METHODS FOR WELDING AN OPTICAL FIBER TO A PHOTONIC INTEGRATED CIRCUIT

Multiple methods are provided for fiber optic welding on a photonic integrated circuit (PIC). An example method includes providing a PIC, forming an attachment surface on the PIC configured to receive an optical fiber. The method further includes disposing at least a portion of the optical fiber on the attachment surface. The method may then include welding the optical fiber to secure the optical fiber with respect to the attachment surface. The attachment surface may be comprised of substantially the same material as an outer portion of the optical fiber and may result in a homogenous weld securing and connecting the optical fiber to the PIC.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Greek patent application Ser. No. 20230100170, filed Feb. 28, 2023, the entire contents of which application are hereby incorporated herein by reference.

TECHNOLOGICAL FIELD

Example embodiments of the present disclosure relate generally to optical fiber welding for photonic integrated circuits (PICs).

BACKGROUND

As the demand for data processing continues to increase, data transfer speeds have similarly needed to increase while keeping power consumption low. Chip-to-chip optical connections can reduce total power consumption by removing relay components. However, chip-to-chip connections may be used in conditions involving temperature stress and may create challenges for conventional material bonding techniques. Applicant has identified numerous deficiencies and problems associated with conventional fiber optic methods for creating chip-to-chip connections. Through applied effort, ingenuity, and innovation, many of these identified problems have been solved by developing solutions that are included in embodiments of the present disclosure, many examples of which are described in detail herein.

BRIEF SUMMARY

Embodiments of the present disclosure are directed to methods of welding an optical fiber to a photonic integrated circuit (PIC). In some embodiments, an attachment surface configured to receive an optical fiber may be formed on a PIC. A portion of the optical fiber may be at least partially disposed on the attachment surface. Securement of the optical fiber with respect to the attachment surface may be accomplished through welding. The attachment surface may be comprised of substantially the same material as an outer portion of the optical fiber. Welding of the optical fiber may result in a homogenous weld for securing and connecting the optical fiber to the PIC.

In some embodiments, the attachment surface comprises a V-shaped groove defined by the PIC.

In some embodiments, optical beads may be disposed within the groove. The optical beads may be configured to facilitate welding of the optical fiber.

In some embodiments, the PIC defines a V-shaped groove. Forming the attachment surface may comprise disposing a silicon dioxide passivation layer on the V-shaped groove.

In some embodiments, the PIC defines a V-shaped groove and forming the attachment surface may be comprised of applying at least one mirror to a surface of the V-shaped groove. The at least one mirror may be configured to focus the welding of the optical fiber within the groove.

In some embodiments, the optical fiber may be cleaved to correspond to a shape of the attachment surface.

In some embodiments, a glass slab may be affixed to the optical fiber. The glass slab may be configured to extend to an area of the optical fiber for engagement with the attachment surface to facilitate welding.

In some embodiments, the PIC defines a groove having a curved cross-section. The attachment surface may be the surface of the groove.

In some embodiments, the attachment surface comprises a passivation layer comprising silicon dioxide.

In some embodiments, the method may comprise welding a silicon dioxide chip to an outer portion of the optical fiber. Welding the optical fiber onto the attachment surface may comprise welding the silicon dioxide chip to the passivation layer.

In some embodiments, the silicon dioxide chip may comprise a silicon nitride waveguide.

In some embodiments, the method may comprise affixing an extension to the optical fiber. Welding of the optical fiber may comprise welding the extension to the attachment surface.

In some embodiments, the affixed extension to the optical fiber may be a glass slab.

In some embodiments, the extension may be a prism.

In some embodiments, the prism may comprise a lens.

In some embodiments, the method may comprise disposing an intermediate material between the optical fiber and passivation layer.

In some embodiments, the intermediate material comprises a lens. The prism may be configured to direct an optical signal from the optical fiber into a waveguide of the PIC via the lens.

In some embodiments, the method may comprise affixing an optical glass substrate to the optical fiber. Welding the optical fiber may comprise welding the optical glass substrate to the attachment surface. The optical glass substrate may define an angled end configured to be welded to the attachment surface such that a predetermined working distance and angle for coupling is achieved.

