Optical connectors that use thermal expansion to maintain alignment

Abstract

The optical assembly includes an optical ferrule configured to receive an input light beam through an input location on a major input face of the optical ferrule along a first direction for coupling to an optical waveguide secured to the optical ferrule, the optical ferrule including a reference location, wherein a temperature change in the optical assembly causes the input light beam and the input location to move distances d1 and d2, respectively, along the same axis and in the same direction, rather than to the reference location, wherein the magnitude of d1-d2 is δ, and the maximum magnitudes of d1 and d2 are greater than 10 times δ.

Description

Summary of the Invention

[0001] In some aspects of the present specification, there is provided an optical assembly including an optical ferrule, the optical ferrule configured to receive an input light beam through an input location on a major input face of the optical ferrule along a first direction for coupling to an optical waveguide secured to the optical ferrule, the optical ferrule having a reference position, and a temperature change in the optical assembly causes the input light beam and the input location, rather than the reference position, to move distances d1 and d2 along the same axis and in the same direction, respectively, wherein the magnitude of d1-d2 is δ, and the maximum value of the magnitudes of d1 and d2 is greater than 10δ.

[0002] In some aspects of the present specification, there is provided an optical assembly including an optical ferrule having an optical waveguide fixed to the optical ferrule, and an optical component, wherein the optical ferrule is configured to receive light from the optical component and couple the received light to the optical waveguide, such that when the optical ferrule and the optical component are at a temperature T1, the optical ferrule is aligned with the optical component to optimize the optical coupling of the received light to the optical waveguide, and by moving the received light a first distance while maintaining the temperature of the optical ferrule and the optical component at T1, the optical coupling of the received light to the optical waveguide is reduced by at least 10%, and by changing the temperature of the optical ferrule and the optical component from T1 and moving the received light a first distance, the optical assembly reduces the optical coupling of the received light to the optical waveguide by less than approximately 10%.

[0003] In some aspects of the present specification, an optical assembly is provided that includes an optical ferrule having an optical waveguide secured to the ferrule, an optical component, the optical ferrule being configured to receive light from the optical component through an input position of the ferrule and optically couple the received light to the optical waveguide, and a cradle that secures the optical ferrule therein and aligns the optical ferrule with the optical component, wherein when the temperature of the optical assembly changes, the received light and the input position each move in the same direction along the same axis, and the optical coupling of the received light to the optical waveguide is reduced by approximately 10% or less.

[0004] In some aspects of the present disclosure, an optical assembly is provided that includes an optical ferrule assembly and a cradle. The optical ferrule assembly includes an optical ferrule having a mounting region and an optical redirecting side, the optical ferrule including an optical waveguide secured to the mounting region. The optical ferrule of the optical ferrule assembly can be secured within the cradle. When an input light beam enters the optical ferrule through an input position of the optical ferrule and is optically coupled to the optical waveguide after being redirected by the optical redirecting side, a temperature change in the optical ferrule assembly causes the input light beam and the input position to move, such that the input light beam continues to enter the optical ferrule through the input position, but the reference position of the optical assembly does not move. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a perspective view of an optical assembly according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a perspective view of an optical ferrule assembly according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is an alternative perspective view of an optical ferrule assembly according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a side cutaway view of an optical assembly in operation according to an embodiment herein. [Figure 5A]1A-1C are schematic side views of an optical assembly illustrating system behavior at different temperatures, according to an embodiment herein. [Figure 5B] 1A-1C are schematic side views of an optical assembly illustrating system behavior at different temperatures, according to an embodiment herein. DETAILED DESCRIPTION OF THE INVENTION

[0006] In the following description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration various embodiments. The drawings are not necessarily to scale. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the specification. Accordingly, the following detailed description is not to be taken in a limiting sense.

