The present invention relates to a packaging system for optical and optoelectronic devices, more particularly, to a packaging system for connecting optical fibers to each other or for connecting optical fibers to an electrical converter, and even more particularly to a micromachined plug and socket apparatus that uses V-grooves to passively align optical fibers to each other, or optical fibers to an electrical converter.
Conventional optical fiber to electrical converters require active alignment techniques. Similarly, conventional optical fiber to optical fiber connections also require active alignment techniques. Conventional methods of connecting optical fibers, or optical fibers to an electrical converter, require a skilled laborer to manually align the optical fibers together, or to manually align the optical fiber to an electrical converter. For example, first, the skilled laborer must manually move the optical fiber into position. Next, the skilled laborer must perform a test to determine if an acceptable response is achieved based on the position of the optical fiber. If the response is not acceptable, the skilled laborer must reposition the optical fiber and perform another test to determine if an acceptable response is achieved based on the repositioning. This process must be repeated until an acceptable response is achieved. Once an acceptable signal has been achieved, the position of the optical fiber in relation to the electrical converter must be fixed by applying an adhesive. Further, the position of the optical fiber in relation to the electrical converter must be maintained until the adhesive sets or hardens. This adhesive can expand or contract with temperature, moving the fiber out of alignment with the second fiber or electrical converter. This process of active alignment is very time consuming and cost inefficient. In addition, the requirement of skilled labor to align the optical fiber to the electrical converter prohibits end users from attaching and reattaching the optical fibers, or the optical fiber to the electrical converter, without the expertise of a skilled laborer. For example, connecting and disconnecting fibers requires a time-consuming fiber splicing procedure every time the module needs to be disconnected and reconnected. Further, the final assembly of the optical fiber to the electrical converter is limited to individual skilled laborers experienced in attaching the optical fibers to electrical converters and prohibits the delegation of the assembly of these components to other non-skilled laborers. Alternatively, it is known to use machines to position the optical fiber; however, even if machines are used, active testing is still required to verify that the signal achieved is acceptable. As with manual positioning of the optical fiber, if the signal achieved is unacceptable, the machine must reposition the fiber and perform another test to determine if the signal is acceptable. This process is repeated until an acceptable signal is achieved. The position of the optical fiber is then fixed using an adhesive.
A conventional butterfly package is shown in
However, because of the need to use a housing to encapsulate the discrete devices, conventional butterfly packages suffer from increased size and weight. In addition, the conventional butterfly packages require extended assembly and prototyping time, thereby increasing manufacturing costs. The ability to rework, repair, or upgrade modules is not possible using the conventional approach and therefore long term total cost of ownership is also high.
It is therefore an object of this invention to provide a packaging system for optical and optoelectronic devices for connecting optical fibers to each other or for connecting optical fibers to an electrical converter.
It is therefore another object of the present invention to eliminate the need for costly active alignment of fiber to fiber and fiber to electrical connections in the manufacturing process for optical and optoelectronic modules.
It is a further object of the present invention to provide a micromachined plug and socket apparatus that uses V-grooves to passively align optical fibers to each other, or optical fibers to an electrical converter to greatly simplify the connection. For example, each socket and plug in the apparatus can have one or multiple V-grooves etched in them with fibers positioned in each V-groove.
It is therefore another object of the present invention to provide a serial connection between one set of fibers and another set of fibers by simply sliding the plug into the socket.
In particular, it is an object of the present invention to provide a high quality fiber butt joint using V-groove alignment with a plug and socket connector to precisely slide the fibers into alignment with each other.
It is another object of the present invention to provide an apparatus for connecting a plurality of optical fibers, or an optical fiber to an electrical converter, in which un-mating or disconnecting the connectors is as simple as connecting the connectors.
It is yet another object of the invention to greatly lower the cost of installing, maintaining, and troubleshooting optical distribution systems.
It is a further object of the invention to provide an apparatus for connecting a plurality of optical fibers, or an optical fiber to an electrical converter, that improves flexibility and system prototyping to greatly reduce design cycle times and therefore overall system costs.
It is yet another object of the invention to provide integrated, prepackaged optical transmitters/modulators and detectors.
It is a further object of the present invention to provide an apparatus for connecting a plurality of optical fibers, or an optical fiber to an electrical converter, where different optical and electrical modules can be connected together during system prototyping, or even in the field, to greatly lower system costs, for example, by reducing component costs, assembly complexity, design cycles, and prototyping moderations.
It is still another object of the present invention to form a two-dimensional array of optical and electrical components and stacking the two-dimensional arrays to form a highly compact three-dimensional system of optical and electrical components.
It is yet another object to the present invention to provide an apparatus for connecting a plurality of optical fibers, or an optical fiber to an electrical converter, where the optical fiber can be attached and detached from the electrical converter over and over, thereby providing a repeatable connection that provides ease of replacement, maintenance, prototyping, manufacturing, and upgrades to components with different specifications. In addition, it is an object of the present invention to provide an apparatus that permits reconfiguring both on a test bench and in the field.
