CN1493013A - optical module - Google Patents

Abstract

An optical module (12) for an optical device (10) is provided. The module (12) includes an optical element (14) and a relative reference base (18). The optical element (14) is spatially fixed relative to a registration device (50). The registration device (50) is configured to be connected to the fixed reference base (20).

Description

optical module

technical field

The invention relates to an optical element for manufacturing an optical device. More precisely, the invention relates to an optical module carrying optical, opto-electrical or optomechanical components.

Background technique

Optical devices are increasingly used in a variety of industries and technologies to provide high-speed data transmission, such as in fiber optic communications equipment. Convert to or incorporate optical devices in a variety of applications that previously used only electronics. Optical devices typically include multiple components that must be precisely mounted and aligned for the device to operate and function effectively. Example components include optical fibers, waveguides, lasers, modulators, detectors, gratings, optical amplifiers, lenses, mirrors, prisms, viewing windows, and the like.

Historically, optical devices (such as those used in fiber optic communications, data storage and retrieval, optical inspection, etc.) have shared little in common in terms of packaging and installation methods. Because of such differences in the design of these devices, this limits the application of automation equipment for automatic production of these devices. In order to automate the high-volume production of such equipment, each individual production line element has to be specially designed.

In contrast, industries such as printed circuit board manufacturing and semiconductor manufacturing have evolved to have common design rules and packaging methods. This allows the same part of automation equipment to be used in multiple designs. Taking printed circuits as an example, multiple applications ranging from computer motherboards to mobile phones can be designed from relatively the same set of basic standard parts. These modules include printed circuit boards, integrated circuit chips, discrete capacitors, and more. Furthermore, the same automated equipment (such as pick and place machines) is suitable for the assembly of each of these designs because they use common components and design rules.

Further complications arise in the automated assembly of optical devices. Such assembly is complicated because of the precise mechanical alignment requirements of the optical elements. This adds to the problems that arise due to design changes. These problems arise from the fact that many properties of the optical components cannot be economically controlled to precise tolerances. Examples of these properties include the concentricity of the core relative to the cladding, the position of the optical axis of the lens relative to the external mechanical dimensions, the back focus position of the lens, the spectral characteristics of thin film interference filters, etc. Even if the mechanical mounting of each optical element is such that each element is in the exact theoretical design position, due to the tolerances listed above, the performance specifications of the optical device will not be met.

To understand the precise alignment requirements for high-performance optical devices, consider the simple example of aligning two single-form optical fibers. In this instance, the following mechanical alignments are required to ensure adequate optical coupling from one fiber to another: fiber angle to each other, fiber facet angle, lateral alignment (perpendicular to the direction of light propagation), and longitudinal distance (parallel to the direction of light propagation). direction of propagation).

A typical single form optical fiber for telecommunications in the 1.3 μm to 1.6 μm wavelength band has an effective core diameter of about 9 μm and an outer cladding size of 125 μm. Typical tolerances for concentricity of the core to the outer diameter of the cladding are 1 micron. If the outer claddings of the two fibers are perfectly aligned and have no angular or longitudinal errors, the cores may still have 2 microns of lateral error. This error will produce a theoretical coupling loss of about 14% or 0.65dB. This loss is unacceptable in many applications. Techniques using "active alignment" (such as that described in U.S. Patent No. 5,745,624, entitled "Automatic Alignment and Latching Method and Apparatus for Fabrication of Fiber Optic Modules," issued April 28, 1998 Day authorization) can improve the coupling efficiency.

Contents of the invention

In one example aspect, an optical module for an optical device is provided. The module includes an optical element and a relative reference base configured to connect to a fixed reference base. The bonding material fixedly couples the optical element with respect to the relative reference base. This fixes the position and orientation of the optical element relative to the registration feature relative to the reference mount. In one aspect, welding is used to fix the component in a spatial position relative to the relative reference base.

Description of drawings

Figure 1 is a perspective view of an optical device according to one embodiment of the present invention;

Figure 2A is an exploded perspective view of the optical module shown in Figure 1;

Figure 2B is a bottom plan view of the component base;

3 is a front plan view of the optical module of FIG. 1;

4 is a bottom plan view of the optical module of FIG. 1;

Figure 5 is a top plan view of the fixed datum base shown in Figure 1;

6 is a cross-sectional view of the optical module of FIG. 4 taken along line 6-6;

7A is a cross-sectional view of a registration device for registering relative reference bases using the fixed reference base shown in FIG. 1;

Figure 7B is an anatomical cross-sectional view of a registration device;

Figure 8A is a perspective view illustrating an adhesive material used in the present invention;

Figure 8B is a side cross-sectional view illustrating the bonding material of Figure 8A;

Figure 8C is an enlarged view of the bonding material;

Figure 8D is an enlarged view of the bonded material illustrating deformation of the material after heating;

Figure 9 is a perspective view illustrating an optical module of the present invention including a gradient index (GRIN) lens;

Figure 10 is a front plan view of the optical module in Figure 9;

11 and 12 are side views illustrating electrical connections to optical modules;

Figure 13 illustrates thermal dissipation techniques for optical modules;

Figures 14, 15 and 16 are views of another embodiment of the fiber holder.

