WO2003079087A1

WO2003079087A1 - Optical module and method of fabricating same

Info

Publication number: WO2003079087A1
Application number: PCT/US2002/019540
Authority: WO
Inventors: Michael J. Brunolli; Andrew J. Piloto
Original assignee: Nurlogic Design, Inc.
Priority date: 2002-03-14
Filing date: 2002-06-20
Publication date: 2003-09-25

Abstract

An optical module (200) used in fiber optic networking, and a method for manufacturing such an optical module, incorporates optoelectronic devices (210), image guide technology including optical fibers (204), high speed electronics (208), and integrated electronic packaging. In one realization, both the opto-electronic devices and the high-speed electronic devices are assembled into the module. The base of the module consists of an image guide (202) which has optical fibers embedded into it. The opto-electronic devices are 'flipchip-ed' onto the image guide within the module in such a manner as to eliminate the need for active alignment. The electronic devices are assembled into the optical module in close proximity with the optoelectronic devices in order to preserve wideband signal integrity. These devices are assembled with conventional flipchip and/or wirebond technology. Accordingly, the present invention eliminates the need for active alignment while simultaneously addressing the need for an optimal optical and electrical path. This in turn reduces the overall cost of the module assembly.

Description

OPTICAL MODULE AND METHOD OF FABRICATING SAME

FIELD OF THE INVENTION

This invention relates generally to optical communications, and more particularly, to an opto-electronic/high speed electronic package and packaging method that enables high speed, mixed signal integration in a low cost fashion.

BACKGROUND OF THE INVENTION As demand increases for high bandwidth in router, server and cluster applications, so does the need for simple, scalable high speed interconnection links, and particularly optical interconnections. See, for example, Karstensen, H., Wieland, J., Dal'Ara, R., and Blaser, M., "Parallel Optical Link for Multichannel Interconnections at Gigbit rate", Optical Engineering, Vol. 37 No. 12, December 1998.

Bit synchronous fiber-ribbon based, parallel optical point-to-point links are ideally suited for such high bandwidth applications. See, for example, Kartensen, H., Hanke, C, Honsberg, M. Kropp, J. Wieland, J., Blaser, M, Weger, P., and Popp, J., "Parallel Optical Interconnect Modules with Multifiber Connectors", Proc. 44^th ECTC, pp. 324-329, Washington, DC (1994). Ishak, W., et.al., "Optical Interconnects-The POLO Approach", Optoelectronic Interconnects III, Proc SPIE 2400, 214-221 (1995), Lebby, M., et al., "Characteristics of VCSEL arrays for Parallel Optical Interconnects" Proc 46^th ECTC, pp. 279-291 (1995), Kartensen, H., et.al., "Parallel Optical Interconnection for Uncoded Data Transmission with 1 Gbps-per-channel Capacity, High Dynamic Range, and Low Power Consumption, " IEEE J. Lightwave Technol. 13(6), 1017-1030, Kartensen, H., "DC-coupled Parallel Optical Interconnect Cable with Fiber Ribbon", Proc. 43^rd ECTC, pp. 729-734, Orlando, FL (1993).

Optical modules are important components of such high bandwidth application interconnections. As referred to herein, optical modules are components used to couple between optical signals and electrical signals. Such modules may be used in short-haul applications to implement, for example, optical backplanes in routers and optical interconnects in storage area networks, and in longer-haul applications to implement, for example, add/drop multiplexers (ADMs) and fiber optic multiplexers. Optical modules can be further categorized by either "single channel" applications, where light from a single fiber optic is converted into an electrical signal, or "parallel channel" applications, where the light from either a fiber bundle or fiber ribbon is converted to the same number of electrical channels.

FIG. 1 illustrates an example of an opto-electronic path showing the use of optical modules according to a conventional approach.

As shown in FIG. 1, Very Short Reach / Short Reach (VSR/SR) in short-haul applications or SONET/ ATM for longer haul applications signals are supplied to high speed transmit electronics 102, which perform digital operations on the signals, such as framing, and then perform mixed signal (PHY) operations on the signals, such as serialization, multiplexing and clock multiplication unit (CMU) processing. The output of transmit electronics device 102 is then presented to an opto-electronic device 104, for example via RF cabling. The opto-electronic device 104 includes, for example, a laser diode driver (LDD) and vertical cavity surface emitting laser (VCSEL, currently, mostly for shorter-haul applications) or edge-emitting lasers (for SONET/ATM applications) for converting the analog electrical (PMD) signals into optical signals for transmission over an optical link 106 (e.g. optical fibers). The opto-electronic device 104 may further include modulators used to modulate the optical signal.