It is another object of the present invention to provide an apparatus for connecting a plurality of optical fibers, or an optical fiber to an electrical converter, which can be optimized for low dispersion and low loss. Specifically, it is an object of the present invention to provide an apparatus for connecting a plurality of optical fibers, or an optical fiber to an electrical converter, that has a zero to minimum dispersion.
It is yet another object of the present invention to provide an apparatus for connecting an optical fiber to an electrical converter that is scalable to allow scaling down the device in order to push the operating frequency higher while maintaining minimal insertion loss, return loss, and group delay variation on the electrical side.
It is yet another object of the present invention to provide an apparatus for connecting a plurality of optical fibers that is scalable to allow different optical fiber cross sections to be used for different, shorter, or longer wavelength operation in addition to different optical fiber types, such as single-mode, multimode, and polarization maintaining varieties.
It is still another object of the present invention to provide an apparatus for connecting a plurality of optical fibers, or an optical fiber to an electrical converter, that is fully shielded to eliminate outside noise.
It is yet another object of the present invention to provide an apparatus for connecting optical fibers to an electrical converter that is backward compatible with industry standard butterfly packages.
It is another object of the present invention to provide an apparatus for connecting optical fibers to an electrical converter that is individually hermetically sealed to eliminate the need for butterfly packages or other environmental housings to surround and protect the optical or optoelectronic components.
It is yet another object of the present invention to provide an apparatus for connecting optical fibers to an electrical converter that is hermetically sealed by sealing the top of the packages with a soldered lid (hermetic).
It is still another object of the present invention to provide an apparatus for connecting optical fibers to an electrical converter that comprises a series of modular low footprint packages that can be plugged together, taken apart, changed around, and reconnected.
It is further object of the present invention to provide an apparatus for connecting optical fibers to an electrical converter or other fibers that distribute DC bias and signaling lines between modules, thereby eliminating the need for a butterfly package or similar industry standard housing.
It is yet another object of the present invention to provide an apparatus for connecting optical fibers to an electrical converter that decreases the size, weight, assembly time, and prototyping time, thereby reducing manufacturing costs.
Further objects, features and advantages of the invention will become apparent from the consideration of the following description and the appended claims when taken in connection with the accompanying drawings.
The above aspects of the present invention will become more apparent by describing in detail embodiments thereof with reference to the attached drawings in which:
Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention is not restricted to the following embodiments, and many variations are possible within the spirit and scope of the present invention. The embodiments of the present invention are provided in order to more completely explain the present invention to one skilled in the art.
A non-limiting embodiment of a packaging system for optical and optoelectronic devices for connecting optical fibers to each other, or for connecting an optical fiber to an electrical converter, that solves the aforementioned problems, and others, is now described with reference to
In addition, in other embodiments of the present invention, a ball lens can be passively positioned in a notch or groove between the optical fiber 4 and the optical fiber 8, for focusing the optical signal that is being transmitted between the optical fiber 4 and the optical fiber 8, to form a fiber butt joint.
Moreover, according to the present invention, assembly and disassembly of the apparatus can be repeatedly performed without having to test the apparatus for proper alignment. In addition, the un-mating or disconnecting of the plug and socket connectors according to the present invention can be performed as easily as connecting the plug and socket connectors, which greatly lowers the cost of installing, maintaining, and troubleshooting optical distribution systems.
The plug and socket packaging system of the present invention is preferably formed from silicon; however, other materials can be used for appropriate applications. In addition, in the preferred embodiment, the plug 1 and socket 2 each have an outer metal shield 16. Thus, when the plug 1 mates with the socket 2, the optical fibers 4, 8 and the interior of the package are completely encapsulated by not only the silicon plug 1 and socket 2, but also by an outer metal shield 16 and a soldered metal lid (not shown). Therefore, a fully-shielded connection within the plug/socket transition and entire packaged module is provided and outside noise or interference is minimized or eliminated.
Further, the plug and socket packaging system of the present invention preferably includes a hermetically sealed lid, such as a lid soldered over the package, or another means for hermetically sealing each individual package without requiring a butterfly package to provide external environmental protection. Therefore, the conventional butterfly package can be completely replaced by a plug and socket packaging system that is individually hermetically sealed. Alternatively, the plug and socket packaging system according to the present invention can be mounted inside a conventional butterfly package so that repair, replacement, or upgrade of modules within the butterfly package can be more efficiently performed, in comparison to conventional installed within the butterfly package.