Detailed ways

The present invention encompasses aspects that reduce or eliminate many of the problems associated with the aforementioned techniques. The invention provides an optical element which is pre-aligned in a standardized optical module. The optical module can be aligned with sub-micron precision relative to the registration device. The registration device on the optical module can be aligned with the matching device on the base. This is similar to mounting electronic components in or on a printed circuit board. Optical devices can be easily fabricated by mounting pre-aligned optical modules on an optical "circuit board". Pre-calibration of optical components can compensate for deviations between components, thereby virtually eliminating the effects of component variability. Pre-aligned optical modules are also well suited for automated fabrication of devices. Modules can be fabricated in silicon using well known silicon processing techniques. However, any suitable material may be used. Preferred materials are those currently used for electrical or optical components. Furthermore, the invention can be used on active devices such as lasers, modulators, detectors, and the like. Electrical conductors can be fabricated on multiple layers for coupling with active optical elements. Circuits including analog and digital circuits can also be fabricated directly on the module or on a fixed reference base.

In one aspect, the present invention provides an optical module in which an optical component is mounted to an optical component mount. The optic mount is secured to a relative reference mount (eg, a substrate mounting plate with a desired position and orientation). In one aspect, soldering is used to mount the components. The relative reference mount is attached to a fixed reference mount, such as a base, to maintain the optical element in a desired position and orientation relative to the fixed reference mount. In this typical configuration, the optical elements are pre-aligned to a desired spatial reference and orientation by adjusting the optical element mount relative to the reference mount before fixing the relative positions of the optical elements. This can be used to provide common element pre-alignment while compensating for misalignments that occur between optical elements. The following description cites many specific examples, however, in many respects the invention is not limited to the particular configurations, elements or techniques herein.

FIG. 1 is a perspective view of an optical device 10 . For purposes of illustrating the present invention, the optical device 10 acts as a simple optical fiber to optical fiber coupler. However, the invention can be used with more complex or other optical devices and other types of optical elements.

In FIG. 1 , optical device 10 is fabricated from two optical modules 12A and 12B that include respective optical elements 14A and 14B, described in this particular example as optical fibers. This fiber is mounted to respective optic mounts 16A and 16B, which are positioned and oriented to achieve the desired position and orientation of optics 14A and 14B relative to substrate mounting plates 18A and 18B, respectively. Specific examples of such coupling are set forth in more detail below, however, other aspects of the invention are not limited to such examples. In the example illustration specifically set forth in FIG. 1 , substrate mounting plates 18A and 18B comprise generally planar backing plates. The substrate mounting plates 18A, 18B are one example of relative reference bases. The relative reference base can have any shape or configuration. Substrate mounting plates 18A and 18B are mounted to fiducial mount 20 to bring optical elements 14A and 14B into substantial alignment. Base 20 is one example of a fixed reference base, and any suitable fixed reference base of suitable shape and configuration can be used.

The optical element modules of the present invention can be pre-assembled and pre-aligned to a suitable datum so that the final optical device can be fabricated by simply mounting the assembled optical module on a datum base. In the example of FIG. 1 , reference base 20 is illustrated as a planar base that can be considered an optical "circuit board" that receives optical modules to form optical, opto-electrical or optical -Equipment.

FIG. 2A is an exploded perspective view of the optical module 12 . In the particular example shown in FIG. 2A , optical element mount or holder 16 includes an upper element mount or holder 24 and a lower element mount or holder 26 . Also other configurations are within the scope of the invention. FIG. 2A illustrates an example mounting technique for attaching optics mount 16 to substrate mounting plate 18. As shown in FIG. In this example, bonding material 30 is delivered to the top surface of substrate mounting plate 18 . Material 30 preferably has at least two states. In one state, material 30 does not interfere with or contact base 16 . The optics mount 16 can then be positioned relative to the substrate mounting plate 18 with up to 6 degrees of freedom. In another state, the material joins bases 16 and 18, thereby fixing their relative position therebetween. In a preferred embodiment, material 30 comprises a thermally or chemically responsive (or active) material, such as solder or other joining material. Solder can include any type of solder in solder pads, solder balls, solder, solder bumps, and the like. Including those types of solders used for lip-soldering wafer electronic components. However, other materials such as dry adhesives react chemically, or are activated by other means or can use other adhesion techniques. Preferably, the adhesion technique is such that there is some relative movement between the optics mount 16 and substrate mounting plate 18 before they are fixedly adhered. In embodiments where a thermally activated material is used, a heating element (see FIG. 8B for details) may be provided to heat the material 30 . For example, in FIG. 2A a heating element is provided which is activated by application of electrical energy to the contact pads 34 . This can be achieved by electrically contacting pad 34 and applying an electrical current. However, other heating techniques may also be used. Of course, other techniques of changing the state of the bonding material can also be used, such as the application of curing elements (radiation or chemicals). Any suitable adhesive including brazing, welding, bonding or other techniques can be used. Activated adhesives can be used including exposure to air, heat, chemicals, heating radiation including light or UV.