[0007] There are optical systems in which an expanded (i.e., substantially collimated) optical beam can undergo lateral translation due to temperature changes. For example, this translation can occur when an optical beam travels at an oblique angle through a slab of material (e.g., glass with parallel input and output faces). The refractive index of the material can change with temperature, so the angle of the beam traveling through the material can change. Typically, the output beam remains substantially parallel to the input beam, but the lateral offset between the output and input beams changes with temperature. If this beam is captured by a conventional optical ferrule and focused into an optical fiber, misalignment of the expanded beam and the optical ferrule can result in temperature-dependent efficiency loss. Expanded-beam connectors between planar waveguides and optical fibers (e.g., using prisms or grating couplers and collimating lenses) can also suffer from temperature-dependent offset of the expanded beam.

[0008] According to some aspects herein, components of an optical assembly may be configured to use thermal expansion and / or contraction of the components of the assembly (e.g., an optical ferrule) to substantially maintain alignment between an optical waveguide and a corresponding optical component over a wide temperature range. For example, the thermal expansion / contraction of the optical ferrule may be used to move an input window of the optical ferrule to accurately track the lateral offset of the expanded beam during temperature changes.

[0009] In some embodiments, the optical assembly includes an optical ferrule. In some embodiments, the optical ferrule is configured to receive an input light beam through an input location on a primary input face of the ferrule (e.g., a surface of the ferrule facing a mating component or an optical component providing the input light beam) along a first direction for coupling to an optical waveguide (e.g., an optical fiber) secured to the ferrule. In some embodiments, the ferrule can have a reference position, and a change in temperature of the optical assembly (e.g., a change of at least 5° C., or at least 10° C., or at least 15° C.) (causing thermal expansion or contraction of a system component) causes the input light beam and the input location to move distances d1 and d2, respectively, along the same axis (e.g., the x-axis) and in the same direction (e.g., the +x direction), where d1-d2 has a magnitude δ and the maximum magnitude of d1 and d2 is greater than 10 times δ. In other words, in some embodiments, the optical ferrule may be configured such that there is at least one position (i.e., a "reference position") that remains substantially in place during thermal changes (e.g., expansion or contraction of the optical ferrule or other system components). For example, the optical ferrule may be designed to have a center of thermal expansion that remains in a fixed position relative to a mating piece (e.g., a cradle configured to mate with and hold the optical ferrule). In some embodiments, the optical assembly may have an operating temperature range, and changes in temperature across the operating temperature range may cause the input beam and input position, rather than the reference position, to move distances d1 and d2, respectively, along the same axis (e.g., the x-axis) and in the same direction (e.g., +x). In some embodiments, the magnitude of d1-d2 is δ, and the maximum magnitude of d1 and d2 is greater than 10 times δ. In some embodiments, the operating temperature range of the optical assembly may be from about -40°C to about 100°C.

[0010] In some embodiments, an increase in temperature of the optical assembly may cause the input light beam and input position to move away from the reference position. In some embodiments, an increase in temperature may cause the input light beam and input position to move toward the reference position. In some embodiments, the reference position may be at or near a major surface of the optical ferrule. For example, the reference position may be within about 5 microns, about 10 microns, or about 15 microns of a mating face of the optical ferrule (e.g., the surface of the ferrule that faces a corresponding mating component). In some embodiments, the major surface may be a major input face of the optical ferrule. That is, the reference position may be within about 5 microns, about 10 microns, or about 15 microns of the major input face.

[0011] In some embodiments, the optical ferrule can be configured to redirect an input light beam received from a first direction to a different second direction. In some embodiments, the optical ferrule can have a light redirecting side or surface that can reflect the input light beam along a second direction. In some embodiments, the optical ferrule can include a mounting region (e.g., a groove or channel) for securing one or more optical waveguides (e.g., optical fibers). In some embodiments, the optical ferrule can have a light redirecting surface or side for receiving light from an optical waveguide (secured to the mounting region) along a first direction and redirecting the received light along a different direction. In some embodiments, the reference location and the mounting region can be located on the same side of the light redirecting side. In some embodiments, the reference location and the mounting region can be located on opposite sides of the light redirecting side.