A method for attaching an optical fiber to a photonic integrated circuit (PIC) may further comprise providing a PIC. A groove may further be defined in the PIC, and the groove may comprise an attachment surface configured to receive an optical fiber. The method may further include disposing a passivation layer of silicon dioxide on the attachment surface. At least a portion of the optical fiber may be disposed for receipt by the attachment surface. The method may further include welding the optical fiber to secure the optical fiber with respect to the attachment surface.

In some embodiments, the groove may be a V-shaped groove or have a curved cross section.

DETAILED DESCRIPTION

Embodiments of the present disclosure now will be described more fully hereinafter with reference to the accompanying drawings in which some but not all embodiments are shown. Indeed, the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. As used herein, terms such as “front,” “rear,” “top,” etc. are used for explanatory purposes in the examples provided below to describe the relative position of certain components or portions of components. Furthermore, as would be evident to one of ordinary skill in the art in light of the present disclosure, the terms “substantially” and “approximately” indicate that the referenced element or associated description is accurate to within applicable engineering tolerances.

An optical fiber is a flexible, transparent fiber made by drawing glass or plastic to a compressed diameter. Optical fiber may be used for telecommunications, long distance transmissions, power transmissions, light transmissions, sensor applications, and computer networking. An optical fiber may include a core surrounded by a cladding material with a lower index of refraction. In some cases, an optical fiber may include a cylindrical dielectric waveguide that transmits light along its axis through a process of total internal reflection. Materials used in the creation of optical fibers may include silica, fluorozirconate (fluoride glass), fluoroaluminate, chalcogenide glasses, crystalline materials and/or a combination of such materials.

A photonic integrated circuit (PIC) may refer to a microchip containing two or more photonic components that form a functioning circuit. In general, photonic components are components that are capable of detecting, generating, transporting, and/or processing light. PICs may include materials such as silicone, silicon nitride, silicon photonics, silica, lithium niobate, indium phosphide, and/or gallium arsenide. For example, a PIC may be made of a glass or silicon substrate and may include a waveguide made of silicon or silicon nitride and a passivation layer made of silicon dioxide.

Several conventional methods exist for connecting optical fibers with PICs for facilitating optical communication. Many of these rely on fibers mounted in ferrules or silicon V-groove chips using polymer adhesives, metal soldering, or laser welding. Welding involves the process of heating individual pieces or parts to the point of melting and subsequently fusing the pieces or parts together. Welding may be achieved through the use of a high-powered laser, blowtorch, electric arc, or other device used to generate heat for fusing the pieces together. Welding of the optic fiber may be conducted through welding single fibers or multiple element welding.

Conventional methods for forming connections between optical fibers and PICs are often prone to failure due to differences in thermal expansion coefficient between bonded surfaces, polymer degradation, uneven curing, or low melting temperature of the adhesive used. Additionally, silica-based optical fibers for chip-to-chip connections may be more at risk of failure due to use in harsh conditions and environments. Said conditions and environments may include varying temperatures or extreme operating conditions. Optical fibers may further experience temperature stress through temperature changes that may occur during or after installation. For example, the use of high-powered lasers to install or modify the optical fibers or system can cause significant temperature changes that can result in damage or failure. Bonding or welding materials that are mismatched or have incompatible material characteristics may further result in energy losses during operation, which can cause an increase in total power consumption.

In order to address these issues and others, embodiments of the present invention are directed to improved methods of welding an optical fiber to a PIC. In particular, embodiments of the methods described herein provide for components to be welded together such that the welded surfaces are homogeneous or have the same or similar material characteristics, thereby circumventing problems arising from a mismatch in material properties of the substrate, optic fiber, and/or the bonding material. As described in greater detail below, embodiments of the optic fiber welding methods described herein may thus be used to create strong, homogenous bonds with an increased tensile strength, which can reduce the incidence of failure and reduce the amount of power needed to overcome energy losses that may otherwise occur.

With reference toFIG.1, an attachment of an optical fiber102to a photonic integrated circuit (PIC)104according to one embodiment is illustrated. As described above, the optical fiber102comprises a core103surrounded by cladding material101. The cladding material101may be made of glass or a material with a lower index of refraction as compared to the core103, as previously noted. As will be understood by one skilled in the art in light of this disclosure, the core103may serve as a waveguide, allowing light (e.g., an optical signal) to be propagated therethrough.

