit or receive signals via an optical fiber. Typically, one optical fiber carries the transmitted optical signal, and individual optical fibers carry the received optical channels. In some applications, the transmitted and received signals can be combined and propagated through a single optical fiber. Optical interconnect modules typically use optical components to define the optical connection between optoelectronic components in the module and use optical fibers to carry optical signals to and from the module. Optical components typically include alignment features that facilitate establishing optical communication between the optoelectronic components and the optical fibers. The optical fiber can be permanently attached to the optical interconnect module (so-called pigtail configuration), or the optical fiber can be attachable and detachable. The attachable / detachable configuration is typically desirable because it allows the optical interconnect module to be connected to optical fiber cables of different lengths by simply swapping out the optical fiber cable. The attachable / detachable configuration also facilitates the manufacture and shipping of the optical interconnect module because there is no need to prepare for handling the cable hanging from the module. Optical interconnect modules are used in many types of operating environments. One area of application is within data centers or other applications located within environmentally controlled enclosed areas such as buildings. In such applications, the operating environment is controlled to avoid excessive or low temperatures or humidity, minimize airborne dust, minimize shock and vibration, and isolate the module from liquids. That is, the optical interconnect module will not be exposed to environmental conditions that can damage the interconnect module. In other applications, the optical interconnect module needs to operate in a more harsh environment. Such applications include, but are not limited to, mobile applications in vehicles, aircraft, or ships. An optical interconnect module operating in a harsh environment requires features that a module operating in a benign environment does not, such as sealing the optical interface between the module and an attachable / detachable optical cable. The sealing feature increases the cost of the harsh environment module, which is not needed in a benign environment module; however, it is desirable if the components and manufacturing processes of the two module types are as similar as possible to achieve economies of scale. Examples of prior art optical interconnect modules are described in U.S. Patent Application Publication No. 2023 / 0393355. In some embodiments, the optical interconnect module described in U.S. Patent Application Publication No. 2023 / 0393355 includes a sealed optical path that allows operation in a contaminated environment. Sealing of the optical path is achieved by an optically transparent plate that makes physical contact with the end face of the optical fiber positioned within the ferrule when the ferrule mates with the optical interconnect module. Due to the physical contact, contaminants cannot reach the optical path between the optical fiber end face and the transparent optical plate. The optical interconnect module has an optical design that enables effective optical coupling between the optical fiber within the ferrule and the optoelectronic components (e.g., lasers and photodetectors) of the module. The optical design must account for diffraction of the light beam as it propagates along the optical path through the optically transparent plate. For the receive channel, the light beam diverges as it propagates through the optically transparent plate, and for the transmit channel, the light beam converges as it propagates through the optically transparent plate. If the optically transparent plate is not in the optical path, the optical design will no longer effectively couple the light between the optical fiber and the optoelectronic components. Although the optical designs described in U.S. Patent Application Publication No. 2023 / 0393355 and other prior art work well for applications that require a sealed optical path, they are unnecessarily complex and expensive for benign environment applications that do not require a sealed optical path. Accordingly, there is a need to provide an optical block that can provide a multi-functional optical interface to an optical interconnect module that is low cost, easy to use, and can operate in both harsh and benign environments. In some applications, the optical block needs to maintain alignment between the optoelectronic components of the module and the mating optical fiber over a large operating temperature range. One aspect of the disclosure describes an optical block that includes a cable contact surface configured to directly receive a cable ferrule in a first configuration and indirectly receive a cable ferrule in a second configuration. Another aspect of the disclosure describes an optical block that includes a cable contact surface having a recessed area. The recessed area is located within the outer surface of the cable contact surface, and an inner surface and a protruding portion are located within the recessed area. In some embodiments, an optical block subassembly can be formed by attaching a transparent plate to the protruding portion. Another aspect of the disclosure describes an optical block that includes a cable contact surface configured to receive a removable cable assembly and a photoelectric element contact surface that includes a plurality of alignment features. The plurality of alignment features are configured to passively align the optical block against a mating surface with respect to six degrees of freedom. Another aspect of the disclosure describes an optical block that includes a cable contact surface and a photoelectric element contact surface. The cable contact surface is configured to receive a cable sleeve and includes a recessed area within the outer surface of the cable contact surface. The cable contact surface also includes an inner surface and a protruding portion located within the recessed area. The photoelectric element contact surface includes a plurality of alignment features that are configured to passively align the optical block against a mating surface with respect to six degrees of freedom. In some embodiments, an optical block subassembly can be formed by attaching a transparent plate to the protruding portion. Another aspect of the disclosure describes an optical interconnect that includes an optical block having a recessed area within a cable contact surface and a protruding portion located within the recessed area. The optical interconnect further includes a cable sleeve that includes a front surface configured to mate with the optical block. There are two mating configurations for the optical interconnect between the optical block and the cable sleeve, a first configuration and a second configuration, where the second configuration is different from the first configuration. Another aspect of the disclosure describes an optical interface that is located between a cleated optical block and a mating element. The cleated optical block includes a photoelectric element contact surface that includes at least one type-I alignment feature and a plurality of type-II alignment features extending from the photoelectric element contact surface. The mating element includes a mating surface that includes a plurality of recessed areas within the mating surface. The plurality of type-II alignment features are inserted into the plurality of recessed areas, and at least one type-I alignment feature contacts the mating surface, thereby passively aligning the cleated optical block and the mating element. Another aspect of the disclosure describes a passively aligned optical interconnect system. The system includes an optical block and a mating element. The optical block includes a photoelectric element contact surface having a plurality of optical block alignment features. The mating element includes a plurality of mating element alignment features that are configured to mate with the optical block alignment features such that when the optical block alignment features mate with the mating element alignment features, the optical block is passively aligned with the mating element in six degrees of freedom. Another aspect of the disclosure describes a method of optically interconnecting a cable ferrule and an optical interconnect module. In a first configuration, a front face of the cable ferrule contacts an outer portion of a cable contact surface of an optical block. In a second configuration, the front face of the cable ferrule contacts a transparent plate between the optical block and the cable ferrule. Additional aspects of the disclosure are shown in the specification, drawings, and claims of this application. The above and other features, elements, characteristics, steps, and advantages of the invention will become more apparent from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. As described above, it is desirable if the optical interconnect module can be used in both benign and harsh operating environments. A benign operating environment may correspond to a first configuration of an optical interface or optical interconnect. The first configuration may include an exposed optical path. A harsh operating environment may correspond to a second optical interface or optical interconnect. The second configuration may include a sealed optical path. Two configurations of the optical interconnect are described below. FIG. 1 shows a perspective view of an optical interconnect module 10 including a cable latch 29 positioned to receive or release a removable cable assembly 15. The removable cable assembly 15 can generally be inserted into the optical interconnect module 10 along a longitudinal or X direction. A lateral or Z direction can be perpendicular to a lateral or Y direction and perpendicular to the X direction. The removable cable assembly 15 can include a cable 22 and a cable ferrule 23. The cable ferrule 23 terminates one end of the removable cable assembly 15 at a front face 87. The cable 22 can contain a plurality of optical fibers. End faces of the optical fibers included in the cable 22 can be exposed at the front face 87 of the cable ferrule 23. The cable latch 29 can be carried by a module frame 52 or some other element of the optical interconnect module 10. The cable latch 29 can be arranged such that the cable latch 29 is permanently connected to the remainder of the optical interconnect module 10. The module frame 52 can include an inclined surface 90. There can be two inclined surfaces 90 symmetrically disposed about a bisecting plane parallel to the X-Z plane. The optical interconnect module 10 can include an optical block 78 configured to receive the removable cable assembly 15. To install the detachable cable assembly 15 into the optical interconnect module 10, the detachable cable assembly 15 can be inserted adjacent to the optical block 78 along the longitudinal direction such that the front face 87 of the cable sleeve 23 abuts against the optical block 78. The cable latch 29 can then be rotated downwardly about the pivot 35 to contact the rear face 89 of the cable sleeve 23 and secure the cable sleeve 23 against the optical block 78. The cable latch 29 can include cable latch edges 92. There can be two cable latch edges 92 symmetrically disposed about a bisecting plane parallel to the X-Z plane. The cable latch edges 92 can be curved as shown in FIG. 1. When the detachable cable assembly 15 mates with the interconnect module 10, two inclined surfaces 90 can each engage a corresponding cable latch edge 92 of the cable latch 29. In its closed or locked position (not shown in FIG. 1), the cable latch 29 presses against the rear face 89 of the cable sleeve 23, thereby forcing the cable sleeve 23 against the interconnect module 10. The cable latch 29 can thus provide the pressure to ensure mechanical contact between the cable sleeve 23 and the optical interconnect module 10. The cable latch 29 can be referred to as a swing latch because the cable latch 29 pivots to engage and disengage the cable sleeve 23 with the interconnect module 10. The optical interconnect module 10 depicted in FIG. 1 can be configured as an optical transceiver, but alternatively can be configured as an optical receiver or an optical transmitter. FIG. 2 shows the front face 87 of the cable sleeve 23 including two rows of optical fibers 114. The cable sleeve 23 can align the end faces 115 of a plurality of optical fibers 114 relative to one or more reference features 142 on the cable sleeve 23. The cable sleeve 23 can be an MT-type sleeve or some other sleeve type that supports optical fibers, and the cable sleeve is part of an optical interconnect system between the interconnect module 10 and the detachable cable assembly 15. In an MT-type sleeve, two precision holes serve as the reference features 142. Any suitable alignment can be used as the reference feature 142. The MT-type sleeve aligns the end faces 115 of a plurality of optical fibers 114 supported by the MT-type sleeve relative to the reference feature 142. The reference feature 142 can be two precision guide holes. The precision holes are configured to accommodate guide pins (not shown in FIG. 2). The front face 87 of the cable sleeve 23 can be divided into an inner portion 138 adjacent to the optical fiber end faces 115 and an outer portion 140 surrounding the inner portion 138. Both the inner portion 138 and the outer portion 140 can be in a common plane parallel to the Y-Z plane, which forms the front face 87 of the cable sleeve 23. As described below, the detachable cable assembly 15 can be connected to the interconnect module 10 in two different configurations. In the first configuration, the outer portion 140 of the front face can contact the interconnect module 10, and there is no contact between the inner portion 138 and the interconnect module 