2B is a bottom plan view of optics mount 16 and lower mount 26 illustrating bond pads 40 arranged to mate with material 30 shown in FIG. 2A. The liner 40 may comprise, for example, metal placed on the lower base 26 . In another embodiment, an adhesive pad 40 including an integrated heating element and electrical contact pads to activate the heating element is also provided. A reduction in bonding time can be obtained by heating the bonding pad 40 and bonding material 30 .

FIG. 3 is a front plan view illustrating optical microcomponent 12 of optical component mount 16 adjacent to substrate mounting plate 18 . In the arrangement illustrated in FIG. 3 , material 30 is not initially in contact with optics mount 16 . As described below, material 30 can be activated to fill or secure gap 32 between base 16 and base 18 . However, other types of material 30 may be used where there is actual contact between bases 16 and 18 or where material 30 fills gap 32 prior to bonding. In a preferred embodiment, before the base 16 is fixedly bonded to the base 18, both elements can be manipulated up to six degrees of freedom, as shown in FIG. 3 along the X and Y axes. The other axis Z is shown in , and both are perpendicular to the plane of the figure, rotating around the three axes. For some optics, proper alignment of all six degrees of freedom may not be required and fewer degrees of freedom can be provided. In one aspect, material 30 includes solder. FIG. 3 also illustrates an example registration device 50 . In the example implementation of FIG. 3, each registration feature 50 is a protrusion configured to mate with reference mount 20, as described below.

FIG. 3 also illustrates component registration features 60 formed in the lower base 26 and component registration features 62 formed in the upper component base 24. As shown in FIG. In general, any registration technique can be used, and the invention is not limited to the specific examples described here. In this example implementation, component registration features 60 and 62 include V-shaped grooves configured to receive an optical component (eg, optical component 14 ). The optical element 14 can be connected to the optical element base by adhesive or solder, for example. Optical element 14 is preferably fixed to element mount 16 to maintain alignment relative to registration device 50 relative to reference mount 18 .

4 is a bottom plan view of optical module 12 illustrating substrate mounting plate 18 and a portion of lower optics mount 26 of optics mount 16 . Pad 54 on substrate mounting plate 18 may be bonded with adhesive material 72 . The bottom plan view of FIG. 4 illustrates the interface surface 64 of the optics mount 16 . Interface surface 64 is the input, output, or input/output face of optical element 14 in FIG. 3 . In some embodiments, the interface surfaces of adjacent optical modules are in adjacent contact. In some embodiments, a refractive index optically matching material fills any gaps between adjacent interfaces to provide improved connectivity and reduce reflections. For example, the optically matching material may be in solid, gel or liquid form. In one embodiment, interface surface 64 is a plane that forms an angle with respect to a plane perpendicular to the direction of propagation of optical fiber 14 . For example, this angle might be 8 degrees. The angled surface 64 of the optical element 14 is preferred because it reduces the amount of reflected light that is coupled back into the fiber optic. If two modules are in proximity or in adjacent contact, adjacent optic mounts will have the appropriate angle. In embodiments where angles or specific interface finishes are desired, interface surface 64 can be shaped or fabricated using a suitable process (eg, lapping, chemical machining, machining, etc.). Or use additional processes to achieve the desired configuration. For example, after the optic 14 is secured within the optic mount 14, the surfaces 64 can overlap to achieve a desired angle or surface finish. This technique can also be used to ensure that the surface of the optical element is flush with interface surface 64 . In some embodiments, however, it may be desirable to have the optical element 14 either recess or protrude from the interface surface 64 .

FIG. 5 is a top plan view of a reference mount 20 configured to receive optical modules 12A and 12B as shown in FIG. 1 . Registration devices 70A and 70B are provided to receive registration devices 50 on respective optical modules 12A and 12B. In an example implementation, the recesses of the features 70 are precisely determined to match the protrusions of the registration device 50 shown in FIGS. 3 or 4 . This example implementation is described in more detail in Figure 7A. The dotted outlines indicate the arrangement of the substrate mounting boards 18A and 18B. This configuration provides a kinematic-type registration or alignment technique. An example kinematic technique is described in US Patent 5,748,827 entitled "Two-Stage Kinematic Base". Any suitable reference or calibration technique may be used, however, preferably the reference technique should be accurate and provide high repeatability. In this example embodiment, a thermally activated material 72 (eg, solder) is provided that can be heated to fixedly bond the optical module to the reference mount. In such embodiments, the contact pads 74 are electrically connected to a heater that is used to heat the material 72 . Material 72 is preferably aligned with liner 54 shown in FIG. 4 . For example, liner 54 may be a material to which material 72 will adhere strongly. For example, pad 54 can comprise a metal to which the solder will adhere. The pads used to promote adhesion can have multiple layers. For example, one layer bonded to the adhesive material and another layer bonded to the base, such as the base 16, 18 or the base 20, on the other hand, the adhesive pad 54 on the substrate mounting plate 18 may also include Heating elements are integrated and electrical contact pads may be provided to activate these heating elements. A reduction in bonding time can be obtained by heating the bonding pad and bonding material 72 .