As noted above, the PIC104may comprise two or more photonic components, such as components capable of detecting, generating, transporting, and/or processing light. For example, in some cases, the PIC104may comprise a waveguide108that is configured to confine and convey an optical signal therethrough. In some cases, the PIC104may further comprise a passivation layer110. The passivation layer110may form the outer layer of the PIC104and, as such, in some embodiments may overlie the waveguide108, as shown inFIG.1.

The passivation layer110may be a coating of a predetermined thickness that is configured to make the surface of the PIC104less reactive to chemical treatment. The passivation layer110may protect the surface of the PIC104from contamination, such as contamination that may otherwise occur during coating or surface treatment of the PIC. The prevention of contamination may further promote the strength of bonds created through welding (e.g., the bonds between the PIC104and the optical fiber102), as contamination may reduce the otherwise homogenous nature of the materials being welded by introducing other materials to the juncture. The passivation layer110may, in some cases, be made of silicon dioxide or other materials with properties that protect the PIC104from foreign contaminants and resist chemical reaction, while also matching or being of a similar material to the material of the optical fiber102and/or the PIC that are being welded together.

In optical communications, an optical signal is often transmitted through an optical fiber and into a PIC, such as the optical fiber102and the PIC104shown inFIG.1. As noted above, the optical fiber102and the PIC104must therefore be coupled in such a way as to allow optical signals to pass therebetween. One way to couple the optical fiber102and the PIC104is to weld these components together. Accordingly, to embodiments described herein, a homogeneous weld is created for securing the optical fiber102with respect to the PIC104by forming an attachment surface106on the PIC104. The attachment surface106may be configured to receive the optical fiber102. The homogenous weld may be formed by welding the optical fiber102(e.g., the cladding material101and/or the core waveguide103) to the PIC104via the attachment surface106, including any components included as part of the attachment surface, as described herein.

The attachment surface106may, for example, be a region, area, or zone that is formed on the PIC104that is configured to receive the optical fiber102and allows the PIC104and the optical fiber to be bonded together, such as via a welding operation, in such a way as to form a homogeneous weld.

The attachment surface106may have various configurations and may be formed in various ways. For example, in some embodiments, the attachment surface106may be formed directly in the material of the PIC104. In other embodiments, such as the embodiment illustrated inFIG.1, the attachment surface106may be formed in or otherwise comprise the passivation layer110. In still other embodiments, described in greater detail below, the attachment surface106may comprise intermediate materials, such as additional components or structures, that are configured to perform a function with respect to the optical fiber102and/or the PIC104and are further configured to facilitate or enhance the homogenous weld.

The optical fiber102may be a single fiber or multiple fibers. In some embodiments, the outer portion of the optic fiber102(e.g., an outer surface of the optical fiber) may comprise a material that is the same or similar to the material(s) of the attachment surface106, regardless of its configuration.

With continued reference toFIG.1, at least a portion of the optical fiber102(e.g., an end of the optical fiber) may be disposed on the attachment surface106. The optical fiber102may be welded to secure the optical fiber with respect to the attachment surface106. Welding the optical fiber102may create a bond between the optical fiber102and the PIC104. Because the attachment surface106comprises substantially the same material as an outer portion of the optical fiber, welding the optical fiber102results in a homogenous weld for securing and connecting the optical fiber102to the PIC104. The PIC104may be configured to be reworkable after welding operations have been conducted on the PIC and optical fiber102. For example, in the case of a failed attachment or faulty connection between a PIC104and components received by the PIC or an optical fiber102, additional corrective welds may be performed to repair the failures.

With reference toFIG.2, a transverse cross-section (e.g., a cross-section taken perpendicular to the longitudinal axis of an optical fiber102) is shown. As depicted, in some embodiments, the PIC104may define a groove, such as a V-shape groove206as shown, and the attachment surface106may comprise the V-shaped groove defined by the PIC. The optical fiber102may be at least partially disposed in the V-shaped groove206. The V-shaped groove206may be configured (e.g., sized and shaped) to have a depth and angle as determined by a user based on a number of factors, such as the dimensions of the optical fiber102and the dimensions of the PIC104. The V-shaped groove206may, for example, be configured to optimize the contact area between the optical fiber102and the attachment surface106formed on the V-shaped groove206. Furthermore, in cases where of multiple fibers or an array of optical fibers is to be received by and connected to the PIC104, the PIC104may define multiple V-shaped grooves206and corresponding attachment surfaces106to connect the plurality of fibers.

