Optical sub-assembly packaging techniques that incorporate optical lenses

Techniques for manufacturing an optical transmission device in a manner so that the photonic device is protected from damage that can be caused by exposure to the environment and physical handling are described. The invention involves placing a lens or a lens array over a photonic device, either with or without the use of a receptacle device, such that the photonic device is contained within a sealed cavity. The invention has three main embodiments in which the photonic device can be hermetically sealed, quasi-hermetically sealed, or non-hermetically sealed. The optical transmission device can be configured to serve as an optical receiver, detector, or a transceiver device.

FIELD OF THE INVENTION

The present invention relates generally to optical transmission technologies, and more specifically to packaging techniques that protect photonic devices from damage.

BACKGROUND OF THE INVENTION

Optical signal transmission techniques provide the ability to transmit broad bandwidths of data across large distances. For instance, in comparison to electrical signal transmissions over copper wires, light is attenuated less in fiber than electrons traveling through copper. Therefore multiple data streams within a single optical transmission medium can be transmitted at one time. Also, the light signals travel large distances before they attenuate to a point in which regeneration of the light signals is required.

Optoelectronic devices, which are a combination of optical and electrical components, are used to build optical networks. The optical components generate, receive, and transmit light signals while the electrical components store and process the signals. Such optical components include devices such as light emitting and detecting devices, generally referred to as photonic devices, and optical fibers. Exemplary electrical components are semiconductor integrated circuit devices. Typically, photonic devices are electrically connected to semiconductor devices and the ends of optical fibers are positioned proximate to the active areas of the photonic devices. In this way, the photonic devices emit and detect light signals to and from the optical fibers and the semiconductor devices drive the photonic devices and receive signals from the photonic devices. Examples of such optoelectronic devices are described in U.S. Pat. No. 6,364,542 issued to Deane et al. and in U.S. patent application Ser. No. 10/165,553, entitled “OPTICAL SUB-ASSEMBLY FOR OPTO-ELECTRONIC MODULES,” both of which are incorporated by reference.

Although various techniques have been developed to effectively connect the optoelectronic components, improved techniques are still desirable in order to increase the transmission efficiency of optoelectronic devices and overall reliability. For instance, the optical coupling efficiency between photonic devices and optical fibers commonly requires improvement. In one specific aspect, light emitting devices tend to be biased at high voltage levels, thereby emitting light signals that have high intensity levels. These high intensity levels cause the light signals to enter the optical fibers with relatively low efficiency. Also, the durability of optoelectronic devices are commonly limited by the photonic devices, which tend to be delicate devices that are adversely affected by elements such as dust, moisture, printed circuit board mounting flux residues, cleaning residues, and harsh physical handling.

In view of the foregoing, optoelectronic manufacturing techniques to produce more efficient and reliable devices would be desirable.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to techniques for manufacturing an optical transmission device in a manner so that the photonic device is protected from damage that can be caused by exposure to the environment and physical handling. Such damage can be caused by moisture absorption, dust collection, board mounting flux residues, cleaning residues, wire bonding operations, optical fiber mounting operations, etc. The invention involves placing a lens or a lens array over a photonic device, either with or without the use of a receptacle device, such that the photonic device is contained within a sealed cavity. The invention has three main embodiments—a hermetically sealed photonic device, a quasi-hermetically sealed photonic device, and a non-hermetically sealed photonic device. The optical transmission device can be configured to serve as an optical receiver, detector, or a transceiver device.

One aspect of the invention pertains to an optical transmission device in which a photonic device is hermetically sealed within a protective cavity. This optical transmission device includes an impermeable support block having a supporting surface and a mounting surface, electrical traces, at least one photonic device attached to a respective one of the cathode pads and connected to at least one of the anode pads, a metal boundary line formed on the support surface that encircles the photonic device, and a glass lens set on top of the metal boundary line such that it is attached to the support surface of the support block.