FIG. 6 is a cross-sectional view illustrating the mounted optical module 12 taken along line 6 - 6 in FIG. 4 and including the base 20 . This figure illustrates an assembled configuration in which the optical module 12 is attached to the reference mount 20 and the component holder 16 is attached to the substrate mounting plate 18 .

FIG. 7A is an enlarged cross-sectional view, and FIG. 7B is an enlarged anatomical view illustrating the V-groove registration device 70 and the protruding registration device 50. Referring to FIG. The relative spacing between the plate 18 and the base 20 can be controlled by adjusting the angle or width of the V-groove 70 or the wall of the protrusion 50 . If monocrystalline silicon is fabricated in the proper orientation, the material is typically held in place by the material's crystal structure, and the width can be adjusted to control the pitch. The connection between the plate 18 and the base 20 actually takes place at the line contact point 76 .

8A is a perspective view illustrating the bonding material 30 in more detail, and FIG. 8B is a cross-sectional view illustrating the bonding material between the lower element base 26 and the mounting plate 18 . The bonding material 30 is fed onto a heating element 80 which is electrically connected to a conductor 82 . Heating element 80 may comprise a resistive element such as a refractory metal or an alloy such as tantalum, chromium, or nichrome, and is configured to melt material 30 when sufficient electrical current is supplied through conductor 82 .

The cross-sectional view shown in FIG. 8B illustrates the configuration in the vicinity of the heating element 80 . FIG. 8B is a pattern of thin film layers and is without scale and only illustrates devices, such as contacts 34 , away from heater element 80 and near the edge of mounting board 18 . Element 80 is electrically connected to contact 34 via electrical conductor 82 . An electrically insulating layer 87 may optionally be placed between element 80 and material 30 to increase the amount of electrical current flowing through element 80 . Additional layers or layers 85 may be deposited on insulator 87 to promote adhesion or provide other desired characteristics or qualities. This is known in metal deposition as "under-bump metallurgy" or UBM technique. A thermal (and/or electrical) insulating layer 89 can also be applied to reduce the transfer of thermal energy to surrounding components. Preferably, the heating element 80 is designed to operate adiabatically. As electrical current flows through the heating element 80 and the heating element begins to warm, thermal energy flows into the bonding material 30 . Similarly, the structure is preferably configured to reduce heat flow into the surrounding area. This reduces the energy required to activate the bonding material, reduces heating and assembly time, and reduces thermal stress on surrounding materials. Element 80 can have any suitable shape, including rectilinear, bifilar, serpentine, and the like. Solder provides a bonding material that is able to bond quickly (in less than 100 seconds) and allows the bond to be "reworked" by reheating the solder.

A variety of materials can be selected in order to obtain the desired suitable physical properties. _SiO2 provides good thermal and electrical insulation and is easy to process. Of course, other materials including other oxides or organic thin films may also be used. Electrically insulating layer 87 is preferably relatively thin and provides high thermal conductivity. Silicon nitride is an example material. Conductor 82 may be any conductive material, however, preferred materials include those that are readily deposited, such as thick refractory metals, gold or aluminum. The material used for liner 54 may be any material suitable for adhering to adhesive material 30 . Examples include gold, nickel, platinum, and the like. The thickness of the various layers should also be chosen to reduce the heat load on the reheat element. Pad 40 is shown with layers 40A and 40B. Layer 40A may be a material suitable for bonding to thermally insulating layer 89 . For example, if layer 89 is _SiO2 then it is a Ti layer. 40B is configured to bond with bonding material 30 and may be, for example, gold, nickel, platinum, or other material. The pad 40 can have a thin film structure of multiple layers of titanium, nickel and gold. Titanium is used as an adhesion layer to the silicon. Second, nickel is deposited on top of the titanium to allow the solder to have a strong intermetallic bond with the nickel. Finally, gold is deposited on top of the nickel to prevent corrosion of the nickel. Other acceptable buffer metallurgy or UBM (under bump metallurgy) configurations may also be used depending on the solder alloy and many other considerations. The pads may also be pre-tinned with a thin layer of solder to form an intermetallic with under bump metallurgy prior to securing the component.

In another aspect, component holders can be used for laser welding to secure components. The solder is melted by the laser and adheres to the sloped surface provided on the component. The laser welding operation on both sides of the fixing element is preferably carried out simultaneously by means of two or more laser sources. Laser energy can be delivered by optical fiber.