[0012] In some embodiments, the optical ferrule may receive an input light beam from an optical component. In some embodiments, the optical component may be, but is not limited to, a photonic integrated circuit (PIC), a lens, a prism, a grating, a sensor, or a vertical cavity surface-emitting laser (VCSEL). In some embodiments, one or more properties of the optical component itself may change with a change in temperature. For example, with a sufficient change in temperature, the pitch of an optical grating as well as the refractive index of the grating's material may change. For example, as the temperature increases, the pitch of the grating may increase, decreasing the refractive index and causing the input light beam (light beam emitted by the optical component) to shift laterally (e.g., after passing through a collimating lens). This change in properties and the resulting lateral shift may be compensated for as described herein (e.g., by designing the thermal expansion of the optical ferrule to compensate for the lateral shift). In some embodiments, a change in temperature of the optical component may cause the input light beam to shift, while a change in temperature of the optical ferrule may cause the input position to shift.

[0013] In some embodiments, the optical assembly may include a cradle configured to secure the optical ferrule therein and align the optical ferrule relative to the optical component. For example, in some embodiments, the cradle may be mounted on an integrated circuit, printed circuit board, or similar substrate, positioned relative to the optical component on the substrate, such that the cradle and mated optical ferrule are held in proper position relative to the optical component. In some embodiments, the optical component may be, but is not limited to, a PIC, a lens, a prism, a grating, a sensor, or a VCSEL. In some embodiments, the cradle may define a reference position for the optical ferrule. That is, the reference position of the optical ferrule may be defined relative to a corresponding position on the cradle. In some embodiments, the thermal expansion coefficient of the cradle may be significantly (e.g., at least 5 times, or at least 10 times, or at least 15 times) smaller than the thermal expansion coefficient of the optical ferrule.

[0014] According to some aspects of the present disclosure, an optical assembly includes an optical ferrule having an optical waveguide (e.g., an optical fiber) secured to the optical ferrule, and an optical component (e.g., a PIC, a lens, a prism, a grating, etc.). In some embodiments, the optical waveguide can be an optical fiber having a cord with a diameter of about 5 to about 15 microns. In some embodiments, the optical ferrule can be configured to receive light from the optical component and couple the received light to the optical waveguide. In some embodiments, the optical ferrule can be configured such that when the optical ferrule and the optical component are at a temperature T1, the optical ferrule is substantially aligned with the optical component to optimize optical coupling of the received light to the optical waveguide. In some embodiments, by moving the received light a first distance while maintaining the temperature of the optical ferrule and the optical component at T1, optical coupling of the received light to the optical waveguide can be reduced by at least 10%, or at least 15%, or at least 20%. In some embodiments, changing the temperature of the optical ferrule and optical components from T1 may cause the received light to move a first distance, reducing the optical coupling of the received light into the optical waveguide by less than about 5% or less than 10%.

[0015] According to some aspects of the present disclosure, an optical assembly includes an optical ferrule having an optical waveguide (e.g., an optical fiber) secured to the optical ferrule, an optical component (e.g., a PIC, a lens, a prism, a grating, etc.), and a cradle that secures the optical ferrule therein and aligns the optical ferrule to the optical component. In some embodiments, the optical ferrule can be configured to receive light from the optical component through an input position and optically couple the received light to the optical waveguide. In some embodiments, when the temperature of the optical assembly changes, each of the received light and the input position can move along the same axis (e.g., the x-axis) in the same direction (e.g., +x or −x), and the optical coupling of the received light to the optical waveguide can be reduced by about 5% or less or about 10% or less. In some embodiments, there can be at least one other position (i.e., a second position different from the input position) on at least one of the optical ferrule and the cradle that does not substantially move when the temperature of the optical assembly changes (e.g., a reference position that can be a center of thermal expansion of either the optical ferrule or the cradle, or both).