With reference toFIG.3, optical beads301may be disposed in the V-shaped groove206in some embodiments to facilitate welding of the optical fiber102to the attachment surface106. In such embodiments, the optical beads301may be placed in proximity to the optical fiber102and the attachment surface106of the V-shaped groove206. The optical beads301may consist of the same or similar material as the optical fiber102and/or the PIC104and may be welded with the optical fiber102to create a homogenous weld for securing and connecting the optical fiber to the PIC. Said differently, the optical beads301may melt during the welding process and bond with both the optical fiber102and the PIC104to secure and connect them to each other via the attachment surface106. In this way, the optical beads301may serve to increase the contact area between the optical fiber102and the attachment surface106by surrounding the optical fiber and more thoroughly connecting the optical fiber with the PIC104. Placement of the optical beads301may be above the optical fiber102while the optical fiber is disposed in the V-shaped groove206, below the optical fiber, or in both positions within the V-shaped groove206. Welding of the optical fiber102within the V-shaped groove206with the additional material provided by the optical beads301may thus increase the strength and size of the bond formed with the PIC104while creating a homogeneous weld as described above. The dimensions and number of optical beads301used may be determined by the user based on a number of factors, such as the dimensions of the optical fiber102and the dimensions of the V-shaped groove106.

With reference toFIG.4and as noted above, in some embodiments the PIC104defines a V-shaped groove206, and the attachment surface106is formed by disposing a silicon dioxide passivation layer401onto the V-shaped groove. In such embodiments, the silicon dioxide passivation layer(s)401may be disposed on the walls of the V-shaped groove206, as shown inFIG.4, and may serve to make the surface of the PIC104(e.g., at the V-shaped groove206) less reactive to chemical treatment and to protect it from contamination that may otherwise occur during coating processes or surface treatment, as described above. The silicon dioxide passivation layer(s)401may further prevent corrosion of the PIC104and may reduce the possibility that the material involved in the welding of the optical fiber102includes foreign contaminants. The thickness of the silicon dioxide passivation layer401may be determined based on a number of factors, including the material of the PIC104and the processes that the PIC and optical fiber102will undergo, among others. The silicon dioxide passivation layer401may be attached to the surface of the V-shaped groove206using an adhesive, and welding of the optical fiber102may bond the optical fiber to the passivation layer, creating a homogenous weld based on the material used for the passivation layer according to the embodiments described herein.

In some embodiments, a material similar to the cladding of the optical fiber102may be used in place of silicon dioxide to create a passivation layer. The passivation layer may be constructed using a material such as glass, silica, plastic, or other material with an index of refraction that is lower than that of the core and may perform similar functions as the silicon dioxide passivation layer401.

With reference toFIG.5, in some embodiments in which the PIC104defines a V-shaped groove206, the attachment surface106may be formed by applying at least one mirror501to a surface of the V-shaped groove. The at least one mirror501may be configured to focus laser welding of the optical fiber102within the groove. The at least one mirror501may, for example, be made of material that reflects and/or redirects the welding energy (e.g., the laser light used in laser welding) to concentrate the energy on the areas to be welded (e.g., the contact areas between the optical fiber102and the PIC104). The at least one mirror501may, for example, be made of gold or aluminum in some cases. In some embodiments, a passivation layer401as shown inFIG.4may be disposed on top of the at least one mirror501(not shown). In such cases, the welding energy (e.g., the laser light) may pass through the passivation layer401to the at least one mirror501underneath to be focused by the at least one mirror. In some cases, as shown inFIG.5, one or more mirrors501may be applied to each side of the V-shaped groove206. Furthermore, mirrors may be placed above and/or below the optical fiber102. Placement of the at least one mirror501below the optical fiber102may allow the mirror to function as a protective layer during the welding process, protecting potentially sensitive parts of the PIC104.