As shown in FIG. 8C , in one embodiment, material 30 includes a solder formed with a large surface area region 84 and a tapered region 86 . As material 30 is melted, surface tension causes liquid material to flow from tapered region 86 to large surface area region 84 and causes large surface area region 84 to expand bottomwise and upwardly as shown in FIG. 8D. This configuration is advantageous because it allows the orientation of the component mount 16 to be optimally adjusted (through the six degrees of freedom discussed with respect to FIG. 3 ) without any interference from the adhesive material 30 . The bonding material contacts only two surfaces when heat is applied and the material fills between the two elements. Similarly, for mounting the substrate mounting plate 18 on the datum base 20, the plate 18 can be safely aligned within the part 70 prior to application of the adhesive material 72 or activation of the heating element. This solder flow technique is described in US Patent 5,892,179, entitled "Solder Bumps and Structures for Integrated Redistribution Path Conductors," issued April 6, 1999. It is also possible to use multiple tapered regions 86 as regions where it is desirable to increase the volume of solder flowing towards the large surface area region 84 .

Alternatively, the component base can be fixed to the substrate mounting board by laser welding. The component base and reference plate may be provided with external sloped surfaces with suitable solder bond metallurgy. The solder melts with the laser and adheres to the sloped surfaces provided on the component base and the substrate mounting plate. The laser welding operation on both sides of the fixing element is preferably carried out simultaneously by means of two or more laser sources. Laser energy may be delivered through an optical fiber. Laser welding can also be used to secure the substrate mounting plate to the fixed reference plate.

As noted above, other bonding techniques including adhesives and UV treatment techniques may be used, and the invention is not limited to solder. On the one hand, however, bonding techniques can conveniently use the surface tension that develops in the bonding materials. Note that the solder or adhesive is electrically conductive to provide electrical contact to the optical device between multiple layers or adjacent circuits. Thermally conductive materials can be used to help dissipate the heat. On the other hand, two bonding materials are used, which can be the same or different and can be used simultaneously or sequentially. For example, after the solder is applied, a second bonding material can fill the gap to provide additional stability. However, shrinkage or other shape changes of the bonding material should be addressed to maintain calibration. In some embodiments, roughness or texturizing the surface by any suitable technique can be used to enhance the adhesion of the bonding material.

Element 14 may be any type of optical opto-electrical or opto-mechanical element including active or active elements. In the examples above, the optical element 14 is shown as an optical fiber. To illustrate an alternative example optical module 12, an optical element 90 comprising a GRIN lens is shown in Figs. 9 and 10 . FIG. 9 is a perspective view illustrating a lens 90 secured in the component mount 16 attached to the substrate mounting plate 18 . Fig. 10 is a front plan view. The lens 90 is registered with the registration groove 60 . Additional support bonding material 92 is provided to secure the lens 90 to the component mount 16 . This could be adhesive, solder or other bonding material.

The various elements can be fabricated from any suitable technique or material. In one embodiment, the depressions or grooves of the various registration devices are formed by anisotropic etching of single crystal silicon. The protrusions can be made in a similar suitable manner. This configuration should preferably eliminate or substantially reduce motion in any of the six degrees of freedom. This requires achieving sub-micron pitch reproducibility between elements. For example, the [100] orientation of single crystal silicon allows the formation of such devices that can be oriented at 90 degrees to each other. Any suitable etching or forming technique may be used. A common anisotropic etch uses KOH and masking to define the desired device. Any suitable sputtering, plating, evaporation or other fabrication techniques can be used contemplating a variety of conductive layers, heating element layers and insulating layers.

Aspects of the invention described above provide pre-calibrated optical modules that reduce or eliminate the effects of component variability. In the above example, this is achieved by adjusting the base of the element (the holder) relative to the registration features on the substrate mounting plate. The adhesive material fixes the spatial orientation between the element and the registration device. Precise registration features are provided on the substrate mounting plate 18 to enable it to be plugged into an optical "circuit board" to manufacture devices comprising multiple optical element modules. Optical modules are suitable for automatic assembly of optical devices because they are pre-aligned as standardized standard parts and can be easily mounted on reference mounts. Optical modules can be manually placed into an optical "circuit board" or the process can be automated. This particular optical module is preferably standardized to facilitate such automation. Furthermore, this configuration allows for assembly of the device in a "top donward" form in which the optical module is moved down to the optical "circuit board" which "Making process automation easier. Additionally, because the different modules are fabricated using similar materials, changes in thermal expansion will affect all modules in a similar manner, so that alignment between adjacent modules on the optical "circuit board" is maintained.

The electrical conductivity of the solder bond may conveniently be used to provide electrical connections to electrical components on the module. The solder can be heated in any order or combination, including simultaneously. The location and sequence of solder heating can be determined to reduce or compensate for distortion within the component, including thermal distortion. Solder can also be used conveniently, since being able to reheat the solder allows for component repositioning, removing, replacement and/or repair.

Figure 11 is a simplified block diagram of another aspect of the invention. In FIG. 11 , electrical circuitry 120 is electrically connected to optics mount 16 . Circuit 120 may be any type of circuit (eg, an integrated circuit). In such embodiments, optical element 14 is typically a sensor or an active element electrically connected to circuitry 120 . Electrical pads 122 and 124 are mounted on base 20 . Electrical pads 126 are mounted on base 16 , and electrical connections 128 are then provided between pads 124 and pads 126 . FIG. 12 is a cross-sectional view of another embodiment in which electrical connections 130 are mounted through holes extending through substrate mounting plate 18 . In this embodiment, bonding material 30 provides an electrical connection between electrical connection 130 and optics mount 16 . Pad 124 extends such that it contacts bonding material 72 , thereby providing electrical connection to circuit 120 . Optional circuit 136 is also illustrated in FIG. 12 . Circuitry 136 is mounted on base 16 and can be electrically connected to other circuits using the proposed conductor path technique. The various electrical connections in the conductors can be deposited using deposition techniques, such as thin film techniques. When an adhesive material is used to provide the electrical connection, the adhesive material should be electrically conductive.