10. In the second configuration, the inner portion 138 of the front face 87 can contact the interconnect module 10, and there is no contact between the outer portion 140 and the interconnect module 10. FIG. 3 shows a plan view of the cable contact surface 122 of the optical block 78 according to an embodiment of the present disclosure. The cable contact surface may include a recessed area 132. The recessed area 132 may be formed by an opening in the outer surface 146 of the cable contact surface 122. The inner surface 144 and the intermediate surface may be located within the opening in the outer surface 146, and the intermediate surface may be referred to as a protrusion 130. The inner surface 144, the protrusion 130, and the outer surface 146 may be substantially planar surfaces oriented parallel to the Y-Z plane. As described below, both the protrusion 130 and the outer surface 146 may serve as reference surfaces. A plurality of lens elements 112 facing the cable may be located on the inner surface 144. The plurality of lens elements 112 facing the cable may be arranged in a row oriented along the Y direction. There may be a single row or a plurality of rows, such as two rows, three rows, four rows, or more than four rows. The lens elements 112 facing the cable may focus the light transmitted through the lens elements 112 facing the cable when the lens elements 112 facing the cable are located in the transmission channel, or collimate the light transmitted through the lens elements 112 facing the cable when the lens elements 112 facing the cable are located in the receiving channel. The protrusion 130 may completely surround the inner surface 144. The outer surface 146 may only partially surround the protrusion 130. One or more reference features, such as dowel pins 80, may be present on the cable contact surface 122. The optical block 78 may include a bottom surface 152 that is adjacent and perpendicular or substantially perpendicular to the cable contact surface 122 within manufacturing and / or measurement tolerances. The bottom surface 152 of the optical block may include one or more alignment features 154. The bottom surface 152 may be regarded as a photoelectric element contact surface because the bottom surface 152 is configured to transmit light from or propagate light to a photoelectric element. FIG. 4 shows a perspective view of the bottom surface 152 of the optical block 78 according to an embodiment of the present disclosure. The optical block 78 may include a bottom socket 180. The bottom socket 180 defines a cavity in the bottom surface 152 of the optical block 78. A lens array (not shown in FIG. 4) may be located in the bottom socket 180. The bottom surface 152 of the optical block 78 may also include one or more alignment features 154. The alignment features 154 may be any suitable alignment device and, as shown in FIG. 4, may be in the form of a plurality of pedestals 161, the bottom surfaces 172 of which are configured to contact a mating surface (not shown in FIG. 4). The bottom surfaces 172 may be substantially planar. As shown in FIG. 4, there may be three pedestals; however, in some embodiments, more pedestals 161 may be used. For proper operation of the optical interconnection module 10, the optical block 78 must be aligned with the underlying mating surface in three position dimensions and three angular dimensions. The three position dimensions may be the X, Y, and Z axes, which are oriented along the longitudinal, lateral, and transverse directions, respectively. The three angular dimensions may correspond to rotations about the X, Y, and Z axes and may be represented as longitudinal rotation (γ x), lateral rotation (γ y ), and transverse rotation (γ z ). The alignment feature 154 helps to achieve accurate mating of the optical block 78 with the underlying mating component along at least some of the three positional dimensions and the three angular dimensions. As described below, in some embodiments, the alignment feature helps to achieve passive alignment of the optical block in all six of these dimensions, while in other embodiments, some dimensions may be passively aligned and some dimensions actively aligned. The support 161 depicted in FIG. 4 helps to accurately align the optical block 78 against a planar or substantially planar mating surface within manufacturing and / or measurement tolerances by bringing each of the supports 161 into contact with the mating surface. To help ensure accurate orientation, the support 161 can be in direct contact with the mating surface without any intervening adhesive layer. The support 161 helps to ensure accurate positional alignment in the transverse or Z direction, and accurate angular alignment in the longitudinal and lateral rotation orientations (γ x and γ y ). Alignment in these three dimensions can account for type I alignment, and the support 161 can be considered a type I alignment feature. The support 161 does not provide passive alignment of the optical block with the planar mating surface in the longitudinal or X direction, the lateral or Y direction, and the transverse rotation orientation γ z . Alignment features that help with alignment in these dimensions can be considered type II alignment features. As described below, the support 161 in combination with type II alignment features can achieve passive alignment in all six degrees of freedom. Alignment features can include any suitable aligners, including for example type I alignment features and type II alignment features. Different types of aligners can be used in combination with each other such that the combination of aligners achieves passive alignment in all six degrees of freedom. The optical block 78 depicted in FIG. 4 can be considered a non-cleated optical block 178. Here, the non-cleated optical block 178 refers to an optical block 78 that does not include type II alignment features on the optical block 78. Thus, the non-cleated optical block 178 must be aligned with the mating component using some other structure other than the type II alignment features on the bottom surface 152. For example, the non-cleated optical block 178 can be actively aligned with features on the mating component using vision-guided positioning and pick-and-place tools. FIG. 5 shows a plan view of the cable contact surface 122 of the optical block 78 according to a specific example of the present disclosure. Many of the features shown in FIG. 5 are similar to the features shown in FIG. 3, and for the sake of brevity, the description of those features will not be repeated here. The optical block 78 can be a wedge-shaped optical block 278 including a plurality of wedges 157 on the bottom surface 152 of the optical block 78. The wedges 157 can be regarded as alignment features 154 on the bottom surface 152. In particular, the wedges 157 can be type-II alignment features 156, which help to achieve passive alignment of the wedge-shaped optical block 278 with mating components (not shown in FIG. 5) in the upper and lower layers in the longitudinal or X direction, the lateral or Y direction, and the transverse rotation orientation γ z As explained above, the alignment features 154 are not limited to the wedges 157 or type-II alignment features, and can include any suitable aligners. As will be explained in more detail below, the wedge-shaped optical block 278 can be passively aligned with the mating components because the wedges 157 can be mechanically aligned with the features in the mating components. This may require less expensive tools than those required to place the non-wedge optical block 178 on the mating components. The wedge-shaped optical block 278 can have a shorter placement time, which helps to achieve lower-cost manufacturing. The wedge-shaped optical block 278 can also include a support 161 similar to the support described in the previous specific example. FIG. 6 shows a perspective view of the bottom surface 152 of the optical block 78. The optical block 78 is a wedge-shaped optical block 278 including a plurality of alignment features 154 on its bottom surface 152. The alignment features can be classified as type-I alignment features 160 and / or type-II alignment features 156. The type-I alignment features 160 can help to ensure accurate position alignment in the transverse or Z direction, and accurate angular alignment in the longitudinal and lateral rotation orientations (γ x and γ y ). The type-II alignment features 154 can help to ensure accurate position alignment in the longitudinal or X direction, the lateral or Y direction, and the transverse rotation orientation γ zAccurate angular alignment above. Referring to the coordinate system in Figure 6, the mating direction will be the Z direction. The Type I alignment feature 160 can also help to position the optical block 78 in the mating direction. There can be an equal number of Type I alignment features 160 and Type II alignment features 156, or there can be different numbers of Type I alignment features 160 and Type II alignment features 156. For example, there can be four Type I alignment features 160 and three Type II alignment features 156, as shown in Figure 6; however, there can be more or fewer numbers of alignment features of both types. The Type II alignment features 156 can have different forms or can have the same form and different orientations. For example, the form can be a wedge 157, where one wedge is a longitudinally extending wedge 162 and one wedge is a laterally extending wedge 158. As shown in Figure 6, there can be four Type I alignment features; however, there can be more or fewer numbers of Type I alignment features 160. At least three Type I alignment features can be used to accurately orient the optical block 78 in the longitudinal rotation orientation γ x and the lateral rotation orientation γ y above. The Type I alignment feature 160 can be a plurality of supports 161, which provide a small gap between the bottom surface 152 and the mating surface (not shown in Figure 6 but shown in Figure 9) when the plurality of supports 161 contact the mating surface and when the optical block 78 mates with the mating surface. For example, within manufacturing and / or measurement tolerances, the gap can range between about 10 micrometers and about 100 micrometers. The gap can be large enough to allow material to easily fill the gap, but not so large as to have excessive filler material and slender supports 161. All supports 161 can be the same within manufacturing tolerances. Figure 7 shows a bottom plan view of a wedge-shaped optical block 278 according to an embodiment of the present disclosure. Type I alignment features 160 and Type II alignment features 156 are disposed on the bottom or optoelectronic element contact surface 124. Some of the Type II alignment features 156 may be arranged in pairs. Specifically, there may be a pair of laterally extending wedges 158. The pair of laterally extending wedges may be arranged along a laterally extending bisector 171 parallel to the lateral direction or Y-axis. Thus, the individual laterally extending wedges 158 may extend along the lateral direction, and all the laterally extending wedges 158 may be arranged along a common laterally extending bisector 171. The inclusion of the laterally extending wedges 158 arranged along the common laterally extending bisector 171 allows some freedom of movement in the lateral direction while constraining movement in the orthogonal longitudinal direction. This arrangement allows any increase or contraction in the distance between the laterally extending wedges 158, or more generally any pair of Type II alignment features 156, due to temperature swings or manufacturing tolerances to be permitted with minimal or no stress in the alignment features. The laterally extending wedges 158 may be spaced apart along the lateral direction by at least half the width of the wedge-shaped optical block 278 so as to sufficiently define the orientation of the laterally extending bisector 171. The longitudinally extending wedges 162 may extend along a longitudinally extending bisector 173 parallel to the longitudinal direction or X-axis and are thus orthogonal to the laterally extending bisector 171 passing through the laterally extending wedges 158. The longitudinally extending wedges 162 may be longer than the laterally extending wedges 158 to better define the direction of the longitudinally extending bisector 173. The laterally extending wedges 158 and the longitudinally extending wedges 162 thus constrain movement in both the lateral and longitudinal directions. The Type II alignment features 156 may be arranged asymmetrically with respect to the laterally extending bisector 171. Specifically, a single longitudinally extending wedge 162 may be located on a first side of the laterally extending bisector 171 and no longitudinally extending wedge may be located on a second, opposite side of the laterally extending bisector 171. The laterally extending bisector 171 and the longitudinally extending bisector 173 intersect at an intersection point 175, which may be regarded as a virtual center. The virtual center 175 is a motion-determining point around which thermal expansion and manufacturing dimensional changes occur freely. The virtual center 175 may be centered relative to a plurality of optical paths 177 propagating through the wedge-shaped optical block 278. The plurality of optical paths may be arranged symmetrically about the virtual center. In Figure 7, sixteen optical paths 177 are shown; however, there may be as many optical paths as there are lenses in the array of cable-facing lenses 112 (see Figure 5). Centering the virtual center 175 relative to the optical paths 177 helps to minimize misalignment of the optical paths 177 due to temperature changes and manufacturing tolerances. The Type II alignment features 156 may be widely separated to help control in-plane rotation about the virtual center 175 between the wedge-shaped optical block 278 and the mating element, i.e., lateral or about the Z-axis (γ z Rotation of ( ). Although the type