On the receive side of optical link 106, opto-electronic device 108 converts the received optical signals into electronic signals. Device 108 includes, for example, a photodiode (PD) and a trans- impedance amplifier / post-amp (TLA/PA). The converted electrical signals are supplied (typically, via RF cabling) to a high-speed receive electronics device 110. Device 110 can include mixed signal (PHY) electronics such as clock data recovery (CDR), demultiplexers and deserializers, as well as digital electronics such as framers. Due to the required circuit density, optical modules for parallel fiber applications typically include both opto-electronic devices and high-speed electronics for performing the above-mentioned conversions for transmitting and receiving optical signals. Accordingly, devices 102 and 104 are commonly provided in a transmit optical module 112-T, and devices 108 and 110 are commonly provided in a receive optical module 112-R. However, in many applications where a single fiber optic channel is required, the electronics and the module construction are comprised of largely "dis-integrated" electronics; that is, each functional device is separately packaged, tested and assembled into its respective electronic assembly. This is also the case with the opto-electronic device which is also separately packaged and not co-located with the front-end, high speed electronics.

Problems are encountered in the conventional approach, including the approach illustrated above. For example, and referring to FIG. 1, there are three key signal interfaces that must be considered: the high-speed electrical interface between devices 102 and 104, and between devices 108 and 110; the high-speed electrical interface between the optical and electrical components in optoelectronic devices 104 and 108; and the optical interface between devices 104 and 108 and optical link 106. During the design phase of the optical module, care must be taken to ensure the signal integrity of each of these interfaces.

Specifically, the high-speed electrical interfaces require care during design because of their tendency to exhibit RF behavior, thus requiring resolution of design issues such as radiation and impedance matching. Further, given the topological relationship between the module with additional line card circuitry coupled to the module, as well as between the module and optical fibers that receive or provide the optical signals processed by the module, either high speed electrical signaling or the optical path must be bent by 90°. Bending the high speed electrical path implicates the RF problems discussed above. Bending the optical path can require complicated and highly precise optical components to be integrated in the module.

In either case, the fiber bundle must be actively aligned with the lasers/photodetectors in the optical module; i.e., the fiber bundle must be aligned when the lasers are activated and emitting light. In the receive mode, light must be impinging upon the opto-electronic devices in order to actively align the fibers. There are several disadvantages to such active alignment: increased test time; electrical or optical loss due to non-optimal path; and increased cost.

Several attempts have been made to address the active alignment problem by providing for a passive alignment solution, as disclosed in U.S. Patent Nos. 5,499,311, 5,781,682 and 6,137,158. Generally, these conventional solutions attempt to align the fibers with the lasers/photodetectors by integrating high precision connections between the fibers and the opto-electronic devices into the package design. However, such high precision connection components are expensive to fabricate and are not entirely reliable. Accordingly, although they may be used to some benefit, further or completely different solutions must still be provided.

SUMMARY OF THE INVENTION The present invention relates to a scheme of opto-electronic/high speed electronic packaging which enables high speed, mixed signal integration in a low cost fashion.

An optical module used in fiber optic networking, and a method for manufacturing such an optical module, incorporates optoelectronic devices, image guide technology including optical fibers, high speed electronics, and integrated electronic packaging. In one realization, both the optoelectronic devices and the high-speed electronic devices are assembled into the module. The base of the module consists of an image guide which has embedded into it optical fibers. The opto-electronic devices are "flipchip-ed" onto the image guide within the module in such a manner as to eliminate the need for active alignment. The electronic devices are assembled into the optical module in close proximity in order to preserve wideband signal integrity. These devices are assembled with conventional flipchip and/or wirebond technology. Accordingly, the present invention eliminates the need for active alignment while simultaneously addressing the need for an optimal optical and electrical path. This in turn reduces the overall cost of the module assembly.

BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures, wherein:

FIG. 1 illustrates an example of an opto-electronic path showing the use of optical modules according to a conventional approach;

FIG. 2 illustrates an optical module according to an example implementation of the present invention;

FIG. 3 is a view further illustrating an optical module according to the invention taken along sectional line 3-3 in FIG. 2; FIG. 4 is a view further illustrating an optical module according to the invention taken along sectional line 4-4 in FIG. 2;

FIG. 5 further illustrates advantages in alignment between the opto-electronic devices and the optical fibers provided by the example optical module illustrated in FIG. 2;

FIGs. 6 through 12 illustrate respective steps in an example method of fabricating an optical module such as that illustrated in FIG. 2 in accordance with the invention; and

FIGs. 13 through 16 illustrate alternative topologies of an optical module in accordance with other example embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the drawings, which are provided as illustrative examples of the invention so as to enable those skilled in the art to practice the invention. Notably, the figures and examples below are not meant to limit the scope of the present invention. Moreover, where certain elements of the present invention can be partially or fully implemented using known components, only those portions of such known components that are necessary for an understanding of the present invention will be described, and detailed descriptions of other portions of such known components will be omitted so as not to obscure the invention. Further, the present invention encompasses present and future known equivalents to the known components referred to herein by way of illustration.

An example implementation of the present invention is illustrated in FIG. 2. As shown in FIG. 2, an optical module 200 includes an image guide 202 in which are embedded the terminal portions of a plurality of optical fibers 204. The image guide 202 is bonded to an integrated electronic/optical package 206. The package 206 further includes high-speed mixed signal devices 208 and opto-electronic device 210. In accordance with an aspect of the invention, opto-electronic device 210 is electrically and physically coupled to optical guide 202 via flip chip bumps 212 and corresponding pads on the surface of optical guide 202, as will be described in more detail below. Further signal and power coupling between devices 208 and 210 is provided by conductors 214, which can be, for example, wirebonds, leads, lead frames, pads, and combinations thereof.

In accordance with a further aspect of the invention, wideband signal integrity is provided by keeping conductors 214 electrically small relative to the electrical wavelength. For example, the conductor lengths are constrained to about 1/10th of the electrical wavelength or less. Signal integrity is also maintained by maintaining close proximity between the various devices 208 and 210. For example, for optical network applications operating at 2.5 Gbps (i.e. the operating frequency of the optical module), conductors 214, as well as pads and traces provided on the surface of the optical guide, are thin or thick film metallizations such as Cr/Cu/Ni/Au, having widths of about .004" and lengths not exceeding l/lO⁴ of the wavelength, with at least a .002" gap between traces. Such dimensions further minimize reflections between the optoelectronic device and high speed electronics so that any impedance introduced by the length and magnitude of parasitic elements in the traces do not adversely affect performance. It should be apparent that other types of conductors and dimensions thereof can be provided in similar and other applications, and those skilled in the art will be able to practice the invention in such applications after being taught by the present example.

FIG. 3 illustrates opto-electronic device 210 from the perspective of sectional line 3-3 taken in FIG. 2. As shown in FIG. 3, device 210 includes lasers/photodetectors 302 that operate to transmit/receive optical signals to/from fibers 204 in correspondence with electrical signals carried between lasers/photodetectors 302 and flip chip bumps 212 by signal lines 304. FIG. 4 illustrates a portion of the surface of optical guide 202 from the perspective of sectional line 4-4 taken in FIG. 2. As shown in FIG. 4, ends of fibers 204 are exposed on the surface of optical guide 202 so as to couple optical signals with corresponding lasers/photodetectors 302 in device 210. It should be apparent that the surface of optical guide 202 may further include n reflection or anti-reflective (AR) coatings and/or filters (not shown). Further provided on the surface of optical guide 202 are flip chip pads 402 by which device 210 is physically and electrically coupled to optical guide 202 via corresponding flip chip bumps 212. In this example, flip chip pads 402 are further coupled to wire bond pads 406 via leads 404 for the communication of electrical signals between device 210 and other electronic devices 208.

In accordance with an aspect of the invention, alignment to within about 12 microns between the lasers/photodetectors 302 and corresponding fibers 204 is ensured by the flip chip process that couples the device 210 to the optical guide 202. A 12 micron alignment is a highly acceptable tolerance in most common multimode applications where fibers have a diameter of 125 microns and a core 502 of either 50 microns or 62.5 microns. This aspect of the invention is further illustrated in FIG. 5. As shown in FIG. 5, 125 micron fibers 204 are arranged at a pitch of 250 microns (i.e. channel pitch). Lasers 302 such as VCSELs have an aperture size of about 15-70 microns. In one example of the invention, flip chip bumps 212 provide a clearance between chip 210 and optical guide 202 of about 25 microns. Given these dimensions of fibers 204, lasers 302 and clearance between chip 210 and optical guide 202, optical alignment between lasers 302 and corresponding fibers 204 is assured, even considering possible variations introduced by fabrication and assembly processes.