[0016] According to some aspects of the present disclosure, an optical assembly includes an optical ferrule assembly and a cradle. In some embodiments, the optical ferrule assembly may include an optical ferrule having a mounting region and a light redirecting side (e.g., a reflective surface arranged to reflect light from a first direction toward a second direction), and an optical waveguide (e.g., an optical fiber) secured to the mounting region. In some embodiments, the optical ferrule of the optical ferrule assembly is secured within the cradle. In some embodiments, when an input light beam enters the optical ferrule through an input position and optically couples to the optical waveguide after being redirected by the light redirecting side, a temperature change in the optical ferrule assembly may cause the input light beam and the input position to move, and the input light beam may continue to enter the optical ferrule through the input position, but the reference position of the optical assembly does not move. In some embodiments, the reference position may be a center of thermal expansion of the optical ferrule and / or the cradle. In some embodiments, the optical assembly may also include an optical component configured to emit the input light beam. In some embodiments, the cradle may be configured to align the optical ferrule and the optical component. In some embodiments, the optical component may be, but is not limited to, a PIC, a lens, a prism, a grating, a sensor, or a VCSEL.

[0017] Referring now to the drawings, FIG. 1 is a perspective view of an optical assembly according to the present disclosure. The optical assembly 200 includes an optical ferrule 10 and a mating cradle 60 for securing the optical ferrule 10 and aligning the optical ferrule 10 with an optical component (not shown in FIG. 1 but discussed elsewhere herein). In some embodiments, the optical ferrule 10 includes a mounting region 13 to which one or more optical waveguides 40 may be attached. For example, one optical ferrule may be attached to 8, 12, or 16 optical waveguides 40, or any other suitable number. In some embodiments, the number of optical waveguides 40 may match the number of corresponding optical waveguides in the optical component (e.g., waveguides in a photonic integrated circuit, or PIC). In some embodiments, the mounting region 13 may include grooves or channels into which individual optical waveguides 40 (e.g., individual optical fibers) may be inserted and / or held in place. In some embodiments, the optical ferrule 10 may also include a light redirecting side 14 that includes a reflective surface (e.g., a mirror) that redirects an incident light ray (e.g., light traveling through and exiting the optical waveguide 40) in a different, second direction (e.g., downward toward optical components mounted on a substrate below the cradle, not shown in FIG. 1).

[0018] FIG. 2 is a perspective view of an optical ferrule assembly, such as the optical ferrule assembly shown in the optical assembly of FIG. 1. FIG. 3 is an alternative perspective view of the optical ferrule assembly, showing the optical ferrule from another angle. For the following discussion, FIGS. 2 and 3 can be considered side by side. In some embodiments, an optical ferrule assembly 80 can include an optical ferrule 10 including a mounting region 13 and a light redirecting side 14. One or more light guides (e.g., optical fibers) 40 can be mounted in the mounting region 13. In some embodiments, the light redirecting side 14 can be an angled reflective surface on the interior of the optical ferrule. Light exiting the light guides 40 and traveling through the optical ferrule 10 can strike the reflective surface of the light redirecting side 14 and be redirected by reflection in a second direction (a direction different from the direction from which it exited the light guides 40). In some embodiments, the second direction can be angled such that light is redirected from the light redirecting side 14 through a cradle 60 (see FIG. 1) and to an optical component mounted below the cradle 60 (see FIG. 4). 1 , when the optical ferrule assembly 80 is mated with and secured by the cradle 60, the optical ferrule 10 is substantially optically aligned with the optical component. In some embodiments, light may pass in either direction between the optical waveguide 40 and the optical component through an input location 11 (e.g., an input window) on the primary input face 12 of the optical ferrule 10. Light passing between the optical waveguide 40 and the optical component may be redirected by the light redirecting side 14 to create an angled optical path between the two components.