II alignment feature 156 has a stress-free degree of freedom of movement along a particular axis, these features are not infinitesimal, and thus stress can also exist along an orthogonal axis perpendicular to the extension direction. However, since the type II alignment feature 156 is much shorter along the orthogonal axis perpendicular to its extension direction, the stress caused by the coefficient of thermal expansion (CTE) mismatch is greatly reduced and can generally be ignored. Manufacturing tolerance is a problem for the dimensions of the type II alignment feature 156 in the direction orthogonal to its extension direction. This dimension typically requires the tightest tolerances consistent with the manufacturing method used to fabricate the wedge-shaped optical block 278. In the case of molding a plastic wedge-shaped optical block 278, a tolerance of approximately 5 microns can be achieved. In other words, the basic motion design of the type II alignment feature 156 provides little or no constraint to thermal expansion in the direction aligned with the extension direction pointing to the virtual center 175, thereby eliminating most CTE and manufacturing tolerance problems along these directions. The CTE and manufacturing tolerances orthogonal to the extension direction are still problems, but can be solved by appropriate material selection, appropriate feature tolerances, and maintaining small feature sizes to minimize thermal expansion. FIG. 8 shows a cross-sectional view of a portion of the wedge-shaped optical block 278 positioned above the mating element 163 according to a specific example of the present disclosure. The wedge-shaped optical block 278 can be mated with the mating element 163 by moving the optical block in the mating direction 182 (i.e., the Z direction). FIG. 8 helps to explain the details of the alignment feature 154 and the mating element 163, which, when mated, achieve accurate positioning and angular placement of the wedge-shaped optical block 278 relative to the mating element 163. The bottom surface 152 of the wedge-shaped optical block 278 can be parallel to the X-Y plane. The type I alignment feature 160 or the support 161 can extend a distance D from the bottom surface 152 of the wedge-shaped optical block 278 s The distance D sIt can be regarded as the height of the support. The bottom surface 172 of the support 161 can be substantially planar and oriented parallel to the X-Y plane. As disclosed above, the type-II alignment feature 156 can be a wedge 157. The wedge 157 can be a longitudinally extending wedge 162 or a laterally extending wedge 158. The two types of wedges 162, 158 can have a similar cross-sectional shape, so FIG. 8 can be used to explain the operation of the two types of wedges 162, 158. The wedge 157 can be symmetric about the bisecting plane 166. For the longitudinally extending wedge 162, the bisecting plane 166 can be parallel to the X-Z plane, or for the laterally extending wedge 158, this bisecting plane can be parallel to the Y-Z plane. The laterally extending bisecting line 171 and the longitudinally extending bisecting line 173 (see FIG. 7) can be located in the bisecting plane 166. The wedge 157 can extend a distance D from the bottom surface 152 of the wedge-shaped optical block 278 B . The distance D B can be regarded as the height of the wedge 157. The wedge can include side walls 159. The profiles of the wedge side walls 159 on opposite sides of the bisecting plane 166 can be tapered such that the width of the wedge 157 at a distance D B2 from the bottom surface W S is greater than or equal to the width of the wedge at any position further away from the bottom surface 152. The side walls 159 can be divided into two sections: an upper section 168, which is adjacent to the base of the wedge 157; and a lower section 170, which is adjacent to the bottom of the wedge 157. Both the upper section 168 and the lower section 170 can be substantially planar and have different orientations. In particular, for the longitudinally extending wedge 162, the surface perpendicular to the upper section 168 can be oriented at an angle α A relative to the X-Z plane, or for the laterally extending wedge 158, this surface can be oriented at an angle α A relative to the Y-Z plane. The angle α A can be regarded as the orientation angle of the upper section 168 of the wedge 157. The orientation of the upper section 168 is such that the width W B1 of the wedge 157 at the intersection of the upper section 168 and the lower section 170 is less than the width W B2 at the height of the support 161. The longitudinally extending wedge 162 can extend a greater distance in the longitudinal direction than the laterally extending wedge 158 extends in the lateral direction. Details of mating element 163 will now be described. The mating element 163 may include a substantially planar top surface or mating surface 164 that extends in the X-Y plane, such that it can be aligned so that it is parallel or substantially parallel to the bottom surface 152 of the wedge-shaped optical block 278 within manufacturing and / or measurement tolerances. The mating surface 164 may include a recessed area 174 that includes side walls 176. The recessed area 174 may be symmetric about the bisecting plane 166. For the longitudinally extending wedge 162, the recessed area 174 may extend in the X direction, or for the laterally extending wedge 158, the recessed area may extend in the Y direction. The recessed area 174 has a depth D in the Z direction perpendicular to the X-Y plane A . At the top of the recessed area 174, the recessed area 174 may have a width W A1 . The recessed area 174 may taper at an angle α B such that the width W at the bottom of the recessed area 174 A2 is less than the width W at the top of the recessed area 174 A1 . The angle α B may be regarded as the orientation angle of the side walls 176 of the recessed area. The respective parameters defining the wedge 157 and the recessed area 174 are selected such that when the wedge 157 is inserted into the recessed area 174, the wedge 157 will fit tightly into the recessed area 174 without hitting the bottom. In particular, the width W at the intersection between the upper section 168 and the lower section 170 of the wedge 157 B1 may be selected such that the width W B1 is less than the width W at the top of the recessed area 174 A1 . This allows the wedge 157 to be easily inserted into the recessed area to begin mating the wedge-shaped optical block 278 and the mating element 163 together. The width W at the top of the recessed area A1 may be selected such that it is equal to or approximately equal to the width W at the height of the support 161 within manufacturing tolerances B2 . Mathematically, these relationships may be represented by the equations W B1 < W A1 ≈ W B2The orientation of the side wall 159 of the wedge 157 and the side wall 176 of the recessed area 174 can be selected such that the orientation angle α of the side wall of the recessed area B is less than the orientation angle α of the upper section of the wedge 157 A . Mathematically, this relationship can be expressed as α B < α A . When the wedge 157 is inserted into the recessed area 174, the wedge 157 will extend into the recessed area 174 by a distance equal to the height D of the wedge 157 B minus the height D of the gap 161 S . This insertion depth can be less than the depth D of the recessed area 174 A to avoid the wedge hitting the bottom in the recessed area 174. Mathematically, this relationship can be expressed as (D B - D S ) < D A . The advantage of the arrangement described above is the intentional partitioning of the alignment in six degrees of freedom between the type-I alignment feature 160 and the type-II alignment feature 156. This partitioning makes it easier to form and detect these features. The support 161 focuses on the height and flatness of the optical block 78 from the mating element 163. The wedge 157 focuses on the lateral or longitudinal alignment of the optical block 278 relative to the mating element 163. This is in contrast to prior art systems, such as alignment balls located in recesses with conical side walls. In such prior art systems, both types of alignment are controlled by the same set of contact surfaces. Thus, the lateral dimensions ultimately also affect the vertical alignment. The wedge 157 can deform when it is inserted into the recessed area 174 of the mating surface 164. The taper angle on the upper section 168 of the wedge 157 can be steep enough, and the wedge material soft enough, to allow the optical block 278 to rest on the support 161 when the optical block 278 is mated to the mating element 163 and to be closely aligned in the lateral or longitudinal direction into the recessed area 174 of the mating surface 164. The deformation can be elastic deformation, non-elastic deformation, or a combination of both types of deformation. The deformation of the wedge 157 in the recessed area 174 of the mating surface 164 helps to partition the degrees of freedom aligned by the type-I alignment feature 160 from those degrees of freedom aligned by the type-II alignment feature 156. Figure 9 shows a portion of the wedge-shaped optical block 278 mating with the mating element 163. In Figure 9, for clarity, many of the parameters and indicator markings shown in Figure 7 have been removed. As shown in Figure 9, when the wedge 157 is inserted into the recessed area 174, the bottom surface 172 of the support 161 rests on the mating surface 164. This arrangement enables accurate positioning of the wedge-shaped optical block 278 in the Z direction with respect to the mating surface 152. The wedge 157 can fit tightly into the recessed area 174 because the width W s at a distance D from the bottom surface 172 of the support 161 B2 is equal to or approximately equal to the width W at the top of the recessed area 174 A1 . Since the orientation angle α A of the upper section of the wedge 157 is greater than the orientation angle α B of the side wall 176 of the recessed area 174, the contact between the wedge 157 and the side wall 176 of the recessed area 174 will occur only at the top of the recessed area 174. Therefore, the only part of the wedge 157 that contacts the recessed area 174 is located on the upper section 168 of the side wall 159. Thus, the wedge 157 is accurately aligned with respect to the recessed area 174 in a direction perpendicular to the Z direction. For the laterally extending wedge 158, this direction is the X direction, and for the longitudinally extending wedge 162, this direction is in the Y direction. The recessed area 174 is oversized in a direction perpendicular to the cross-sectional view shown in Figure 9 such that the wedge is unconstrained in this direction. For the laterally extending wedge 158, the unconstrained direction is the Y direction, and for the longitudinally extending wedge 162, this direction is the X direction. By including at least one laterally extending wedge 158 and at least one longitudinally extending wedge 162 on the bottom surface 152 of the optical block 278, the optical block 278 can be accurately aligned in both the X direction and the Y direction. There can be more than one laterally extending wedge 158 and longitudinally extending wedge 162 on the bottom surface 152 of the optical block 78. For example, Figure 6 shows an optical block 78 including two laterally extending wedges 158 and one longitudinally extending wedge 158. A gap 165 exists between the bottom surface 152 of the wedge-shaped optical block 278 and the mating surface 164. The gap 165 has a height D equal to the height of the support 161 s(See FIG. 8). At least a portion of the gap 165 may be filled with a transparent adhesive 167. Alternatively, the gap 165 may be filled with a refractive index matching gel that does not have adhesive properties. In yet another specific example, the gap 165 may remain unfilled, and one or both of the bottom surface 152 or the mating surface 164 may be anti-reflection coated. These surfaces may remain uncoated if the Fresnel reflection from the bottom surface 152 and the mating surface 164 does not adversely affect the performance of the interconnect module. In particular, the transparent adhesive 167 may be present in all areas of the bottom surface 152 through which the optical signal passes. The transparent adhesive may not be present in the areas of the bottom surface 152 that include any alignment features 154, as the presence of the transparent adhesive 167 may compromise the alignment surfaces of these features. The transparent adhesive 167 may take many forms. For example, the transparent adhesive 167 may be coated onto the bottom surface 152 and / or the mating surface 164 in the form of droplets, beads, or a coating of liquid. Then, during the mating process, when the transparent adhesive 167 is compressed between the wedge-shaped optical block 278 and the mating element 163, the transparent adhesive 167 may expand laterally and longitudinally. In an alternative specific example, a transparent pressure-sensitive adhesive in the form of a sheet may be positioned in the gap 165. The thickness of the pressure-sensitive adhesive may be slightly greater than the gap 165, such that when the optical block 78 is mated with the mating element 163, the pressure-sensitive adhesive is compressed. All optical paths 177 (see FIG. 7) may propagate through the transparent adhesive 167. Only one or a plurality of optical paths 177 are shown in FIG. 9. The refractive index of the transparent adhesive 167 may be approximately equal to or between the refractive indices of the wedge-shaped optical block 278 and the mating element 163. Thus, the Fresnel reflection at the interface between the wedge-shaped optical block 278 and the transparent adhesive 167 and at the interface between the mating element 163 and the transparent adhesive 167 may be minimized. The transparent adhesiveness 167 may help to permanently fasten the wedge-shaped optical block 278 to the mating element 163. The wedge-shaped