In one example, the alignment of the flip chip process is within about 5 microns and the alignment of the metallization to the fibers within the image-guide is within about 7 microns. Under these conditions, an optical alignment of the fibers to the opto-electronic devices 302 can be expected, wherein an optimal amount of the light power is coupled therebetween. It should be noted that the degree of optical alignment can be affected by many factors, such as the numerical aperture (NA) of the fiber, the types of coatings, if any, on the surface of the optical guide, and the like. Moreover, the range of acceptable coupling of light power can be dependent on many implementation factors such as the link margin. Those skilled in the art will thus recognize various ranges for an acceptable optical alignment. Further, although optical alignment is considered an advantage, the invention encompasses fabrication processes and devices that do not necessarily achieve or aim at maximum optical alignment.

It should be further noted that different degrees of fabrication tolerances may be necessary for different types of applications. For example, many single mode fibers have a core of about 5 microns, so fabrication tolerances of less than 1 micron might be necessary to provide the required optical alignment.

An example method of manufacturing an optical module in accordance with the invention will now be described in conjunction with FIGs 6 through 12.

As shown in FIG. 6, the method begins by selecting the appropriate number of fibers and arranging them with the desired pitch and dimensions. In the example illustrated in FIG. 6, using standard 50/125 or 62.5/125 micrometer multimode or single mode communications fiber, the pitch may be 250 um and the arrangement may be a l-x-4 array. However, it should be apparent that other pitch and arrangement specifications (such as 1 -x-n or m-x-n arrangements) could be selected for either the same or different types of fibers. Specifically, although a l-x-4 array is described hereinbelow for ease of illustration, two dimensional channel arrays are considered to be an advantageous application of the present invention.

Next, as in FIG. 7, the arrangement of fibers is infiltrated with a dielectric material such as glass, resin or plastic. Importantly, the dielectric material should be chosen such that it has an index of refraction greater than the fibers. A number of known techniques may be used to implement the process steps in FIGs. 6 and 7, and are within the expertise of many conventional vendors, and can also depend on the number and arrangement of fibers. It should be noted that although FIGs. 6 and 7 appear to show the infiltration step being performed at the end of the arranged group of fibers, that this is not necessary. Rather, depending on how the fibers are arranged and kept in place, the infiltration step may be performed in an intermediate portion of the group of fibers, with a surface of an image guide created by slicing the group through the dielectric material.

As shown next in FIG. 8, a surface of the image guide is planarized and polished. As can be seen, this causes a cross section of each of fibers 204 to be exposed on the surface of the image guide, thus enabling optimal optical coupling to the fibers. In one example implementation, this step results in a solid image guide 202 block of about 0.45 in.² and about 0.10 in. thickness. In a further example, the fibers extend a desired distance from the surface of the image guide opposite the planarized surface and are distally terminated in a connector such as a MT-RJ fiber connector. The extension distance and type of connector are design choices well within those skilled in the art.

It should be noted that this step may be followed by a step of coating the planarized surface of the optical guide with a film such as an AR film. Such films are usually comprised of a dielectic material such as Y₂O₃, Si0₂, BaF₂ and MgF₂, and can be selected and/or optimized on the basis of the optical wavelength used and an index of refraction of the guide/fiber as understood by those skilled in the art. Next, in FIG. 9, the planarized surface is metallized with a pattern of traces 404 and pads 402,

406 designed to carry electrical signals between the flip chip bumps of the opto-electronic device and the wirebond pads connecting to the high-speed electronic devices. Preferably, the metallization is performed using conventional thin-film techniques wherein a thin layer of metal (e.g. Cr/Cu/Ni/Au) is coated on the surface and then etched using photolithographic techniques to form the desired metallization pattern. However, it should be apparent that other techniques may be employed, such as thick film techniques. In one thin film example, the traces have a width of about .004" with at least a .002" gap between traces.

As shown in FIG. 9, and as described above in connection with FIG. 4, the metallization includes flip chip pads 402 that are designed to couple with the flip chip bumps of the optoelectronic devices, as well as wire bond pads 406. As for flip chip pads 402, by proper alignment of the pads with respect to fibers 204, and by corresponding proper alignment of flip chip bumps 212 with respect to lasers/photodetectors 302, optical alignment between the fibers 204 and lasers/photodetectors 302 can be achieved by the flip chip assembly process as mentioned above and as will be described in more detail below.