In some embodiments, the PIC104may define a groove806having a curved cross-section, as shown inFIG.8, and the attachment surface106may be the surface of the groove. The curved groove806may have a radius of curvature equal to or greater than the radius of the optical fiber102. In some cases, the curvature of the curved groove806may approach the curvature of the outer surface of the optical fiber102, such that the contact area between the optical fiber and the groove (and, as such, the attachment surface106) is maximized when the optical fiber is disposed in the groove. Due to the greater contact area between the optical fiber102and the PIC104, welding tolerances may be increased, and the welding process may be optimized to create a stronger and more stable weld.

In other embodiments, the attachment surface106formed on the PIC104may not be a groove defined in the PIC, but rather may be an outer surface of the PIC, as shown inFIG.6. In such embodiments, the optical fiber102may be cleaved to correspond to a shape of the attachment surface106. For example, the optical fiber102may be at least partially cleaved, cut, sheared, or otherwise have its physical shape modified to correspond to the shape of the attachment surface106of the PIC104. In this way, the contact area between the optical fiber102and the attachment surface106, and thereby the PIC104, may be maximized. InFIG.6, for example, the optical fiber102has a circular transverse cross-section, similar to that shown inFIGS.2-5. The cross-section shown inFIG.6is taken along a longitudinal axis of the optical fiber. The PIC104in the depicted example may have a rectangular shape (e.g., rectangular prism). Thus, in the embodiment depicted inFIG.6, the bottom portion of the optical fiber102(the portion to contact the attachment surface106) may be cleaved using a longitudinal cut and a transverse cut to create a larger flat surface606with a right angle that is configured to correspond with the attachment surface106of the PIC104to create more thorough contact and engagement therebetween. In some embodiments (not shown), the cleaved surface606may engage a passivation layer110of the PIC104. The passivation layer may be similar to the passivation layer110shown inFIG.4and described above.

In some embodiments, as depicted inFIG.7, rather than change the shape of the optical fiber102by cutting away a portion, such as with the cleaving process described above, in some embodiments a glass slab702may be affixed to the optical fiber. The glass slab702may be configured to extend an area of the optical fiber102for engagement with the attachment surface106to facilitate the welding. The glass slab702may be affixed to the optical fiber102to both add material that is similar to the optical fiber and/or the attachment surface106, which may promote homogenous welding of the optic fiber to the PIC104and increase the contact area between the optical fiber and the attachment surface. Attachment of the glass slab702to the optical fiber102may be performed through a separate welding process and may further occur before attachment of the optical fiber to the PIC104. The dimensions of the glass slab702may be configured based on the dimensions of the optical fiber102and the attachment surface106, among other factors. As described above in connection with other embodiments, in some cases, the PIC104may include a passivation layer110and a waveguide108.

In embodiments wherein the attachment surface106comprises a passivation layer110(e.g., a passivation layer comprising silicon dioxide), a silicon dioxide chip901may be welded to an outer portion of the optical fiber102, as shown inFIG.9. In such embodiments, welding the optical fiber102onto the attachment surface106may comprise welding the silicon dioxide chip901to the passivation layer110. The silicon dioxide chip901may comprise a silicon nitride waveguide902, which may act in similar manner as the waveguide108in the PIC104. The silicon dioxide chip901and the silicon nitride waveguide902may be attached to the optical fiber102through a separate weld operation conducted before the optical fiber is welded to the PIC104via the attachment surface106. The silicon dioxide chip901may, in some cases, be 3D-printed and configurable, such as by modifying the dimensions and/or modifying the silicon nitride waveguide902within the chip for a given PIC104. The silicon nitride waveguide902may be shaped and/or oriented (e.g., positioned and angled) to direct optical signals toward the attachment surface106, such as through the use of a sloped section905of the waveguide902. The sloped section905of the silicon nitride waveguide902may be configured to direct optical signals from the optical fiber102toward the waveguide108in the PIC104. The silicon nitride waveguide902may be configured to be placed within a predetermined distance (such as 1 micron) from the edge of the silicon dioxide chip907closest to the attachment surface106. An optical signal traveling through the optical fiber102and within the silicon nitride waveguide902may thus be transmitted to the waveguide108of the PIC104due to the close proximity.