optical block 278 and the mating element 163 shown in FIGS. 5 to 9 and described above may be regarded as a passive alignment interconnect system that passively aligns the optical block 278 relative to the mating element 163 in all six degrees of freedom. The optical block 78 (with or without a wedge) can be formed from a molded polymer in a single-piece manner. For example, the optical block can be made of a polyetherimide, such as Ultem™ manufactured by Sabic USA located in Houston, TX. Alternatively, the optical block 78 can be made of other types of polymers, such as cycloolefin copolymers or polycarbonate materials. In yet another alternative, the optical block 78 can be formed from an inorganic material, such as molded glass, e.g., fused silica glass. The alignment features 154 can be formed during the same molding process as the remainder of the optical block 78. An important property of either or both of the type-II alignment features 156 and / or the sidewalls 176 of the mating element 163 is that the type-II alignment features 156 and / or the sidewalls 176 of the mating element 163 can deform under an applied stress without suffering any type of severe failure, such as cracking. For example, if the width W B1 of the wedge 157 at the intersection between the upper section 168 and the lower section 170 is slightly greater than the width W A1 at the top of the recessed area 174 of the recessed area 174, then either or both of the sidewalls 176 of the wedge 157 or the recessed area 174 can deform to allow the support 161 to rest on the mating surface 164. It should be understood that the type-II alignment features 156 and the type-I alignment features 160 can have forms different from those depicted in FIGS. 3 to 9 and described above. For example, the type-II alignment features 156 can be in the form of a rod, a cone, or a truncated cone, which cooperate with a suitably shaped recessed area 174. The type-I alignment features 160 can be a continuous ring or segments of a ring distributed on the bottom surface 152, rather than a discrete number of individual supports 161 distributed on the bottom surface 152 of the optical block 78. The ring or ring segments can be positioned near the edge of the bottom surface 152 such that the contact points between the type-I alignment features 160 are more widely separated. An advantage of the wedge system described above is that it allows materials with different coefficients of thermal expansion (CTEs) to mate with a minimum of mechanical stress introduced into the components. For example, the mating element 163 can be a lens array formed of molded glass having a small coefficient of thermal expansion (CTE) (such as less than 10 ppm / °C). The optical block can utilize the precision molding capabilities of a polymer having a large CTE (such as greater than 50 ppm / °C). The mismatch between the CTE of the optical block 78 and the CTE of the lens array can be greater than 20, 30, 40, 50, or 60 ppm / °C. If the spacing between adjacent wedges 157 is 4 mm and the CTE mismatch is 50 ppm / °C, then the unconstrained optical block 78 and the lens array will have a differential distance change of 0.2 microns / °C. Over a temperature range of 50°C, this will be a differential distance change of 10 microns. By fabricating the optical block 78 from a compliant polymer and arranging the wedges 157 as described above, the wedges 157 can withstand the stresses induced by the CTE mismatch without breaking or cracking. The recessed regions 174 in the mating surface 164 can be formed using a laser writing etching process. The laser writing process can have micron or sub-micron tolerances, and the etching process forming the recessed regions 174 can be sufficiently characterized to achieve a tolerance of less than 1, 2, 3, 4, or 5 microns for the width W of the recessed regions 174 (see FIG. 8). In one specific example, all of the recessed regions 174 can be fabricated to have the same dimensions within the manufacturing tolerances. In an alternative specific example, the width of the recessed regions 174 can be based on the width of the wedges 157 configured to mate with the recessed regions 174. After manufacturing, the wedge width can be accurately measured, for example, within an uncertainty of 1 micron, 2 microns, or 5 microns, and then the width of the mating recessed regions 174 can be adjusted to provide an optimal fit for the wedges 157. The adjustment of the recessed regions 174 can be accomplished by laser writing a pattern in the mating surface 164 to provide an optimal fit for the wedges 157. The wedges 157 can be arranged such that even in the worst case, the wedges 157 never interfere with the recessed regions 174, always have some degree of interference, or a middle arrangement can be selected where the interference varies on a part-by-part basis between the wedges 157 and the recessed regions 174. A1 (see FIG. 8). In one specific example, all of the recessed regions 174 can be fabricated to have the same dimensions within the manufacturing tolerances. In an alternative specific example, the width of the recessed regions 174 can be based on the width of the wedges 157 configured to mate with the recessed regions 174. After manufacturing, the wedge width can be accurately measured, for example, within an uncertainty of 1 micron, 2 microns, or 5 microns, and then the width of the mating recessed regions 174 can be adjusted to provide an optimal fit for the wedges 157. The adjustment of the recessed regions 174 can be accomplished by laser writing a pattern in the mating surface 164 to provide an optimal fit for the wedges 157. The wedges 157 can be arranged such that even in the worst case, the wedges 157 never interfere with the recessed regions 174, always have some degree of interference, or a middle arrangement can be selected where the interference varies on a part-by-part basis between the wedges 157 and the recessed regions 174. The advantage of having the wedged optical block 287 and the mating element 163 formed of two different materials is that when interference occurs between the two, one material can yield relatively easily. Since the amount of interference is small and the yield stress in one part (the optical block 278 formed of a polymer) is so low, the forces generated in the type-II alignment feature 156 can be extremely small and easily overcome during assembly and operation over a large temperature range. As described above, the contact surface of the type-II alignment feature 156, i.e., the sidewall of the wedge 157, can be designed to contact along the edge rather than over a larger planar area. This helps to concentrate the forces generated when interference occurs between the wedge 157 and the recessed area 174, such that the stress induced in the wedge 157 will more readily exceed the yield stress of the material forming the wedge 157. The resulting deformation and stress are local and do not threaten the overall mechanical stability of the wedge 157, just as a drilled hole in a wooden tabletop does not endanger splitting the table in half. Any material displacement (i.e., strain) occurring in the wedge 157 can be extremely small and localized, such that the stress in most of the wedge 157 and the optical block 287 is reduced / relieved to near zero. In other words, the stress does not extend beyond the interference zone to affect the overall feature stability. An advantage of the optical system described above is that light can be collimated at the optical interface 181 between the wedged optical block 278 and the mating element 163. A light beam can be considered collimated in the region along its propagation path within the Rayleigh length of the beam waist. Thus, the optical interface 181 is located within the Rayleigh length of the beam waist of the light beam propagating through the wedged optical block 278. As described above, the optical interface 181 can be filled with a refractive-index-matching material or a transparent material 167. Having a collimated light beam at the optical interface 181 results in increased lateral and longitudinal alignment tolerances at the optical interface 181, while strict control of tilt is required, which is achieved by the support 161. It should be understood that although specific examples of the present invention have been described as including the wedge 157 on the optical block 278 and the recessed area 174 in the mating surface 164, the arrangement can be reversed, and the wedge can be formed in the mating surface while the recessed area can be formed in the optical block 287. Another alternative would be to form some wedges 157 on the optical block 278 and some wedges 157 on the mating surface 164, with corresponding recessed areas 174 on the opposing surfaces. FIG. 10 shows a cross-sectional view of the optical interconnect 50 using the first configuration according to a specific example of the present disclosure. Components present in the cross-sectional plane are shown as solid objects, and components outside the plane are shown as lines. The first configuration may correspond to an optical interconnect module configured to operate in a benign environment and may include an exposed optical path. The cross-sectional view is in a plane parallel to the X-Z plane. The cable sleeve 23 may support a plurality of optical fibers 114, which include end faces 115 located at the front face 87 of the cable sleeve 23. The front face 87 may be substantially planar and oriented parallel to the Y-Z plane. The end face 115 may protrude slightly, such as by several micrometers, from the plane formed by the remainder of the front face 87. For the first configuration optical interconnect 50, the front face 87 of the cable sleeve 23 abuts the cable contact surface 122 of the optical block 78. The contact between the cable contact surface 122 and the front face 87 may be located between the outer portion 140 of the front face 87 of the cable sleeve 23 (see FIG. 2) and the outer surface 146 of the cable contact surface 122 (see FIG. 3). As previously described, the cable contact surface 122 may include a recessed region 132 that includes a protruding portion 130 and an inner surface 144. The recessed region 132 may be filled with a gas having a refractive index approximately equal to one. A plurality of cable-facing lenses 112 may be located on the inner surface 144 of the cable contact surface 122. Adjacent the cable contact surface 112 to the front face 87 positions the front face 87 at a distance d from the inner surface 144 1 . The distance d 1 may be selected such that light propagating from the end face 115 of the optical fiber 114 can be substantially collimated by the plurality of cable-facing lenses 112. The same distance d 1 will also cause the collimated light propagating from the plurality of cable-facing lenses 112 to be focused on the end face 115 of the optical fiber 114. The propagating light may follow an optical path aligned parallel to the X direction in the region between the reflective surface 120 and the inner surface 144. The optical block 78 may also include a reflective surface 120 and a photoelectric element contact surface 124. If the optical block 78 is part of a transmitter, collimated light may follow an optical path from the photoelectric element contact surface 124 to the reflective surface 120 and from there to one of the lenses 112 facing the cable. The light may be focused by the lens 112 facing the cable onto the end face 115 of the optical fiber 114. If the optical block 78 is part of a receiver, light may follow an optical path from the end face 115 of the optical fiber 114 to the lens 112 facing the cable. The lens 112 facing the cable may collimate the light. The collimated light may then follow an optical path from the lens 112 facing the cable to the reflective surface 120 and from there to the photoelectric element contact surface 124. If the optical block 78 is part of a transceiver, some of the lenses 112 facing the cable transfer light from the photoelectric element contact surface 124 to the optical fiber 114, and then some of the lenses 112 facing the cable transfer light from the optical fiber 114 to the photoelectric element contact surface 124. The photoelectric element contact surface 124 may include a bottom socket 180 that includes an inner surface 184 configured to allow an optical signal to pass through. The inner surface 184 through which the light transfer of the photoelectric element contact surface 124 passes may be substantially planar and have no optical power. The photoelectric element contact surface 124 may include one or more alignment features (not shown in FIG. 9) configured to positively engage corresponding alignment features on a mating component. Any suitable alignment may be used as an alignment feature. The reflective surface 120 may be substantially planar and have no optical power. Alternatively, optical power may be incorporated into the reflective surface 120 by using an off-axis paraboloidal reflector in each optical path through the optical block 78. If the reflective surface 120 has optical power, the lens 112 facing the cable may be eliminated, and the inner surface 144 of the cable contact surface may have no optical power. The reflective surface 120 may be a total internal reflection (TIR) surface that redirects light by substantially 90 degrees. Alternatively, the reflective surface 120 may include an optical coating, such as a metal coating, or may redirect the optical path at an angle different from 90 degrees. In many cases, it may be desirable to attenuate one or more optical signals propagating through the optical block 78. In some cases, the optical block 78 may only provide a controlled degree of attenuation for the transmitted signal and not for the received signal. In other cases, attenuation may be provided for both the transmitted signal and the received signal. Here, the term providing a controlled degree of attenuation means that in addition to any inherent attenuation present in any material or surface, some additional