Next, as shown in FIG. 10, the opto-electronic device 210 is prepared. The opto-electronic device in one example is an integrated circuit die. This die is prepared for assembling together with the optical guide 202 using conventional flip chip solder bumping technology. For purposes of the present invention, care is taken during this step so that the flip chip bumps 212 on device 210 are properly aligned with respect to photodetectors/lasers 302 so that when device 210 is coupled to optical guide 202 via flip chip pads 402, the photodetectors/lasers are optically aligned with fibers 204. Accordingly, as shown in FIG. 11, the opto-electronic device 210 is coupled to optical guide 202 using flip chip techniques that are well understood by those skilled in the art. One example of a flip chip technique that can be performed in accordance with the invention is that provided by Unitive Electronics, Inc. As apparent from the foregoing, this step causes the photodetectors/lasers to be optically aligned with the fibers 204, and also causes the opto-electronic device 210 to be electrically coupled to pads 402 and 406 for further electrical coupling with high-speed electronic devices 208 (not shown).

Finally, as shown in FIG. 12, which is a partial cut-away view of package 206, the above- described assembly of optical guide 202 and opto-electronic device 210 is integrated in package 206, along with high-speed electronic device 208, using conventional packaging techniques such as high temperature and low temperature ceramic, PGA, SMT, TBGA, CBGA, MCM-C, MCM-D, MCM-L, thin film, multilayer thin film, etc. The opto-electronic device 210 is further electrically coupled to high-speed electronic device 208 via electrical conductors 214 and intermediate pads 1202, which can be coupling performed by conventional wirebonding techniques, for example. According to an aspect of the invention, the resulting conductors 214 are electrically small (i.e. within close proximity) and impedance matched, as discussed more fully above.

Sealing of, and the provision of I/O pins or pads in package 206 can be done in accordance with one of many known conventional packaging techniques.

It should be noted that the integration of opto-electronic device 210 and high speed electronic device 208 in package 206 is but one example of how such integration can be achieved. For example, depending on the speed of the module, the electronics are either mounted adjacent to the opto-electronic devices on the image guide or on an adjacent layer of the conventional single or multi-layer electronic package. For very high speed electronics, the electronics may also be placed on the image-guides to minimize the electrical lengths.

An example of one of many such alternative topologies is illustrated in FIG. 13. As shown in FIG. 13, the high-speed electronic devices 1302 are provided in another flip-chip package that is coupled to the opto-electronic device 210 by flip-chip bumps 1304, conductors 214, and other electrically short electrical leads (not shown).

A further alternative example is illustrated in FIG. 14. As shown in FIG. 14, one or more of the high-speed electronic devices 1402, 1406 can be provided on the surface of the optical guide 202. As shown, this can be done either by direct mounting as with device 1402, and connected with the optoelectronic device 210 and I/O using conductors 1404, or by flip-chip techniques as with device 1406, with electrical coupling provided by flip-chip bumps 1408.

A still further alternative example is illustrated in FIG. 15. As shown in FIG. 15, integrated device 1502 includes circuitry corresponding to both high-speed electronic devices 208 and opto- electronic device 210. Such degree of integration thus eliminates the need for traces and leads between such devices.

Yet another alternative example of the invention is illustrated in FIG. 16. As shown in FIG. 16, the opto-electronic device 1606 is not coupled directly to the surface of the optical guide 202'. Rather, optical guide 202' includes an etch 1604 formed therein using known techniques. The etch is preferably only several microns deeper than the width of the opto-electronic device 1606. Instead of direct alignment between the opto-electronic device 1606 and the fibers 204, optical alignment is obtained by coupling the opto-electronic device 1606 to integrated device 1602 (comprising, for example, at least high-speed electronic devices 208) via flip-chip bumps 1610, and then aligning device 1602 with optical guide 202' with flip-chip bumps 1608. Since the distances between the opto-electronics in device 1606 to the bumps 1608 can be readily and accurately determined, such opto-electronics are optically aligned with fibers 204 via the known separation between flip chip pads on the surface of optical guide 202' and fibers 204.

Although the present invention has been particularly described with reference to the preferred embodiments thereof, it should be readily apparent to those of ordinary skill in the art that changes and modifications in the form and details may be made without departing from the spirit and scope of the invention. It is intended that the appended claims include such changes and modifications.