In addition, a ball lens 10 can also be used to focus the light from the optical fiber 4 to the sensor of the photo detector 12. It is important to align the ball lens with the optical fiber 4 in order to properly focus the signal from the optical fiber 4 to the photo detector 12 or optical modulator (not shown). As shown in
In other embodiments, the plug 1 can include a corresponding V-groove or isotropically etched cavity that corresponds to the cavity or notch 14 in the socket 2 so that when the plug and socket are assembled, the opposing cavities or V-grooves hold the ball lens in place, thereby eliminating the need to use glue or epoxy. In addition, the lens is not limited to a ball lens; rather, other lens types can also be used. For example, a tubular or cylindrical lens can be used. The size and shape of the cavity 14 can be predetermined to passively align the cylindrical, or other shaped lens, with the optical fiber 4 and photodetector 12.
In the embodiment shown in
The present invention is not limited to the placement of an optical fiber in a plug and an electrical converter in a socket; rather, either a plug or a socket, according to the present invention, is capable of holding either of these devices, or a combination of these or other devices.
The present invention is not limited to plugs or sockets with only three sections. The plug 1 and socket 2 can be divided into less than or greater than three sections, depending on the application and the number of electrical connections desired. In addition, the plug 1 and socket 2 of the present invention are not limited to a hexagon-shape, and can be other shapes, for example, triangular in shape.
As shown in the non-limiting embodiment of
In order to achieve lower loss and help lower dispersion, V-grooves 33 can be formed in the surface of the plug 1 and/or socket 2, thereby removing a portion of the silicon, or dielectric, to create air gaps. This provides the designer with the ability to vary the dimensions of the V-grooves 33, thereby permitting the designer to control or design the system for desired impedance. The V-grooves 33 form air gaps which provide a variable that the designer can adjust to lower loss. In addition, the designer can use this variable to control dispersion, i.e., to reduce time delay variation versus frequency. Further, the size of the air gaps can be varied to control impedance. More specifically, the ability to control the V-groove 33 size permits the apparatus to be designed to operate single-moded. For example, as the dielectric is removed, the designer can push the “turn on” frequency of the next mode to a higher frequency, so the device will stay in a single mode and behave more predictably with less chance for mode conversion or spurious radiation.
Furthermore, as shown in
In addition, as shown in
In an example of a non-limiting embodiment of the present invention, multiple optical fibers positioned in passive alignment V-grooves interface with individual PIN diodes. The individual PIN diodes receive the optical signal from the individual optical fibers and convert the signal to an electrical signal. Next, multiple 10 Gbit/sec electrical lines are multiplexed into one 40 Gbit/sec optical line. This process of taking parallel lines of optical signals and converting them into a single serial line is known as Multiplexing (MUX). On the other hand, the process of taking a single serial line and converting it into multiple parallel lines of optical signals is known as Demultiplexing (DEMUX). Thus, for example, four 10 Gbit/sec optical signals can be combined into one 40 Gbit/sec electrical signal. Conversely, for example, four 10 Gbit/sec electrical signals can be combined into one 40 Gbit/sec optical signal. According to the present invention, one package can perform a 1:4 or 4:1 conversion. Other conversions, such as 16:1, 1:16 can also be performed by one package according to the present invention.
The present invention is not limited to RF lines, such as the center conductor and ground planes depicted in
Another advantage of the present invention is that, because the packaging system is made out of silicon, the packaging system according to the present invention has a high thermal conductivity. The thermal conductivity of the silicon packaging system is equivalent to the thermal conductivity of a packaging system made of metal. One problem with known optoelectronic modules is the requirement for high thermal conductivity in the packaging system. For example, heating of the package can cause movement of fiber alignment due to thermal expansion of dissimilar materials (for example, epoxy or solder holding fiber in place, and PIN diode material, etc.). In known packaging systems, a separate heat sink (for example, an additional component to select and attach during assembly) is located in the package to help with problems of thermal conductivity.
The packaging system according to the present invention solves these problems. First, by holding the optical fiber in a V-groove plug and socket alignment, the thermal drift of alignment is minimized. Second, the entire optoelectronic module is manufactured out of a base of silicon so it reduces the number of different materials making up the module; thus, by forming more components out of a single material, such as silicon, misalignment, which results from the use of different materials that expand at different rates with temperature variations, can be minimized or eliminated. Third, because the silicon package is functioning both as a package and as a heat sink, the high thermal conductivity of silicon maintains the overall package at a lower operating temperature for better thermal stability, provides for longer operating lifetimes, and provides a less complicated assembly.
Moreover, optoelectronic converter modules, and systems based on these modules, can be manufactured according to the present invention. For example,
Number | Date | Country | Kind |
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60262907 | Jan 2001 | US | national |
60315443 | Aug 2001 | US | national |
The present application claims priority from the co-pending U.S. Provisional Patent Application Ser. No. 60/262,907 filed Jan. 22, 2001, and provisional Patent Application Ser. No. 60/315,443 filed Aug. 28, 2001, the disclosures of which are incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US02/01510 | 1/22/2002 | WO | 11/5/2003 |