attenuation features are also added or included in the optical block 78. Attenuation can be provided by intentionally introducing defects into the reflective surface 120, such as by laser texturing the reflective surface 120. The use of intentionally adding a controlled degree of attenuation on the reflective surface is described in U.S. Patent No. 10,884,198, which is assigned to the same assignee as the present application. Other methods can be used to introduce attenuation, including adding an absorbing element somewhere in the optical path and adding an absorbing or scattering material to the body of the optical block 78. Attenuation can also be added by texturing surfaces other than the reflective surface 120 in the optical path. If the reflective surface 120 is optically coated, it can also be textured to provide attenuation. For example, a metallized surface can be textured as described in PCT Patent Application Publication No. WO 2022 / 216705, which is assigned to the same assignee as the present application. Returning to FIG. 10, three rows of cable-facing lenses 112 are shown in the figure; however, as shown in FIG. 2, there may be only two rows of optical fibers 114 in the cable sleeve 23. In the specific example depicted in FIG. 10, the center row of the cable-facing lenses 112 is not used. The advantage of including the unused cable-facing lenses 112 on the optical block 78 is that it enables the optical block 78 to be used with cable sleeves that include both single rows of optical fibers 114 and two rows of optical fibers. Another advantage of including the additional cable-facing lenses 112 is that a regular dense lens array can improve uniformity relative to lenses with a wider spacing. More than three rows of cable-facing lenses 112 can be located on the optical block 78, such as four rows, five rows, or six rows. There may be unused cable-facing lenses 112 at the ends of each row of cable-facing lenses 112. The optical interconnect 50 depicted in FIG. 10 can be used in many applications; however, it may not be suitable for use in harsh environments where the interconnect can be exposed to contamination from the surrounding environment. Different types of optical interconnects can be used for such applications, where the optical path is sealed from the external environment. As described below, this robust optical interconnect can be made using the same optical block 78 and cable sleeve 23. Advantageously, using common parts for the two types of optical interconnects reduces cost and improves manufacturability. For performing a more robust optical interconnection including a sealed optical path, various components may be attached to the optical block 78 to form an optical block subassembly. FIG. 11 shows an exploded view of an optical block subassembly 70 including the optical block 78, a transparent plate 126, and a reflective surface cover 136. Before installing the optical block 78 in the optical interconnection module, the transparent plate 126 and the reflective surface cover 136 may be attached to the optical block 78. The optical block 78 may include one or more reference features configured to align with corresponding reference features 142 (see FIG. 2) of the cable sleeve 23. The reference features in the optical block 78 are two guide pins 80 protruding from the cable contact surface 122. The transparent plate 126 may be positioned between the two guide pins 80 and attached to the protruding portion 130 of the cable contact surface 122. The transparent plate 126 may cover all the inner surfaces 144 of the cable contact surface 122 such that no external contaminants can reach the inner surfaces 144, where the external contaminants may interfere with the optical path passing through the inner surfaces 144. The optical block 78 may also include a reflective surface 120. The reflective surface cover 136 may be attached to the optical block 78 such that the reflective surface cover 136 is spaced apart from and covers the reflective surface 120, thereby preventing any external contaminants from contacting the reflective surface 120 and changing its reflective properties. In some embodiments, the reflective surface cover 136 may be transparent such that laser texturing of the reflective surface 120 may be performed after the reflective surface cover 136 has been installed on the optical block 78. It should be understood that the optical block 78 depicted in FIG. 10 is the same as the optical block 78 previously described and used in the first configuration. Figure 12 shows a cross-sectional view of an optical block 78 having a transparent plate 126 and a reflective surface cover 136 attached to the optical block 78 according to a specific example of the present disclosure. Elements present in the cross-sectional plane are shown as solid objects, and elements out of the plane are shown as lines. The transparent plate 126 can be attached to the cable contact surface 122 along the protruding portion 130. The protruding portion 130 can be attached to a portion of the first surface 148 of the transparent plate 126 positioned around the perimeter of the first surface 148. The attachment of the transparent plate 126 to the protruding portion 130 can form a cable-facing lens region 133 adjacent to the inner surface 144 of the cable contact surface 122. An adhesive or epoxy can be used to attach the transparent plate 126 to the protruding portion 130. The adhesive or epoxy can form a seal that isolates the enclosed region 133 from the surrounding environment, thereby preventing contamination of any surface within the enclosed region 133. A gas such as dry nitrogen, dry air, or some other gas can be contained within the enclosed region 133. The inner surface 144 can include one or more cable-facing lenses 112 included in the lens array. The cable-facing lens 122 can be used to focus or collimate a plurality of light beams traversing the lens array. The transparent plate 126 can include a second surface 150 opposite the first surface 148. Both the first surface 148 and the second surface 150 can be located in a plane substantially parallel to the Y-Z plane. The second surface 150 of the transparent plate 126 can extend beyond the outer surface 146 of the cable contact surface 122 in the longitudinal or X direction. The guide pins 80 of the optical block 78 extend beyond the transparent plate 126 such that the ends of the guide pins 80 can still engage with a cable sleeve (not shown in FIG. 12). Figure 13 shows an exploded perspective view of a detachable cable assembly 15 and a refractive index matching film 134 according to a specific example of the present disclosure. As previously described, one end of the detachable cable assembly 15 can be terminated in a cable sleeve 23. The refractive index matching film 134 can be attached to the front face 87 of the cable sleeve 23. The refractive index matching film 134 can be thin, such as having a thickness of less than approximately 50 microns, and can be adhered to the front face 87. The refractive index matching film 134 can be thicker than 50 microns, for example, greater than 50 microns and less than 100, 150, or 200 microns. The refractive index matching film 134 can be alleged to seal a plurality of optical fiber end faces 115 located on the front face 87. Figure 14 shows a cross-sectional view of the optical interconnect 60 using the second configuration according to a specific example of the present disclosure. The second configuration 60 of the optical interconnect is suitable for operation in a contaminated environment and includes a sealed optical path isolated from the external environment. The components present in the cross-sectional plane are shown as solid objects, and the components outside the plane are shown as lines. The second configuration includes a sealed optical path. The transparent plate 126 seals the lens 112 facing the cable, and the refractive index matching film 134 seals the interface between the second surface 150 of the transparent plate and the front surface 87 of the cable sleeve 23. Advantageously, the optical block 78 can be the same as the optical block 78 used in the first configuration and depicted in FIG. 9. This helps to achieve economies of scale by allowing common optical blocks to be used in both benign and harsh environment applications. Compared with the first configuration shown in FIG. 10, when the cable sleeve 23 mates with the optical block 78 in the second configuration, the front surface 87 of the cable sleeve 23 does not contact the optical block 78. Instead, the inner portion 138 of the front surface 87 of the cable sleeve 23 contacts the transparent plate 126. The transparent plate 126 abuts the protruding portion 130 on the surface opposite to the surface contacting the front surface 87 of the cable sleeve 23. The distance d from the first configuration 1 In comparison, this increases the distance d between the inner surface 144 of the cable contact surface 122 and the front surface 87 of the cable sleeve 23 2 . The distance d 2 can be controlled by the thickness t of the transparent plate 126. The optical path length can be defined as the length of the optical path multiplied by the refractive index of the optical path. The distance d 2 can be selected such that the optical path length between the inner surface 144 containing the lens 112 facing the cable and the front surface 87 of the optical cable 23 is equal to the optical path length between the lens 112 facing the cable and the front surface 87 in the first configuration. Therefore, the optical path length of the second configuration can be substantially equal to d 1 . In other words, the first optical path length between the inner surface 144 and the outer surface 146 of the cable contact surface 122 is equal to or substantially equal to the second optical path length between the inner surface 144 of the cable contact surface 122 and the second surface 150 of the transparent plate 126. Here, substantially equal means that the two optical path lengths are within ±1%, ±5%, ±10%, or ±20% of each other. For example, assume that the depth of the recessed area 132 between the outer surface 146 and the inner surface 144 is 2 mm. Since in the first configuration, the front surface 87 of the cable sleeve 23 abuts the outer surface 146 of the cable contact surface 122 of the optical block 78, the distance d 1 is equal to 2 mm. Since the recessed area 132 can have a refractive index close to one, the optical path length is 2 mm. Further assume that the protruding portion 130 is 1 mm away from the inner surface 144, and both the transparent plate 126 and the refractive index matching film 134 have a refractive index equal to approximately 1.5. In order to have an equal optical path length in both configurations, the transparent plate 126 and the refractive index matching film 134 must have a combined thickness of 1.5 mm. In the second configuration shown in FIG. 8, the optical path includes two segments: a first segment that traverses air or some other gas having a refractive index substantially equal to one; and a second segment that traverses the transparent plate and the refractive index matching film. Thus, the optical path length of the second configuration is 1 mm plus 1.5 mm / 1.5 or 2 mm, equal to the path length of the first configuration. Since the thickness of the refractive index matching film 134 can be extremely small compared to the thickness of the transparent plate 126, the contribution of the refractive index matching film 134 to the total optical path length can be small compared to the contribution of the transparent plate 126 to the total optical path length. In the first configuration, it can be claimed that the optical block 78 is configured to directly receive the cable sleeve 23 because when the cable sleeve is mated with the optical interconnect module 10, the front face 87 of the cable sleeve 23 is directly adjacent to the optical block 78. Here, directly adjacent means that the front face 87 of the optical block 78 contacts the optical block 78 or is spaced apart from the optical block 78 by a thin refractive index matching film. In the second configuration, it can be claimed that the optical block 78 is configured to indirectly receive the cable sleeve 23 because the transparent plate 126 is located between the front face 87 of the cable sleeve 23 and the optical block 78, and the front face 87 of the cable sleeve is directly adjacent to the second face 150 of the transparent plate 126 when the cable sleeve 23 is mated with the optical interconnect module 10. Thus, the cable sleeve 23 is indirectly received by the optical block 78 because there is an intervening transparent plate 126 in the second configuration. As described above, the optical design of the optical interconnect module 10 achieves effective optical coupling between the optical fiber 114 and the optoelectronic element in both the first and second configurations. Effective optical coupling is achieved by making the optical path lengths of both the first and second configurations the same within manufacturing tolerances. The manufacturing tolerances can be within 1%, 2%, 5%, or 10%. In both the first and second configurations, the detachable cable assembly 15 can be removed from the interconnect module 10 by raising the cable latch 29 and moving the detachable cable assembly 15 away from the interconnect module 10 along the X direction (see FIG. 1). Generally, it can be claimed that the optical block 87 includes alignment features that facilitate the establishment of optical communication between the optoelectronic element and the optical fiber. The optical fiber can be part of a detachable cable assembly configured to mate and unmate with the optical block. Either the first or second optical interconnect configuration can use a wedged or non-wedged optical block. Terms such as "top", "bottom", "upper", "above", "below", "upper part", and "lower part" are relative terms based on the coordinate system depicted in FIG. 1, which shows a Z-axis pointing in an upward or