In continued reference toFIG.9, the silicon dioxide chip901may be secured to the attachment surface106due to welding of the optical fiber102, thereby securing the optical fiber to the PIC104with a homogenous weld. Said differently, due to the similar material characteristics of the silicon dioxide chip901and the attachment surface106(e.g., similar silicon content to the passivation layer110that creates a silicon-on-silicon weld), a homogenous weld can be formed. In some cases, the optical fiber102may be welded to the silicon dioxide chip901as described above. However, the silicon dioxide chip901may be secured to the PIC104through the application of an adhesive glue. An adhesive used to secure the silicon dioxide chip901to the PIC may enable the transmission of optical signals between the optical fiber102and the PIC104without interference.

In still other embodiments wherein the attachment surface106comprises a passivation layer110, an extension may be affixed to the optical fiber102and welding the optical fiber may comprise welding the extension to the attachment surface. For example, the extension may be affixed to the end of the optical fiber102, and the extension may be a glass slab, such as the glass slab107shown inFIG.7and described above. In other embodiments, such as shown inFIGS.10-12, the extension affixed to the optical fiber102may be a prism1005. The prism1005may be made of a material similar to the optical fiber102or PIC104, such as silicon dioxide, silica, glass, etc. The prism1005may be configured (e.g., sized and shaped) to correspond to the dimensions of the optical fiber102. The prism1005may be attached to the optical fiber102through a welding process before the attachment of the optical fiber to the PIC104. In other embodiments, the prism1005may further function as a waveguide and assist in directing optical signals from the optical fiber102toward the waveguide108within the PIC104.

Additionally, in some embodiments, an intermediate material1003may be disposed between the optical fiber102and the passivation layer110. The intermediate material1003may be made of materials similar to the optical fiber102and/or the PIC104to promote creation of a homogenous weld. The intermediate material1003may further serve to protect the PIC104during the welding process. The thickness of the intermediate material1003may be selected to maximize protection of the PIC104during the welding process. Additionally, in some embodiments, other components configured to transmit, propagate, process, or otherwise interact with the optical signal being carried by the optical fiber102and/or the PIC104may be incorporated. For example, according to the particular embodiments depicted inFIGS.10-12, a grating coupler1001may be embedded within the waveguide108of the PIC104. The grating coupler1001may be configured to have a predetermined length and period based on the desired coupling capabilities and may further be configured to allow certain optical signals to pass therethrough and into the waveguide108in the PIC104. The intermediate material1003may be configured to set a working distance between the optical fiber102and the grating coupler1001.

With reference toFIG.12, in some embodiments the intermediate material1003may comprise a lens1107. The prism1005may, in some cases, be configured to direct an optical signal from the optical fiber102into a waveguide108of the PIC104via the lens1107. For example, the prism1005may be used to direct the optical signal traveling through the optical fiber102toward the grating coupler1001.

In other embodiments, however, the lens1107may be separate from the intermediate material1003. For example, the lens1107may, in some cases, be embedded within the prism1005, such as when the prism1005comprises the lens. In still other embodiments, the lens1107may be affixed to a surface of the prism, such as depicted inFIG.11.

Turning now toFIG.13, in some embodiments, an optical glass substrate1301may be affixed to the optical fiber102. Welding the optical fiber102may, in such embodiments, comprise welding the optical glass substrate1301to the attachment surface106. The optical glass substrate1301may define an angled end1303configured to be welded to the attachment surface106such that a predetermined working distance d and angle for coupling is achieved. The optical glass substrate1301may thus be configured (e.g., sized, shaped, angled, etc.) to adjust the distance d and substrate angle1307based on the dimensions of the PIC104and/or other components in the system. The optical glass substrate1301may, in some cases, be adhered or welded to an outer surface of the optical fiber102and may further be secured to the PIC104through welding with the intermediate material1003and/or the attachment surface106. The optical glass substrate1301may further allow the optical signal to travel from the optical fiber102, across the gap between the optical fiber and intermediate layer1003and toward the grating coupler1001. The configuration of the optical glass substrate1301(e.g., the substrate angle1307) sets the distance d between the optical fiber102and the grating coupler1001.