Figure 13 is a side view of another aspect of the invention illustrating techniques for heat dissipation that can be produced by active optical devices. Thermally conductive underfill 140 is provided between base 16 and substrate mounting plate 18 and between substrate mounting plate 18 and base 20 . Underfill 140 is a thermally conductive material that allows heat generated by device 14 to be transferred to base 20 where the thermal energy is dissipated across a relatively large area of base 20 . By reducing heat buildup, thermally generated deformation is reduced and the life of device 14 is increased. Heat sinks can be mounted to the base 20 to further aid in heat dissipation. In one embodiment, heat sink 142 includes a thermoelectric cooler configured to transfer thermal energy away from base 20 . In one embodiment, the thermoelectric cooler is integrated with the base. In another example embodiment, the fins 142 include a series of channels configured to carry liquid cooling fluid. In addition, the heat sink 142 can optionally be connected to the optics mount 16 directly or through an unstressed thermal path such as copper, gold, aluminum or silver strips. Heat spreading (thermal spreading) films or layers can be adhered directly to thermally active devices or various multiple components.

FIG. 14 illustrates an exploded perspective view of the component holder 216 . The fiber end 215 allows the protective buffer to be removed, leaving only the fiber cladding and core. Likewise, the fiber end 219 has the protective buffer removed, leaving only the fiber cladding and core. In one embodiment of the fiber of the fiber coupling device 210, the tip of the fiber end 215 is cleaved at an angle to reduce the amount of light reflected from the tip of the fiber end 215 into the fiber 214. Depending on the application, the tips of the fiber ends 215 and 219 may also be split, polished or prepared in various other ways, such as forming a lens on the tip.

FIG. 15 illustrates a perspective view of bottom holder 226 without optical fiber 214 and top 218 . The V-groove 234 is patterned to accept the end of an optical fiber with the protective buffer stripped away. V-groove 236 is slightly larger than V-groove 234 and is patterned to accept the fiber section with the protective buffer. V-grooves 234 and 236 are preferably formed by anisotropic etching in the [100] crystallographic direction of silicon. Adhesive baffles 238, 240, 242 and 244 are shown in Figure 15 and are shown as V-shaped grooves. Adhesive baffles 238 , 240 , 242 , and 244 collect excess adhesive that is present after bonding top fixture 224 to bottom fixture 226 . Otherwise, any excess adhesive may extrude from the sides and edges of the component holder 216 .

16 illustrates a perspective view of the bottom holder with optical fiber 214 and top 218 positioned within V-shaped groove 236. FIG. Fiber ends 215 and 219 are placed within V-groove 234 . A protective buffer layer 217 is also visible in this figure. The V-groove 236 provides strain relief for the fiber and top 218 so the fiber does not break at the fiber ends 215 and 219 where the protective buffer layer 217 has been removed. Top holder 224 has a V-groove configuration similar to bottom holder 226 so that when they mate to form component holder 216, fiber 214 and top 218 are tightly captured, or "sandwiched." One of the fibers can be used in the calibration process. The configuration with three grooves 234 provides a symmetrical mirror image between the elements.

In a general aspect, the present invention provides an optical module in which optical changes due to component variability are eliminated or greatly reduced. This provides consistency in multiple optical modules, which is particularly ideal for automated assembly. In one aspect, the invention can be viewed as providing three stages of alignment between the optic and the optic mount. The first stage of alignment is provided between the element mount (holder) and the optical element, eg with V-groove registration as shown or other techniques. The second stage of calibration is between the optics mount and the registration device relative to the reference mount. This also eliminates or reduces calibration variations due to component variability. The final alignment takes place between the optical module and the reference mount. In another aspect, the optical element has an optical characteristic that varies spatially with respect to at least one dimension. The optical element is aligned with the reference structure on the relative reference base by fixing the position of the component base relative to the registration device of the relative reference base, thereby aligning the optical characteristics. In one aspect, the first stage of alignment is eliminated, the optics are aligned directly with the registration device relative to the reference mount, and the mount/holder is not used.