vertical direction. The optical interconnect module 10 can be used in any orientation. It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of the applicable method. Depending on design preferences, the specific order or hierarchy of steps in the process can be rearranged while remaining within the scope of this disclosure. The accompanying method claims present the elements of the various steps in a sample order and are not meant to be limited to the specific order or hierarchy presented. It should be understood that the foregoing description merely illustrates the invention. Various alternatives and modifications can be designed by those of ordinary skill in the art without departing from the invention. For example, the placement of the wedge and the recessed area can be reversed, rather than including an optical block with a wedge and a mating element including a recessed area configured to accommodate the wedge. That is, the optical block can include a plurality of recessed areas, and the mating element can include a plurality of wedges. Similarly, the support is described as being located on the optical block, but the support can be located on the mating element. Accordingly, the invention is intended to cover all such alternatives, modifications, and variations that fall within the scope of the appended claims. In addition, in some specific examples, an optical block can include a cable contact surface configured to directly receive a cable ferrule in a first configuration and indirectly receive the cable ferrule in a second configuration. In various specific examples, the cable contact surface can include: a recessed area located within the outer surface of the cable contact surface; and a protruding portion located within the recessed area. In various specific examples, the recessed area can include an inner surface surrounded by the protruding portion. In some specific examples, a plurality of lenses facing the cable can be located on the inner surface. In some specific examples, in the first configuration, when the cable ferrule mates with the optical block, the front face of the cable ferrule can be directly adjacent to the optical block. In some specific examples, when the cable ferrule mates with the optical interconnect module, the front face of the cable ferrule can be directly adjacent to the outer surface of the cable contact surface. In some specific examples, in the second configuration, when the cable ferrule mates with the optical block, the front face of the cable ferrule can be directly adjacent to the second face of the transparent plate. In various specific examples, the first face of the transparent plate opposite the second face of the transparent plate can abut the protruding portion in the recessed area of the cable contact surface. In some specific examples, the cable ferrule can be an MT-type ferrule. In addition, in some specific examples, an optical component may include a cable contact surface that includes a recessed area. The recessed area may be located within the outer surface of the cable contact surface. The optical component may also include an inner surface and a protruding portion. The inner surface and the protruding portion may be located within the recessed area. In various specific examples, the optical component may also include at least one lens facing the cable on the inner surface of the recessed area. In some specific examples, the at least one lens facing the cable may be a plurality of lenses facing the cable. In some specific examples, the plurality of lenses facing the cable may be arranged in at least one row. In some specific examples, the plurality of lenses facing the cable may be arranged in two rows, each row including a plurality of lenses. In some specific examples, the protruding portion may be a continuous protruding portion surrounding the inner surface of the recessed area. In some specific examples, the optical component may include a optoelectronic element contact surface and a reflective surface. In some specific examples, the optoelectronic element contact surface may include a second recessed area that includes an inner surface of the second recessed area. In some specific examples, the inner surface of the second recessed area may be planar. In some specific examples, the optoelectronic element contact surface may include one or more alignment features configured to positively engage corresponding alignment features on a mating component. In some specific examples, the optical component may be configured to provide a controlled degree of attenuation to an optical signal propagating through the optical component. In some specific examples, the optical component may be a part of an optical component sub-assembly that includes the optical component and a transparent plate attached to the protruding portion of the optical component. In some specific examples, the first surface of the transparent plate may be attached to the protruding portion, and the second surface of the transparent plate may be located in a plane parallel to the inner surface. In some specific examples, the second surface of the transparent plate may extend longitudinally beyond the outer surface of the cable contact surface. In some specific examples, the first optical path length between the inner surface and the outer surface of the cable contact surface may be substantially equal to the second optical path length between the inner surface of the recessed area and the second surface of the transparent plate. In some specific examples, the optical component sub-assembly may include a reflective surface cover. Additionally, in some specific examples, an optical block may include a cable contact surface configured to receive a detachable cable assembly. In some specific examples, the optical block may further include a photoelectric element contact surface that includes a plurality of alignment features. In some specific examples, the plurality of alignment features may be configured to passively align the optical block relative to a mating surface in six degrees of freedom. In some specific examples, the plurality of alignment features may include at least one type-I alignment feature that facilitates passive alignment of the optical block relative to the mating surface in a lateral direction, a longitudinal orientation, and a lateral rotation orientation. In some specific examples, the at least one type-I alignment feature may be at least three type-I alignment features. In some specific examples, the at least three type-I alignment features may be four type-I alignment features. In some specific examples, each of the type-I alignment features may be a pedestal. In various specific examples, each of the type-I alignment features may be located near an edge of the photoelectric element contact surface. In some specific examples, the plurality of alignment features may include at least one type-II alignment feature that facilitates passive alignment of the optical block relative to the mating surface in a longitudinal direction, a lateral direction, and a lateral rotation orientation. In some specific examples, the at least one type-II alignment feature may be at least two type-II alignment features. In some specific examples, the at least two type-II alignment features may include a longitudinally extending wedge and a laterally extending wedge. In some specific examples, the at least two type-II alignment features may include a longitudinally extending wedge and two laterally extending wedges. In some specific examples, the cross-sectional shapes of the longitudinally extending wedge and the laterally extending wedge may be the same. In some specific examples, the cross-sectional shape may be symmetric about a bisecting plane. In some specific examples, both the longitudinally extending and the laterally extending wedges may include two wedge sidewalls, and each wedge sidewall may include an upper section and a lower section. In some specific examples, the orientation angle of the upper section may be less than the orientation angle of the lower section. In some specific examples, the longitudinally extending wedge may extend a greater distance in the longitudinal direction than the laterally extending wedge extends in the lateral direction. In some specific examples, the optical block may further include a substantially planar reflective surface that does not have optical power. In some specific examples, the cable contact surface may be configured to mate with a detachable cable assembly. In some specific examples, the number of type-I alignment features may be different from the number of type-II alignment features. Additionally, in some specific examples, an optical component may include a cable contact surface that includes a recessed area. In various specific examples, the cable contact surface may be configured to accommodate a cable sleeve, and the recessed area may be located within the outer surface of the cable contact surface. In some specific examples, the optical component may further include an inner surface and a protruding portion. In some specific examples, the inner surface and the protruding portion may be located within the recessed area. In some specific examples, the optical component may further include a optoelectronic element contact surface that includes a plurality of alignment features. In some specific examples, the plurality of alignment features may be configured to passively align the optical component against a mating surface with respect to six degrees of freedom. In some specific examples, at least one cable-facing lens may be located on the inner surface of the recessed area. In some specific examples, the at least one cable-facing lens may be a plurality of cable-facing lenses. In some specific examples, the plurality of cable-facing lenses may be arranged in at least one row. In some specific examples, the plurality of cable-facing lenses may be arranged in two rows, each row including a plurality of cable-facing lenses. In some specific examples, the protruding portion may be a continuous protruding portion surrounding the inner surface of the recessed area. In some specific examples, the optical component may further include an optoelectronic element contact surface and a reflective surface. In some specific examples, the optoelectronic element contact surface may include a second recessed area that includes an inner surface of the second recessed area. In some specific examples, the inner surface of the second recessed area may be planar. In some specific examples, the optoelectronic element contact surface may include one or more alignment features that are configured to actively engage corresponding alignment features on a mating element. In some specific examples, the optical component may be configured to provide a controlled degree of attenuation to an optical signal propagating through the optical component. In some specific examples, the optical component may be a part of an optical component subassembly that includes the optical component and a transparent plate attached to the protruding portion. In some specific examples, the first surface of the transparent plate may be attached to the protruding portion, and the second surface of the transparent plate may be located in a plane parallel to the inner surface. In some specific examples, the second surface of the transparent plate may extend longitudinally beyond the outer surface of the cable contact surface. In some specific examples, a first optical path length between the inner surface of the recessed area and the outer surface of the cable contact surface may be substantially equal to a second optical path length between the inner surface of the recessed area and the second surface of the transparent plate. In some specific examples, the optical component subassembly may include a reflective surface cover. Additionally, in some specific examples, an optical interconnection may include: an optical block including: a recessed area located within a cable contact surface; and a protruding portion located within the recessed area; and a cable sleeve including a front face configured to mate with the optical block in a first configuration of the optical interconnection between the optical block and the cable sleeve. The optical interconnection may include a second configuration, and the second configuration is different from the first configuration. In some specific examples, the protruding portion may be a continuous protruding portion surrounding an inner surface of the recessed area. In some specific examples, at least one cable-facing lens may be formed on the inner surface of the recessed area. In some specific examples, at least one cable-facing lens may be a plurality of cable-facing lenses. In some specific examples, at least one of the plurality of cable-facing lenses may not be used in the optical interconnection. In some specific examples, the plurality of cable-facing lenses may be arranged in at least one row. In some specific examples, the plurality of cable-facing lenses may be arranged in three rows, each row including a plurality of cable-facing lenses. In some specific examples, only two rows of the plurality of cable-facing lenses may be used in the optical interconnection. In some specific examples, only one row of the plurality of cable-facing lenses may be used in the optical interconnection. In some specific examples, in the first configuration, the front face of the cable sleeve may contact an outer surface of the cable contact surface of the optical block. In some specific examples, an outer portion of the front face of the cable sleeve may contact the cable contact surface, and an inner portion of the front face may not contact the cable contact surface. In some specific examples, the second configuration may further include a transparent plate located between the inner surface of the recessed area and the front face of the cable sleeve. In some specific examples, a portion of a first face of the transparent plate may contact the protruding portion. In