Claims

What is claimed is:

1. An optical module, comprising: an image guide having embedded therein a portion of an optical fiber, the optical fiber having a proximal end and a distal end, the embedded portion including the proximal end of the optical fiber, the proximal end being exposed on a surface of the image guide; and an optoelectronic device coupled to the surface of the image guide in optical alignment with the proximal end of the optical fiber.

2. An optical module according to claim 1, wherein the optoelectronic device is coupled to the image guide using flip-chip techniques.

3. An optical module according to claim 1, wherein the proximal end is planarized together with the surface of the image guide.

4. An optical module according to claim 1, wherein the optoelectronic device includes flip chip bumps, and wherein the surface of the image guide includes flip chip pads, the optoelectronic device being coupled to the surface of the image guide through a coupling between the flip chip bumps and the flip chip pads.

5. An optical module according to claim 4, wherein the optical alignment between the optical fiber and the optoelectronic device is provided by a physical alignment between the flip chip bumps, the flip chip pads, and the exposed proximal end of the optical fiber.

6. An optical module according to claim 4, wherein the surface of the image guide further includes electrical leads coupled to the flip chip pads, the electrical leads providing signal communication between the optoelectronic devices and other devices.

7. An optical module according to claim 6, wherein the electrical leads are electrically short in accordance with an operating frequency of the optoelectronic device.

8. An optical module, comprising: an image guide having embedded therein respective portions of a plurality of optical fibers, the optical fibers each having a proximal end and a distal end, each respective embedded portion including the proximal end of each optical fiber, the proximal end being exposed on a surface of the image guide; and an optoelectronic device coupled to the surface of the image guide in optical alignment with the proximal ends of the optical fibers.

9. An optical module according to claim 8, wherein the plurality of optical fibers are arranged in a two-dimensional array and spaced apart from each other by a channel pitch.

10. An optical module, comprising: an image guide having embedded therein a portion of an optical fiber, the optical fiber having a proximal end and a distal end, the embedded portion including the proximal end of the optical fiber, the proximal end being exposed on a surface of the image guide; an optoelectronic device in optical alignment with the proximal end of the optical fiber; and flip-chip means for coupling the optoelectronic device to the surface of the image guide.

11. An optical module, comprising: an image guide having embedded therein a portion of an optical fiber, the optical fiber having a proximal end and a distal end, the embedded portion including the proximal end of the optical fiber, the proximal end being exposed on a surface of the image guide; an optoelectronic device in optical alignment with the proximal end of the optical fiber; a high-speed electronic device; first means for coupling the optoelectronic device to the high-speed electronic device; and second means for coupling the high-speed electronic device to the surface of the image guide, the first and second means together providing the optical alignment.

12. An optical module according to claim 11, wherein the second means includes flip-chip bumps and corresponding flip-chip pads.

13. An optical module according to claim 11, wherein the first and second means include flip- chip bumps and corresponding flip-chip pads.

14. An optical module according to claim 11, wherein the image guide has an etch formed in the surface, the etch having an area and depth corresponding to the optoelectronic device.

15. A method of fabricating an optical module, comprising: preparing an image guide, including: embedding therein a portion of an optical fiber, the optical fiber having a proximal end and a distal end, the embedded portion including the proximal end of the optical fiber, and exposing the proximal end on a surface of the image guide; and coupling an optoelectronic device to the surface of the image guide so as to optically align the optoelectronic device with the proximal end of the optical fiber.

16. A method according to claim 15, wherein the coupling step includes providing flip chip pads on the surface of the image guide and corresponding flip chip bumps on the optoelectronic device.

17. A method according to claim 16, wherein the coupling step further includes controlling a physical alignment between the flip chip pads and the exposed proximal end of the optical fiber.

18. A method according to claim 16, wherein the coupling step further includes controlling a physical alignment between the flip chip bumps and one of a laser and a photodiode in the optoelectronic device.

19. A method according to claim 17, wherein the coupling step further includes controlling a second physical alignment between the flip chip bumps and one of a laser and a photodiode in the optoelectronic device.

20. A method according to claim 15, wherein the preparing step further includes planarizing the surface of the optical guide.

21. A method according to claim 16, further comprising: providing electrical leads on the surface of the optical guide coupled to the flip chip pads, the electrical leads providing signal communication between the optoelectronic device and other devices.

22. A method according to claim 21, wherein the providing step includes controlling a length of the electrical leads in accordance with an operating frequency of the optoelectronic device.