Referring toFIG.14, a method of attaching an optical fiber102to a PIC104is shown that may comprise providing a PIC104(Block1402) and defining a groove in the PIC (Block1404). The PIC104may be modified to define a groove to facilitate welding of the optical fiber102. The groove may take the form of a V-shaped groove, a curved-cross section groove, a U-shaped groove, or the like. The attachment surface106of the PIC104embodied in the form of a groove may add stability to the chip-to-chip connection, enable welding at lower temperatures (thus decreasing possible damage that may occur to the chip or PIC104), and increasing the amount of welding position tolerance. Welding within the attachment surface106as embodied by a groove may further add two dimensions of stability to the bond created between the optical fiber and the PIC104in terms of pulling and bending strength. A passivation layer110of silicon dioxide may be disposed on the attachment surface106(Block1406). The passivation layer110may refer to a thin layer of a similar material as the optical fiber102and the PIC104and may further be modified during the attachment process to form a homogenous weld used for securing and connecting the optical fiber to the PIC. At least a portion of the optical fiber102may then be disposed for receipt by the attachment surface106(Block1408). The portion of the optical fiber102disposed for receipt may further include an extension of the optical fiber in the attachment surface106. Said extension of the optical fiber102may include a glass slab, a silicon dioxide chip, a prism, a lens attachment, or the other embodiments described previously. The optical fiber102may then be welded to secure the optical fiber with respect to the attachment surface106(Block1410). The welding of the optical fiber102to the attachment surface106may include elements previously described, such as a passivation layer, intermediate material, waveguide, or other such elements that may experience welding during the attachment process. The method may further include securing at least one mirror to the attachment surface. The at least one mirror may be configured to focus the welding of the optical fiber with the attachment surface, in a manner similarly described inFIG.5.

Referring now toFIG.15, embodiments of another method of attaching an optical fiber102to a PIC104is shown that may comprise a PIC104may be provided (Block1502). An attachment surface106may then be formed on the PIC104that may be configured to receive an optical fiber102. At least a portion of the optical fiber102may be disposed onto the attachment surface106(Block1506). The optical fiber102may then be welded with respect to the attachment surface106(Block1508). The attachment surface106may be comprised of substantially the same material as an outer portion of the optical fiber102, resulting in a homogenous weld for securing and connecting the optical fiber to the PIC104.

As described above with respect toFIGS.1-13, the optical fiber102may be welded to the PIC104in various ways using different methods to achieve the desired configuration and/or functionality. For example, in embodiments in which the attachment surface106comprises a V-shaped groove206defined by the PIC104, optical beads301may be disposed within the groove. Additionally, or alternatively, forming the attachment surface may comprise disposing a silicon dioxide passivation layer onto the V-shaped groove. In some cases, at least one mirror501may be applied to at least one surface of the V-shaped groove. The at least one mirror501may be configured to focus the welding of the optical fiber102within the groove, as described above. In another embodiment, the optical fiber102may be cleaved to correspond to a shape of the attachment surface106, as described above. In other embodiments, a glass slab702may be affixed to the optical fiber102. The glass slab702may be configured to extend an area of the optical fiber102for engagement with the attachment surface106to facilitate welding. In some embodiments, the attachment surface may comprise a passivation layer110comprising silicon dioxide, and a silicon dioxide chip901may be welded to an outer portion of the optical fiber102. Welding the optical fiber102onto the attachment surface106may comprise welding the silicon dioxide chip901to the passivation layer110. The silicon dioxide chip901may, in some embodiments comprise a silicon nitride waveguide902.

In other embodiments including the passivation layer110, an extension may be affixed to the optical fiber102and welding the optical fiber may comprise welding the extension to the attachment surface106. Affixing the extension to the optical fiber102may comprise affixing the extension to an end of the optical fiber, and the extension may be a glass slab702, as described above. The extension may, in some cases, include a prism1005, a lens1107, or a combination of both. In other embodiments, an optical glass substrate1301may be affixed to the optical fiber102. Welding the optical fiber102may comprise welding the optical glass substrate1301to the attachment surface, and the optical glass substrate may define an angled end1303configured to be welded to the attachment surface such that a predetermined working distance d and angle for coupling1307is achieved.

Many modifications and other embodiments of the present disclosure set forth herein will come to mind to one skilled in the art to which these embodiments pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Although the figures only show certain components of the methods and systems described herein, it is understood that various other components may also be part of any optical component or optoelectronic element. In addition, the methods described above may include fewer steps in some cases, while in other cases may include additional steps. Modifications to the steps of the method described above, in some cases, may be performed in any order and in any combination.