some specific examples, a second face of the transparent plate may contact the front face of the cable sleeve. In some specific examples, an inner portion of the front face of the cable sleeve may contact the transparent plate, and an outer portion of the front face may not contact the transparent plate. In some specific examples, the transparent plate may form a seal against the protruding portion to define a closed cable-facing lens area that environmentally isolates the cable-facing lenses from the surrounding environment. In some specific examples, the front face of the cable sleeve may contain at least one end face of an optical fiber. In some specific examples, at least one end face of the optical fiber may be a plurality of optical fiber end faces. In some specific examples, the plurality of optical fiber end faces may be arranged in two rows. In some specific examples, the plurality of optical fiber end faces may be arranged in one row. In some specific examples, the cable sleeve may be an MT-type sleeve. In some specific examples, a common optical interconnection module is used in both the first configuration and the second configuration. In some specific examples, the first configuration may include an exposed optical path. In some specific examples, the second configuration may include a sealed optical path. Additionally, in some specific examples, an optical interface may include: a photoelectric element contact surface of a wedge-shaped optical block, the photoelectric element contact surface including at least one type-I alignment feature extending from the photoelectric element contact surface and a plurality of type-II alignment features extending from the photoelectric element contact surface; and a mating surface of a mating element, the mating surface including a plurality of recessed areas in the mating surface, wherein the plurality of type-II alignment features are inserted into the plurality of recessed areas, and at least one type-I alignment feature contacts the mating surface, thereby passively aligning the wedge-shaped optical block with the mating element. In some specific examples, a plurality of collimated light beams may pass through the optical interface. In some specific examples, at least one type-I alignment feature helps to passively align the optical block relative to the mating surface in the lateral direction, longitudinal orientation, and lateral rotation orientation. In some specific examples, the plurality of type-I alignment features may be at least three supports. In some specific examples, the plurality of type-II alignment features may passively align the wedge-shaped optical block relative to the mating surface in the longitudinal direction, lateral direction, and lateral rotation orientation. In some specific examples, the plurality of type-II alignment features may be a plurality of wedges. In some specific examples, the plurality of wedges may be three wedges. In some specific examples, the three wedges may include a longitudinally extending wedge and two laterally extending wedges. In some specific examples, the two laterally extending wedges may be arranged along a laterally extending bisector. In some specific examples, the longitudinally extending wedge may be arranged along a longitudinally extending bisector. In some specific examples, the longitudinally extending bisector and the laterally extending bisector may intersect at a virtual center. In some specific examples, the plurality of collimated light beams may be symmetrically arranged about the virtual center. In some specific examples, the longitudinally extending wedge may be longer than the two laterally extending wedges. In some specific examples, the plurality of wedges may be asymmetrically arranged relative to the laterally extending bisector. In some specific examples, at least one of the plurality of type-II alignment features includes deformation caused by the recessed area into which it is inserted. In some specific examples, the deformation may be localized to a part of the sidewall of at least one of the plurality of type-II alignment features. In some specific examples, the mating element may be a lens array. In addition, in some specific examples, a passive alignment optical interconnect system may include: an optical component including a photoelectric element contact surface having a plurality of optical component alignment features; and a mating component that may include a plurality of mating component alignment features configured to mate with the plurality of optical component alignment features such that when the plurality of optical component alignment features mate with the plurality of mating component alignment features, the optical component is passively aligned with the mating component in six degrees of freedom. In some specific examples, the mating component may be a lens array. In some specific examples, the mating component may include a substantially planar top surface. In some specific examples, the substantially planar top surface may include a plurality of recessed areas defining the mating component alignment features. In some specific examples, the plurality of optical component alignment features may include a plurality of wedges and a plurality of pedestals. In some specific examples, the height of each of the plurality of pedestals is equal. In some specific examples, the plurality of wedges may include longitudinally extending wedges and laterally extending wedges. In some specific examples, the cross-sectional shapes of the longitudinally extending wedges and the laterally extending wedges may be the same. In some specific examples, the cross-sectional shape may be symmetric about a bisecting plane. In some specific examples, both the longitudinally extending and laterally extending wedges may include wedge sidewalls, and the wedge sidewalls may include an upper section and a lower section. In some specific examples, the orientation angle of the upper section may be less than the orientation angle of the lower section. In some specific examples, the longitudinally extending wedge may extend a greater distance in the longitudinal direction than the laterally extending wedge extends in the lateral direction. In some specific examples, the depth of each of the plurality of recessed areas may be greater than the difference between the height of each of the plurality of wedges and the height of the plurality of pedestals such that when the plurality of wedges mate with the plurality of recessed areas, the plurality of wedges do not bottom out. In some specific examples, the width at the top of each of the plurality of recessed areas is equal to or approximately equal to the width of the plurality of wedges at the height of the plurality of pedestals within manufacturing tolerances. In some specific examples, the orientation angle of the upper section may be greater than the orientation angle of the sidewalls of the plurality of recessed areas. In some specific examples, the optical component includes a substantially planar reflective surface having no optical power. In some specific examples, the cable contact surface may be configured to mate with a detachable cable assembly. In addition, in some specific examples, a method for optical interconnection between a cable sleeve and an optical interconnection module is disclosed. The optical interconnection may include a first configuration in which the front face of the cable sleeve contacts an outer portion of the cable contact surface of the optical block, and may include a second configuration in which the front face of the cable sleeve contacts a transparent plate located between the optical block and the cable sleeve. In some specific examples, in the first configuration, the outer surface of the front face of the cable sleeve may contact the optical block, and the inner surface of the front face of the cable sleeve may not contact the optical block. In some specific examples, in the second configuration, the inner surface of the front face of the cable sleeve contacts the transparent plate, and the outer portion of the front face of the cable sleeve does not contact the optical block. In some specific examples, the cable sleeve may be fastened to the optical interconnection module using a swing latch engaged with the back face of the cable sleeve. It should be understood that the foregoing description merely illustrates the present invention. Various alternatives and modifications can be designed by those of ordinary skill in the art without departing from the present invention. Therefore, the present invention is intended to cover all such alternatives, modifications, and variations that fall within the scope of the appended claims. 10: Optical Interconnection Module 15: Detachable Cable Assembly 22: Cable 23: Cable Sleeve 29: Cable Latch 35: Pivot Axis 50: First Configuration of Optical Interconnection 52: Module Frame 60: Second Configuration of Optical Interconnection 70: Optical Block Sub - assembly 78: Optical Block 80: Guide Pin 87: Front of Cable Sleeve 89: Back of Cable Sleeve 90: Tilted Surface 92: Cable Latch Edge 112: Lens Facing Cable 114: Optical Fiber 115: End Face of Optical Fiber 120: Reflective Surface 122: Cable Contact Surface of Optical Block 124: Optoelectronic Element Contact Surface 126: Transparent Plate 130: Protruding Portion or Intermediate Surface 132: Recessed Area 133: Enclosed Area 134: Refractive Index Matching Film 136: Reflective Surface Cover 138: Inner Portion of the Front of Cable Sleeve 140: Outer Portion of the Front of Cable Sleeve 142: Reference Feature (Precision Hole) 144: Inner Surface of Cable Contact Surface 146: Outer Surface of Cable Contact Surface 148: First Side of Transparent Plate 150: Second Side of Transparent Plate 152: Bottom Surface of Optical Block 154: Alignment Feature on Optical Block 156: Type - II Alignment Feature 157: Wedge 158: Laterally Extended Wedge 159: Side Wall of Wedge 160: Type - I Alignment Feature 161: Support 162: Longitudinally Extended Wedge 163: Fitting Element 164: Fitting Surface 165: Gap 166: Equivalent Plane 167: Transparent Adhesive 168: Upper Section of Side Wall 159 170: Lower Section of Side Wall 159 171: Laterally Extended Equivalent Line 172: Bottom Surface of Support 173: Longitudinally Extended Equivalent Line 174: Recessed Area 175: Virtual Center 176: Side Wall of Recessed Area 177: Optical Path 178: Wedge - less Optical Block 180: Bottom Socket 181: Optical Interface 182: Fitting Direction 184: Inner Surface of Optoelectronic Element Contact Surface 124 278: Wedge - equipped Optical Block d 1 : First Configuration Distance d from the Inner Surface of the Optical Block to the Front of the Cable Sleeve 2 : Second Configuration Distance D from the Inner Surface of the Optical Block to the Front of the Cable Sleeve A : Depth D of the Recessed Area 174 in the Z - direction B : Wedge Height D S : Distance from the Bottom of the Support to the Bottom Surface of the Wedge - equipped Optical Block / Support Height t: Thickness W A1 : Width W at the Top of the Recessed Area A2 : Width W at the bottom of the recessed area B1 : Width W of the wedge at the intersection of the upper and lower sections B2 : Wedge width X at the support height: Direction / Axis Y: Direction / Axis Z: Direction / Axis α a : Orientation angle α of the upper section of the wedge b : Orientation angle γ of the side wall of the recessed area x : Longitudinal rotation γ y : Lateral rotation γ z : Transverse rotation [Figure 1] shows an optical interconnection module and a detachable cable assembly according to a specific example of the present disclosure. [Figure 2] shows a plan view of the front of a cable sleeve according to a specific example of the present disclosure. [Figure 3] shows a plan view of the cable contact surface of an optical block according to a specific example of the present disclosure. [Figure 4] shows a perspective view of the bottom surface of the optical block shown in Figure 3 according to a specific example of the present disclosure. [Figure 5] shows a plan view of the cable contact surface of an optical block according to a specific example of the present disclosure. [Figure 6] shows a perspective view of the bottom surface of the optical block shown in Figure 5 according to a specific example of the present disclosure. [Figure 7] shows a plan view of the optoelectronic element contact surface of a wedge-shaped optical block according to a specific example of the present disclosure. [Figure 8] shows a cross-sectional view of a part of an optical block located above a mating surface according to a specific example of the present disclosure. [Figure 9] depicts the wedge of an optical block inserted into the recessed area of a mating surface according to a specific example of the present disclosure. [Figure 10] shows a cross-sectional view of an optical interconnection using a first configuration according to a specific example of the present disclosure. [Figure 11] shows an exploded perspective view of an optical block sub-assembly according to a specific example of the present disclosure. [Figure 12] shows a cross-sectional view of an optical block sub-assembly according to a specific example of the present disclosure. [Figure 13] shows an exploded view of a detachable cable assembly and a refractive index matching film according to a specific example of the present disclosure. [Figure 14] shows a cross-sectional view of an optical interconnection using a second configuration according to a specific example of the present disclosure. Like reference numerals and designations in the various figures indicate like elements. 78: Optical block 152: Bottom surface of the optical block 154: Alignment feature on the optical block 156: Type-II alignment feature 157: Wedge 158: Lateral extension wedge 160: Type-I alignment feature 161: Support 162: Longitudinal extension wedge 278: Wedge optical block X: Direction / Axis Y: Direction / Axis Z: Direction / Axis γ x : Longitudinal rotation γ y : Lateral rotation γ z : Transverse rotation