Another aspect of the invention pertains to an optical transmission device in which a photonic device is sealed within an quasi-hermetic cavity. This optical transmission device includes an impermeable support block having a supporting surface and a mounting surface, two raised and parallel rails formed on the supporting surface and being integrally formed with the support block, the two parallel rails forming a groove that runs between each of the rails, an elastic o-ring that is set within the groove, electrical traces, a first photonic device, a receptacle that is attached to the supporting surface, the receptacle having a protruding rim that conforms to the outline of the parallel rails and which is set within the groove, the receptacle also having a first receptacle opening, and a first glass lens attached within the first receptacle opening.

Yet another aspect of the invention pertains to an optical transmission device in which a photonic device is sealed within a non-hermetic cavity. This optical transmission device includes a support block having a supporting surface and a mounting surface, electrical traces, a first photonic device, and a receptacle that is attached to the supporting surface, the receptacle securing a first glass lens such that is it positioned above the first photonic device, the receptacle also having a protruding rim that is in contact with the supporting surface, the receptacle having a receptacle cavity that fits over the photonic device whereby the photonic device is sealed between the supporting surface and the receptacle.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known operations have not been described in detail so not to unnecessarily obscure the present invention.

The present invention pertains to techniques for manufacturing an optical transmission device in a manner so that the photonic device is protected from damage resulting from exposure to the environment and physical handling. Such damage can be caused by moisture absorption, dust collection, board mounting flux residues, cleaning residues, wire bonding operations, optical fiber mounting operations, etc. The invention involves placing a lens or a lens array over a photonic device, either with or without the use of a receptacle device, such that the photonic device is contained within a sealed cavity. The invention has three main embodiments—a hermetically sealed photonic device, a quasi-hermetically sealed photonic device, and a non-hermetically sealed photonic device. The optical transmission device can be configured to serve as an optical receiver, detector, or a transceiver device.

FIG. 1illustrates one embodiment of an unassembled optoelectronic system100designed to protect photonic device106within a hermetically sealed environment. Upon assembly, optoelectronic system100can be used to convert optical signals to electronic signals and vice-versa. System100can be used to build an optical network. Optoelectronic system100is made up of the following components. First there is the optical subassembly102, which includes a support block104and a photonic device106. Photonic device106is attached to a front surface108of support block104. Secondly, there is the semiconductor device package (or the chip subassembly)110, which is a semiconductor integrated circuit (IC) device that is packaged within a protective body. The IC device within package110is electrically connected to photonic device106in order to send and receive signals from photonic device106. The IC device and photonic device106can be electrically connected by electrical traces that run along or through the body of support block104.

Thirdly there is a lens112that, when assembled, is attached to support surface108of support block104in order to protect photonic device106. Lens112is shaped like a cap or an open-ended box. Its open-end is to be placed onto the surface of support block104so that lens112covers photonic device106and seals photonic device106in a hermetically sealed environment. Then there is a receptacle114, which is to be attached to lens112. Then a ferrule116, which holds optical fibers118in place, is attached to receptacle114. After being fully assembled, optical fibers118are in optical communication with photonic device106and the optical signals that pass through fibers118get translated into electrical signals within chip subassembly110, and vice-versa.

FIG. 2illustrates a side, cross-sectional view of optoelectronic system100of FIG.1.FIG. 2provides an additional view of optoelectronic system100to facilitate a more thorough understanding of the present invention.

The main function of support block104is to support photonic device106so that optical fibers118can conveniently be set in optical communication with photonic device106. To perform this function, support block104is formed to have front surface (or supporting surface)108and a bottom surface that is attached to chip subassembly110. In one embodiment, support block106is made of an impermeable material such as a ceramic. An impermeable material prevents moisture to pass through support block104. By making support block104out of an impermeable material, it is possible to hermetically seal photonic device106within lens112. In alternative embodiments, support block104can be formed of permeable materials if it is not important to protect photonic device106from moisture absorption. For instance, support block104could be formed of plastic or FR4.