[0019] FIG. 4 is a side cutaway view of the optical assembly of FIG. 1 in optical communication with an optical component. The optical assembly 200 includes an optical ferrule 10 that may be secured within a mating cradle 60. A light beam 30 may be emitted by the optical component 70 in a first direction w1. The light beam 30 travels through an opening in the cradle 60 and strikes an input location 11 (e.g., an input window) on a major surface 12 of the optical ferrule 10. After passing through the input location 11 (and may be refracted as it passes through the input location 11), the light beam 30 strikes an optical redirecting side 14, which redirects the light beam 30 along a different second direction w2. The light beam 30 travels along direction w2 and enters an optical waveguide 40 (attached to the optical ferrule 10 at the attachment region 13). Note that the optical signal may also travel from the optical waveguide 40 back to the optical component 70 along a path opposite to the illustrated path, including a third direction w3.

[0020] In some embodiments, the optical ferrule is designed such that temperature changes in the optical assembly can cause the light beam 30 to be offset to a new path 30′, as discussed elsewhere herein. In conventional systems known in the art, this translational offset from 30 to 30′ can result in a misalignment of the input light beam 30 between the optical component 70 and the optical waveguide 40. However, as described herein, the optical ferrule 10 may be configured such that the position of the input location 11 undergoes a similar translational offset to 11′, such that the input location 11′ and the optical component 70 remain substantially aligned, and such that the input light beam 30′ strikes the translated light redirecting side 14′ and is redirected in a direction w2 and threaded into the optical waveguide 40. In some embodiments, and with respect to temperature changes in optical assembly 200, light beam 30 moves a distance d1 (to position 30') and input position 11 moves a distance d2 (to position 11') on the same axis (e.g., the x-axis as shown in FIG. 4 ) and in the same direction (e.g., the +x direction as shown in FIG. 4 ), the magnitude of d1−d2 is δ, and the maximum magnitude of d1 and d2 is at least 10 times δ. Stated differently, the magnitudes of d1 and d2 can be substantially the same, particularly over the expected operating temperature range of optical assembly 200.

[0021] In some embodiments, a second, reference position 50 on or near the major surface 12 of the optical ferrule 10 may remain substantially fixed for the same temperature change of the optical assembly 200 that causes an offset of the input light beam 30 to a position 30′ and an offset of the input window 11 to a new position 11′. In some embodiments, the reference position 50 may correspond to a center of thermal expansion of the optical ferrule 10. In some embodiments, the reference position 50 may be defined in terms of a corresponding position on the cradle 60. In some embodiments, the reference position 50 may be located on the same side of the light redirecting side 14 as the mounting area 13. In other embodiments, the reference position 50 (shown as 50′ in FIG. 4 ) may be located on the opposite side of the light redirecting side 14 from the mounting area 13.

[0022] Additionally, optical components that ferrules interface with can change in performance with temperature. For example, a waveguide grating coupler can be affected by temperature changes (e.g., increases) that cause the angle of the optical beam exiting the grating coupler to shift. Figures 5A and 5B illustrate one scenario that can occur in an optical assembly using a waveguide grating coupler as temperature changes. Figure 5A shows an optical assembly 500 including an optical ferrule 10 at a lower operating temperature. Figure 5B shows an optical assembly 500' as it would look at a higher temperature. Note that, as shown elsewhere herein, the optical ferrule 10 would typically be mated with and held aligned by a cradle, but the cradle has been removed in Figures 5A and 5B for clarity.

[0023] Returning to FIG. 5A, optical assembly 500 features grating coupler 100 connected to first waveguide 85 (e.g., the waveguide of a PIC). Collimating lens 90 is positioned to substantially collimate optical beam 30 exiting grating coupler 100, ideally aligning optical beam 30 with input location 11 on primary input face 12 on optical ferrule 10. Note that the three dashed lines (30) in FIGS. 5A and 5B can be thought of as three rays representing one optical beam, or one optical transmission between optical waveguide 40 and an optical component (e.g., first waveguide 85). Optical beam 30 passes through optical ferrule 10, is redirected by optical redirecting side 14, and enters optical waveguide 40 attached to optical ferrule 10. At the lower temperature shown in FIG. 5A, optical beam 30 is at an offset distance 110 from fixed position 50 of the optical assembly and exits optical grating 100 at angle α.