Claims

1. An optical block comprising: a cable-facing surface configured to receive a detachable cable assembly; and a photoelectric element contact surface including a plurality of alignment features, wherein the plurality of alignment features are configured to passively align the optical block against a mating surface relative to six degrees of freedom.

2. The optical block of claim 1, wherein the plurality of alignment features includes at least one type I alignment feature that facilitates passive alignment of the optical block relative to the mating surface in the lateral, longitudinal, and lateral rotational orientations.

3. The optical component of claim 2, wherein the at least one type I alignment feature comprises at least three type I alignment features.

4. The optical block of claim 3, wherein the at least three type I alignment features include four type I alignment features.

5. An optical component as claimed in any of claims 2 to 4, wherein each of these Type I alignment features includes a support.

6. An optical block as claimed in any of claims 2 to 4, wherein each of these Type I alignment features is positioned near the edge of the contact surface of the photoelectric element.

7. An optical block as claimed in any one of claims 1 to 4, wherein the plurality of alignment features includes at least one Type II alignment feature that facilitates passive alignment of the optical block relative to the mating surface in the longitudinal, lateral and transverse rotational orientations.

8. The optical block of claim 7, wherein the at least one type II alignment feature comprises at least two type II alignment features.

9. The optical block of claim 8, wherein the at least two Type II alignment features include a longitudinally extending wedge and a laterally extending wedge.

10. The optical block of claim 8, wherein the at least two Type II alignment features include a longitudinally extending wedge and two laterally extending wedges.

11. The optical block of claim 9, wherein the longitudinally extending wedge and the laterally extending wedge have the same cross-sectional shape.

12. The optical block of claim 11, wherein the cross-sectional shape is symmetrical about the bisecting plane.

13. The optical block of claim 9, wherein both the longitudinally extending wedge and the laterally extending wedge include two wedge sidewalls, and each wedge sidewall includes an upper section and a lower section.

14. The optical block of claim 13, wherein the orientation angle of the upper section is smaller than the orientation angle of the lower section.

15. The optical block of claim 9, wherein the longitudinally extending wedge extends a greater distance in the longitudinal direction than the laterally extending wedge extends in the lateral direction.

16. An optical component of any one of claims 1 to 4, further comprising a reflective surface, wherein the reflective surface is substantially planar and has no optical power.

17. An optical block as claimed in any of claims 1 to 4, wherein the cable-facing surface is configured to mate with a detachable cable assembly.

18. The optical component of claim 7, wherein the number of type I alignment features is different from the number of type II alignment features.

19. An optical component comprising: a cable-facing surface including a recessed region, wherein the cable-facing surface is configured to receive a cable sheath, the recessed region being located within an outer surface of the cable-facing surface, and the recessed region including: Internal surface; and the highlighted parts; and the contact surface of the optoelectronic element, which includes a plurality of alignment features, wherein the plurality of alignment features are configured to passively align the optical block with respect to a mating surface with six degrees of freedom.

20. The optical block of claim 19, further comprising at least one cable-facing lens on the inner surface of the recessed area.

21. The optical component of claim 20, wherein the at least one cable-facing lens comprises a plurality of cable-facing lenses.

22. The optical component of claim 21, wherein the plurality of cables-facing lenses are arranged in at least one row.

23. The optical component of claim 22, wherein the plurality of cable-facing lenses are arranged in two rows; and each of the two rows comprises a plurality of cable-facing lenses.

24. An optical block as claimed in any of claims 19 to 23, wherein the protrusion includes a continuous protrusion surrounding the inner surface of the recessed area.

25. The optical component of any one of claims 19 to 23 further includes a photoelectric element contact surface and a reflective surface.

26. The optical component of claim 25, wherein the photoelectric element contact surface includes a second recessed area, the second recessed area including an inner surface of the second recessed area.

27. The optical block of claim 26, wherein the inner surface of the second recessed area is planar.

28. The optical block of claim 25, wherein the contact surface of the photoelectric element includes one or more alignment features configured to actively engage with corresponding alignment features on a mating element.

29. An optical element of any one of claims 19 to 23, wherein the optical element is configured to provide a controlled degree of attenuation for optical signals propagating through the optical element.

30. An optical block subassembly comprising: an optical block as claimed in any one of claims 19 to 29; and a transparent plate attached to the protrusion.

31. The optical block subassembly of claim 30, wherein a first surface of the transparent plate is attached to the protrusion, and a second surface of the transparent plate lies in a plane parallel to the inner surface.

32. The optical block subassembly of claim 31, wherein the second side of the transparent plate extends in the longitudinal direction beyond the outer surface of the side facing the cable.

33. The optical block subassembly of claim 31, wherein the optical block subassembly includes a first optical path length between the inner surface of the recessed region and the outer surface of the cable-facing surface, the first optical path length being substantially equal to a second optical path length between the inner surface of the recessed region and the second surface of the transparent plate.

34. The optical block subassembly of any one of claims 30 to 33 further includes a reflective surface cover.

35. An optical interface comprising: a photoelectric element contact surface of a wedge-shaped optical block, the photoelectric element contact surface including at least one type I alignment feature extending from the photoelectric element contact surface and including a plurality of type II alignment features extending from the photoelectric element contact surface; and a mating surface of a mating element, the mating surface including a plurality of recessed areas in the mating surface, wherein the plurality of type II alignment features are inserted into the plurality of recessed areas, and the at least one type I alignment feature contacts the mating surface, thereby passively aligning the wedge-shaped optical block and the mating element.

36. The optical interface of claim 35, further comprising a plurality of collimated beams passing through the optical interface.

37. The optical interface of claim 35, wherein the at least one type I alignment feature facilitates passive alignment of the optical block relative to the mating surface in the lateral, longitudinal, and lateral rotational orientations.

38. The optical interface of claim 37, wherein the plurality of type I alignment features includes at least three supports.

39. The optical interface of any one of claims 35 to 38, wherein the plurality of Type II alignment features are passively aligned with the wedge-shaped optical block relative to the mating surface in the longitudinal, lateral and transverse rotational orientations.

40. The optical interface of claim 39, wherein the plurality of type II alignment features comprises a plurality of wedges.

41. The optical interface of claim 40, wherein the plurality of wedges includes three wedges.

42. The optical interface of claim 41, wherein the three wedges include a longitudinally extending wedge and two laterally extending wedges.

43. The optical interface of claim 42, wherein the two laterally extending wedges are arranged along the bisectors of the lateral extensions.

44. The optical interface of claim 43, wherein the longitudinally extending wedge is arranged along the longitudinally extending bisector.

45. The optical interface of claim 44, wherein the longitudinally extending bisectors and the laterally extending bisectors intersect at a virtual center.

46. ​​The optical interface of any one of claims 36 to 38, wherein the plurality of collimated beams are arranged symmetrically about the virtual center.

47. The optical interface of claim 42, wherein the longitudinally extending wedge is longer than the two laterally extending wedges.

48. The optical interface of claim 43, wherein the plurality of wedges are arranged asymmetrically with respect to the laterally extending bisectors.

49. An optical interface as claimed in any of claims 35 to 38, wherein at least one of the plurality of type II alignment features includes deformation caused by its insertion into the recessed area therein.

50. The optical interface of claim 49, wherein the deformation is localized to be a portion of the sidewall of at least one of the plurality of type II alignment features.

51. The optical interface of any one of claims 35 to 38, wherein the mating element is a lens array.

52. A passively aligned optical interconnect system comprising: an optical block including a photoelectric element contact surface having a plurality of optical block alignment features; and a mating element including a plurality of mating element alignment features configured to mate with the plurality of optical block alignment features such that when the plurality of optical block alignment features mate with the plurality of mating element alignment features, the optical block is passively aligned with the mating element in six degrees of freedom.

53. The passively aligned optical interconnect system of claim 52, wherein the mating element is a lens array.

54. The passively aligned optical interconnect system of claim 52, wherein the mating element includes a substantially planar top surface.

55. The passively aligned optical interconnect system of claim 54, wherein the top surface of the substantially planar surface includes a plurality of recessed areas defining alignment features of the mating elements.

56. The passively aligned optical interconnect system of claim 55, wherein the plurality of optical block alignment features include a plurality of wedges and a plurality of supports.

57. The passively aligned optical interconnect system of claim 56, wherein the heights of each of the plurality of supports are equal.

58. The passively aligned optical interconnect system of claim 57, wherein the plurality of wedges includes longitudinally extending wedges and laterally extending wedges.

59. The passively aligned optical interconnect system of claim 58, wherein the longitudinally extending wedge and the laterally extending wedge have the same cross-sectional shape.

60. The passively aligned optical interconnect system of claim 59, wherein the cross-sectional shape is symmetrical about the bisecting plane.

61. The passively aligned optical interconnect system of claim 60, wherein both the longitudinally extending wedge and the laterally extending wedge include wedge sidewalls, and the wedge sidewalls include an upper section and a lower section.

62. The passively aligned optical interconnect system of claim 61, wherein the orientation angle of the upper segment is smaller than the orientation angle of the lower segment.

63. The passively aligned optical interconnect system of any one of claims 58 to 62, wherein the longitudinally extending wedge extends a greater distance in the longitudinal direction than the laterally extending wedge extends in the lateral direction.

64. The passively aligned optical interconnect system of any of claims 57 to 61, wherein the depth of each of the plurality of recesses is greater than the difference between the height of each of the plurality of wedges and the height of the plurality of supports, such that when the plurality of wedges engage with the plurality of recesses, the plurality of wedges do not touch the bottom.

65. The passively aligned optical interconnect system of any one of claims 57 to 62, wherein the width at the top of each of the plurality of recessed areas is equal to or approximately equal to the width of the plurality of wedges at the height of the plurality of supports within manufacturing tolerances.

66. The passively aligned optical interconnect system of claim 61, wherein the orientation angle of the upper section is greater than the orientation angle of the sidewalls of the plurality of recessed regions.

67. A passively aligned optical interconnect system as claimed in any of claims 52 to 62, wherein the optical block includes a substantially planar reflective surface that does not have optical power.

68. A passively aligned optical interconnect system as claimed in any of claims 52 to 62, wherein the optical block includes a cable-facing surface configured to engage with a detachable cable assembly.

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