While the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and content without departing from the spirit and scope of the invention. For example, the amount of solder, heaters and receptors can vary depending on specific requirements. The order of reflowing the solder can be varied to increase stability. The optical elements may be any type of active or passive optical, opto-electrical or opto-mechanical elements and are not limited to the specific examples presented here. The optical element can be aligned and its orientation fixed in any suitable or desired manner. The specific elements and examples presented herein are provided to illustrate various aspects of the invention and do not limit the scope of the invention. Other elements, shapes, components, configurations, etc. are within the scope of the invention. Any suitable material can be used for the different elements. In one specific aspect, the relative reference base and other elements are fabricated from a single crystal material such as silicon. On the other hand, these elements can be made from any electrical material including semiconductors or ceramics. Other materials include machinable materials (eg, steel, aluminum, metal alloys, etc.) depending on the requirements of the particular tool. Optical devices can be fabricated using assembled optical modules by "pick and place" machines or any suitable or desirable method. In such embodiments, a chamfer or bevel on the edge of the base of the element can facilitate mechanical gripping of the base. Similarly, the various elements of the invention can be fabricated using any desired technique. Solders are known in the art and any suitable solder can be selected to obtain the desired properties. Soldering may be performed in an atmosphere that prevents or removes oxidation of the solder. The optical element can be connected directly to the relative reference mount without a separate element mount. As used herein, "light" is not necessarily visible light. Furthermore, the optical element may be any active or passive optical, opto-electrical or opto-mechanical element. The optical modules can be pre-calibrated using any suitable technique. In an alternative example, calibration is performed after the optical module or relative reference mount has been mounted to the optical "circuit board".

Claims (81)