[0024] FIG. 5B illustrates the changes that occur in optical assembly 500 (becoming 500′) when a temperature change (e.g., a temperature increase) occurs. As the operating temperature of optical assembly 500 increases, the exit angle of optical beam 30 (becoming 30′) exiting grating coupler 100 can change significantly. In some embodiments, the change in angle dθg / dT (units: Kelvin (K)) with temperature change can be approximately 0.01° / K. This is due to changes in the thermal expansion of the refractive index of the waveguide material (typically silicon) and the pitch of grating coupler 100. Grating coupler 100 is typically positioned near the focal point of collimating lens 90. Therefore, a change in exit angle α′ of grating coupler 100 causes a lateral shift of optical beam 30′ exiting collimating lens 90. The amount of this lateral shift is proportional to the focal length of collimating lens 90. The angle of collimated beam 30′ has not changed significantly (compared to collimated beam 30).

[0025] To maintain efficient coupling to the optical waveguide 40, it is desirable to move the input location 11 of the optical ferrule 10 to a new location 11' to match the lateral shift of the optical beam 30'. In some embodiments, this can be achieved using the thermal expansion of the material of the optical ferrule 10. In some embodiments, the optical ferrule 10 (and cradle, not shown) can be designed to hold a reference location 50 (e.g., the center of the expansion point of the optical ferrule 10) in a fixed position (e.g., relative to the cradle). The input location 11 (see FIG. 5A) can be offset from the reference location 50 by a distance 110 calculated to achieve the required temperature-dependent movement of the light-redirecting side 14 (to location 14'). If the offset 110 is L, then the thermal expansion of the additional offset (110') is L'-L = L*CTE*ΔT, where CTE is the thermal expansion coefficient of the optical ferrule 10. Therefore, the total offset 110 + 110' should be approximately L = f(dθg / dT) / CTE.

[0026] In other words, optical ferrule 10 is configured such that its thermal expansion causes input location 11 to shift to input location 11' and light redirecting side 14 to shift to light redirecting side 14'. Light beam 30' now passes through input location 11', is redirected by light redirecting side 14', and remains substantially aligned with optical waveguide 40.

[0027] Terms such as "about" will be understood by those of ordinary skill in the art in the context in which they are used and described herein. Where the use of "about" as applied to quantities expressing feature sizes, amounts, and physical characteristics is not otherwise clear to those of ordinary skill in the art in the context in which it is used and described herein, "about" will be understood to mean within 10 percent of a particular value. A quantity given as about a particular value may be exactly that particular value. For example, where it is not otherwise clear to those of ordinary skill in the art in the context in which it is used and described herein, an amount having a value of about 1 means that the amount has a value between 0.9 and 1.1, and may be 1.

[0028] Terms such as "substantially" will be understood by those skilled in the art in the context in which they are used and described herein. Unless otherwise apparent to those skilled in the art in the context in which they are used and described in this specification, the term "substantially equal" means approximately equal, with "about" being as defined above. Unless otherwise apparent to those skilled in the art in the context in which they are used and described herein, the term "substantially parallel" means within 30 degrees of parallel. Directions or surfaces described as substantially parallel to one another may, in some embodiments, be within 20 degrees, or within 10 degrees, of parallel, or may be parallel or nominally parallel. Unless otherwise apparent to those skilled in the art in the context in which they are used and described in this specification, the term "substantially aligned" means aligned within 20% of the width of the objects being aligned. Objects described as being substantially aligned may, in some embodiments, be aligned within 10% or within 5% of the width of the objects being aligned.

[0029] All of the above-referenced references, patents, or patent applications are hereby incorporated by reference in their entirety. In the event of any inconsistency or contradiction between the incorporated reference portions and this application, the information in the foregoing description shall prevail.

[0030] Descriptions of elements in a figure should be understood to apply equally to corresponding elements in other figures unless otherwise indicated. While specific embodiments have been illustrated and described herein, those skilled in the art will recognize that the specific embodiments illustrated and described may be replaced by various alternative and / or equivalent embodiments without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Accordingly, the present disclosure is intended to be limited only by the claims and equivalents thereof. The following are exemplary embodiments. [Item 1] an optical assembly comprising an optical ferrule configured to receive an input light beam through an input location on a major input face of the ferrule along a first direction for coupling to an optical waveguide secured to the ferrule, the ferrule including a reference location, wherein a temperature change of the optical assembly causes the input light beam and the input location to move a distance d1, d2, respectively, along the same axis and in the same direction, rather than to the reference location; The magnitude of d1-d2 is δ, An optical assembly, wherein the maximum value of the magnitudes of d1 and d2 is greater than 10δ. [Item 2] an operating temperature range, wherein the temperature change of the optical assembly across the operating temperature range causes the input light beam and the input position, but not the reference position, to move distances d1 and d2, respectively, along the same axis and in the same direction; The magnitude of d1-d2 is δ, Item 2. The optical assembly according to item 1, wherein the maximum value of the magnitudes of d1 and d2 is greater than 10δ. [Item 3] 3. The optical assembly according to item 2, wherein the operating temperature range of the optical assembly is from about -40°C to about 100°C. [Item 4] a temperature change of at least 10 degrees of the optical assembly causes the input light beam and the input position, but not the reference position, to move distances d1 and d2, respectively, along the same axis and in the same direction; The magnitude of d1-d2 is δ, Item 2. The optical assembly according to item 1, wherein the maximum value of the magnitudes of d1 and d2 is greater than 10δ. [Item 5] Item 2. The optical assembly of item 1, wherein the reference position is within about 10 microns of a major surface of the optical ferrule. [Item 6] Item 6. The optical assembly of item 5, wherein the main surface is the main input surface. [Item 7] Item 10. The optical assembly of item 1, wherein the optical ferrule is configured to receive the input light beam along the first direction and redirect the received light along a different second direction. [Item 8] Item 1, the optical assembly, wherein the optical ferrule is configured to receive the input light beam from an optical component. [Item 9] Item 9. The optical assembly of item 8, wherein the optical components include one or more of a photonic integrated circuit, a lens, a prism, a grating, a sensor, and a vertical cavity surface emitting laser. [Item 10] Item 1. The optical assembly of item 1, wherein the temperature change of the optical assembly causes the input light beam and the input position to move away from the reference position. [Item 11] Item 10. The optical assembly of item 1, wherein the optical ferrule comprises a mounting region for securing one or more optical waveguides, and a light redirecting side for receiving light along a first direction from an optical waveguide secured to the mounting region and redirecting the received light along a different second direction. [Item 12] Item 2. The optical assembly of item 1, wherein the reference position and the mounting area are positioned on the same side with respect to the light redirecting side. [Item 13] Item 1, wherein the reference position and the mounting area are positioned opposite each other with respect to the light redirecting side. [Item 14] Item 1, the optical assembly further comprising a cradle configured to secure the optical ferrule therein and align the optical ferrule with respect to an optical component. [Item 15] Item 15. The optical assembly of item 14, wherein the optical component comprises one or more of a photonic integrated circuit, a lens, a prism, an optical slab, a grating, a sensor, and a vertical cavity surface emitting laser. [Item 16] Item 15. The optical assembly of item 14, wherein the cradle defines the reference position for an optical ferrule. [Item 17] Item 15. The optical assembly of item 14, wherein the thermal expansion coefficient of the cradle is at least 10 times smaller than the thermal expansion coefficient of the optical ferrule. [Item 18] Item 15. The optical assembly of item 14, wherein a temperature change of the optical component causes the input beam to move and a temperature change of the optical ferrule causes the input position to move. [Item 19] an optical ferrule having an optical waveguide fixed to the optical ferrule; an optical component; and an optical assembly comprising: the optical ferrule is configured to receive light from the optical component and couple the received light to the optical waveguide; and aligning the optical ferrule with respect to the optical component to optimize optical coupling of the received light to the optical waveguide when the optical ferrule and the optical component are at temperature T1; reducing the optical coupling of the received light into the optical waveguide by at least 10% by moving the received light a first distance while maintaining the temperature of the optical ferrule and the optical component at T1; changing the temperature of the optical ferrule and the optical components from T1 to move the received light the first distance, thereby reducing the optical coupling of the received light to the optical waveguide by less than about 10%. [Item 20] 20. The optical assembly of claim 19, wherein the optical waveguide is an optical fiber comprising a core having a diameter of about 5 to 15 microns. [Item 21] an optical ferrule having an optical waveguide fixed to the optical ferrule; an optical component, the optical ferrule configured to receive light from the optical component through an input location of the optical ferrule and optically couple the received light to the optical waveguide; and a cradle that secures the optical ferrule therein and aligns the optical ferrule with respect to the optical component, wherein when the temperature of the optical assembly changes, the received light and the input position each move in the same direction along the same axis, and the optical coupling of the received light to the optical waveguide is reduced by approximately 10% or less. [Item 22] Item 22. The optical assembly of item 21, wherein at least a second position of at least one of the optical ferrule and the cradle does not move when the temperature of the optical assembly changes. [Item 23] an optical ferrule including a mounting region and a light redirecting side, the optical ferrule having an optical waveguide secured to the mounting region; a cradle in which the optical ferrule is fixed; an optical ferrule assembly comprising: an optical assembly, wherein when an input light beam enters the optical ferrule through an input position of the optical ferrule and is optically coupled to the optical waveguide after being redirected by the light redirecting side, a change in temperature of the optical ferrule assembly causes the input light beam and the input position to move such that the input light beam continues to enter the optical ferrule through the input position, but the reference position of the optical assembly does not move. [Item 24] Item 24. The optical assembly of item 23, further comprising an optical component configured to emit the input light beam, wherein the cradle is configured to align the optical ferrule and the optical component. [Item 25] Item 25. The optical assembly of item 24, wherein the optical components include one or more of a photonic integrated circuit, a lens, a prism, a grating, a sensor, and a vertical cavity surface emitting laser.