1. An optical module used on an optical device, comprising: Optical element; a relative reference base having registration features configured to connect to the reference base; and An adhesive material configured to secure the optical element relative to the registration feature relative to the reference mount. 2. The optical module of claim 1, comprising an optical element mount configured to be fixedly connected to the optical element. 3. The optical module according to claim 1, wherein the bonding material comprises solder. 4. The optical module according to claim 1, wherein the bonding material is electrically conductive. 5. The optical module according to claim 2, wherein the optical element base comprises first and second plates between which the optical element is fixed. 6. The optical module of claim 1 , wherein the optical element has an optical characteristic that varies with respect to at least one dimension, and wherein the optical characteristic is calibrated relative to a reference, the reference relative to registration with respect to the reference base Device OK. 7. The optical module according to claim 1, wherein the bonding material comprises an adhesive. 8. The optical module of claim 1, wherein the bonding material provides a fixed spatial orientation between the optical element and the relative reference mount. 9. The optical module according to claim 8, wherein the bonding material has a first state in which the spatial orientation can be adjusted and a second state in which the spatial orientation is fixed. Towards. 10. The optical module of claim 9, wherein the adhesive material is operably attached to only one of the optical element and the relative reference mount when in the first state. 11. The optical module of claim 10, wherein the adhesive material is activated to fill the gap. 12. The optical module of claim 11, wherein application or removal of heat causes a change in state of the bonding material. 13. The optical module of claim 11, wherein application or removal of radiation causes a change in state of the bonding material. 14. The optical module of claim 1, wherein the relative reference base is substantially planar. 15. The optical module of claim 1, wherein the reference base comprises a substantially planar base. 16. The optical module of claim 1, wherein the bonding material has a first state in which the optical element is movable with a maximum of six degrees of freedom relative to the relative reference mount. 17. The optical module of claim 2, comprising an adhesive pad between the optical element mount and the opposing reference mount configured to adhere to an adhesive material. 18. The optical module of claim 2, wherein the optical element includes a registration device configured to register the optical element. 19. The optical module of claim 2, wherein the optical element is bonded to the optical element mount. 20. The optical module of claim 1, wherein the bonding material is thermally activated and at least one heater element is thermally coupled to the bonding material. 21. The optical module of claim 2, comprising a heater element mounted on at least one of the relative reference mount and the optical element mount. 22. The optical module of claim 21, comprising electrical conductors mounted on at least one of the relative reference mount and the optics mount, the optics mount being electrically connected to the heater element. 23. An optical module according to claim 22, comprising contact pads electrically connected to the electrical conductors. 24. The optical module of claim 1, comprising an adhesive pad on the opposing reference mount configured to adhere to an adhesive material, the adhesive material being attached to the reference mount. 25. The optical module of claim 1, wherein the relative reference mount comprises silicon. 26. The optical module of claim 2, wherein the relative reference mount comprises silicon. 27. The optical module of claim 2, wherein the optical element mount includes an interface surface and the optical element is flush with the interface surface. 28. The optical module of claim 1, wherein the relative reference mount comprises a semiconductor. 29. The optical module of claim 1, wherein the relative reference mount comprises ceramic. 30. The optical module of claim 1, wherein the registration feature is configured to provide substantial motion registration to the fixed reference mount. 31. The optical module of claim 1, comprising electrical connections to the optical element. 32. The optical module of claim 31, wherein the electrical connections are made through vias. 33. The optical module of claim 1, wherein the optical element is an active device and the optical module includes means for dissipating heat from the active device. 34. The optical module of claim 1 including a fiber optic tail from the optical element for pre-alignment from the optical element to the registration device. 35. Optical modules for optical devices, comprising: Optical element; a generally planar base plate attached to the optical element; A generally planar opposing reference base configured to connect to the generally planar fixed reference base is bonded to the element base plate by an adhesive material. 36. The optical module of claim 35, wherein the bonding material comprises solder. 37. The optical module of claim 35, comprising an optical element mount coupled to the optical element. 38. The optical module of claim 35 , wherein the optical element has an optical property that varies with respect to at least one dimension, and wherein the optical property is calibrated to a reference, the reference relative to a registration of a relative reference base determined by the device. 39. The optical module of claim 35, wherein the bonding material comprises an adhesive. 40. The optical module of claim 35, wherein the bonding material provides a fixed spatial orientation between the optical element and the relative reference mount. 41. The optical module according to claim 35, wherein the adhesive material has a first state in which the spatial orientation can be adjusted and a second state in which the spatial orientation is fixed. 42. The optical module of claim 41, wherein the bonding material contacts only one of the optical element mount and the relative reference mount in the first state. 43. The optical module of claim 42, wherein application or removal of heat causes a change in state of the bonding material. 44. The optical module of claim 35, comprising an adhesive pad between the optical element mount and the opposing reference mount configured to adhere to an adhesive material. 45. The optical module of claim 35, wherein the bonding material is heat activated and the at least one heating element is thermally connected to the bonding material. 46. The optical module of claim 35, wherein the relative reference mount comprises silicon. 47. The optical module of claim 38, wherein the registration feature is configured to provide substantial motion registration to the fixed reference base. 48. The optical module of claim 35, comprising electrical connections to the optical element. 49. The optical module of claim 48, wherein the electrical connections are made through vias. 50. The optical module of claim 35, wherein the optical element is an active device and the optical module includes means for dissipating heat from the active device. 51. The optical module of claim 35 including a fiber optic tail from the optical element for pre-alignment from the optical element to the registration device. 52. An optical module used in an optical device, comprising: Optical element; an optical element mount configured to be tightly coupled to the optical element; a relative reference base configured to be attached to the reference base; and The fixed spatial orientation between the base of the optic and the base of the relative reference. 53. The optical module of claim 52, comprising an adhesive material that fixes the relative spatial position. 54. The optical module of claim 53, wherein the bonding material comprises solder. 55. The optical module of claim 54, wherein the optical element has an optical property that varies with respect to at least one dimension, and wherein the optical property is calibrated to a reference, the reference relative to a registration of a relative reference base determined by the device. 56. The optical module of claim 55, wherein the registration feature is configured to provide substantially motion registration to the fixed reference base. 57. The optical module of claim 54, wherein the adhesive material has a first state in which the spatial orientation can be adjusted and a second state in which the spatial orientation is fixed. 58. The optical module of claim 53, wherein the bonding material contacts only one of the optical element mount and the relative reference mount in the first state. 59. The optical module of claim 58, wherein the bonding material is activated to fix the spatial orientation. 60. The optical module of claim 59, wherein application or removal of heat causes a change in state of the bonding material. 61. The optical module of claim 52, wherein the relative reference base is substantially planar. 62. The optical module of claim 52, comprising an adhesive pad between the optical element mount and the opposing reference mount configured to adhere to an adhesive material. 63. The optical module of claim 60, comprising a heating element disposed on at least one of the relative reference mount and the optical element mount. 64. The optical module of claim 52, wherein the optical element mount comprises silicon. 65. The optical module of claim 52, comprising electrical connections to the optical element. 66. The optical module of claim 65, wherein the electrical connections are made through vias. 67. The optical module of claim 52, wherein the optical element is an active device and the optical module includes means for dissipating heat from the active device. 68. The optical module of claim 52 including a fiber optic tail from the optical element for pre-alignment from the optical element to the registration device. 69. An optical module used in an optical device, comprising: Optical element; a relative reference base having registration features configured to connect to the reference base; and An adhesive material configured to securely secure the optical element in orientation and position relative to the registration feature relative to the reference mount. 70. The optical module of claim 69, wherein the bonding material comprises solder. 71. The optical module of claim 69, wherein the optical element has an optical property that varies with respect to at least one dimension, and wherein the optical property is calibrated to a reference, the reference relative to a registration of a relative reference base determined by the device. 72. The optical module of claim 69, wherein the bonding material provides a fixed spatial orientation between the optical element and the relative reference mount. 73. The optical module of claim 72, wherein the bonding material has a first state in which the spatial orientation can be adjusted and a second state in which the spatial orientation is fixed. 74. The optical module of claim 73, wherein in the first state the adhesive material is operably attached to only one of the optical element mount and the relative reference mount. 75. The optical module of claim 74, wherein application or removal of heat causes a change in state of the bonding material. 76. The optical module of claim 69, wherein the bonding material is thermally activated and the at least one heater element is thermally connected to the bonding material. 77. The optical module of claim 69, comprising an optical element mount configured to couple the optical element to a relative reference mount. 78. The optical module of claim 69, comprising electrical connections to the optical element. 79. The optical module of claim 78, wherein the electrical connections are made through vias. 80. The optical module of claim 69, wherein the optical element is an active device and the optical module includes means for dissipating heat from the active device. 81. The optical module of claim 69 including a fiber optic tail from the optical element for pre-alignment from the optical element to the registration device.

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