Claims

1. an optical assembly comprising an optical ferrule configured to receive an input light beam through an input location on a major input face of the ferrule along a first direction for coupling to an optical waveguide secured to the ferrule, the ferrule including a reference location, wherein a temperature change of the optical assembly causes the input light beam and the input location to move a distance d1, d2, respectively, along the same axis and in the same direction, rather than to the reference location; The magnitude of d1-d2 is δ, The maximum value of the magnitude of d1 and d2 is greater than 10δ, An optical assembly in which, based on temperature changes within an operating temperature range of the optical assembly, thermal expansion of the optical ferrule causes the input position to displace relative to the reference position, and this displacement compensates for a shift in the direction of the axis of the input light beam.

2. 10. The optical assembly of claim 1, wherein the operating temperature range of the optical assembly is from about -40°C to about 100°C.

3. a temperature change of at least 10 degrees of the optical assembly causes the input light beam and the input position, but not the reference position, to move distances d1 and d2, respectively, along the same axis and in the same direction; The magnitude of d1-d2 is δ, The optical assembly of claim 1 , wherein the maximum value of the magnitudes of d1 and d2 is greater than 10δ.

4. The optical assembly of claim 1 , wherein the reference position is within about 10 microns of a major surface of the optical ferrule.

5. The optical assembly of claim 4 , wherein the major surface is the primary input surface.

6. 10. The optical assembly of claim 1, wherein the optical ferrule comprises a reflective surface that receives the input light beam along the first direction and reflects the received light along a different second direction.

7. The optical assembly of claim 1 , wherein the optical ferrule is configured to receive the input light beam from an optical component.

8. The optical assembly of claim 7 , wherein the optical component comprises one or more of a photonic integrated circuit, a lens, a prism, a grating, a sensor, and a vertical cavity surface emitting laser.

9. The optical assembly of claim 1 , wherein the temperature change of the optical assembly causes the input light beam and the input position to move away from the reference position.

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