In one embodiment, lens112is made of glass because the impermeable properties of glass is used to ensure a hermetic seal of photonic device106between support surface108and lens112. Lens112can be formed of molded high-index glass material. Lens112can be either a single lenslet or an array of lenslets.

In alternative embodiments in which a hermetic sealing of photonic device106is less important, lens112can be made of optical grade plastics. This is possible when a solder reflow is not required after the lens112is attached to the ceramic support block102or the solder reflow can be carried out at relatively low temperature (lower than 220 degrees Celsius).

The cavity within lens112is referred to as a lens cavity126. Lens112can be placed over photonic device106so that photonic device106fits within lens cavity126. Rim124of lens112is rectangular shaped, however, it can have a variety of outline shapes. For example, lens112could have a rim124that has an oval outline shape instead of a rectangular shape.

In order to create a hermetic seal between support surface108and lens112, a line of metal material120is formed around the perimeter of photonic device106. Metal line120can be referred to as a metal boundary line120. A matching line of metal material122is formed around a rim124of lens112. Lens112is then attached to support surface108by placing the lines of metal120and122together and solder reflowing them together. Metal boundary line120acts as a hermetic sealing joint between lens112and support surface108such that gas and moisture cannot seep between lens112and support surface108. Alternative methods of using a metal connecting joint between support surface108and lens122can also be utilized.

In order to create a hermetic seal around photonic device106, the materials used to surround photonic device are impermeable materials. As described above, each of the lens112, support block104, and boundary lines120are formed of ceramics, metal, or glass. Materials that are not used include those that allow for seepage of moisture, such as polymers and epoxy adhesives. For instance, polymers and epoxy tend to absorb moisture or outgas and therefore introduce moisture or gas into an environment.

Interconnecting wires128connect anode pads on the surface of photonic device106to anode contact pads130on supporting surface108. Anode contact pads130are within the limits of metal boundary line120so that they will also be contained within a hermetically sealed environment when lens112is attached to support surface108. Interconnecting wires128are typically wirebonded onto photonic device106and anode contact pad130in such a way that the wires128extend outwards from photonic device and then bend back towards anode contact pads130. Lens cavity126should have a stand-off height, HSO, that is large enough to allow lens112to be placed over photonic device106without having interconnecting wires128touch the inner surface of lens112. Standoff height, HSO, is the distance between the inside surface of lens112and support surface108after lens112is attached.

By hermetically sealing photonic device106between support surface108and lens112, photonic device106is protected from the elements, such as dust and moisture. Such elements can adversely affect the operation and reliability of photonic devices. The photonic die, or arrays, will be completely sealed from the outside and no moisture will be able to diffuse into the photonic cavity. The residual moisture within the cavity will depend on the process used during sealing and on the product reliability requirements. Most hermetic packages currently follow Mil Specs of less than 5000 ppm of moisture content. Such protection provides full protection of the photonics during component handling, board assembly, and field operations.

Lens112also serves to protect photonic device106from physical damage that can be sustained during handling and use.

Lens112can also increase the coupling efficiency between optical fibers118and photonic device106. With respect to a light transmitting photonic devices, lens112can attenuate the light emitted from photonic device so that the emitted light has a smaller intensity upon entering an optical fiber. This is useful since light transmitting photonic devices are typically biased at higher than needed voltage levels in order to operate at sufficiently high data rates. In turn, this causes the emitted light to have a higher intensity level than it is needed, which causes a safety issue. Therefore, by attenuating the emitted light with lens112, a safe operation can be achieved while required data rate can be met. On the other hand, with respect to light receiving photonic devices, lens112can magnify or focus light received from optical fibers so that a higher intensity light signal can be directed into photonic device106. This can also increase the coupling efficiency between a photonic device and an optical fiber.

When optoelectronic system100supports a light detecting photonic device, it operates as a receiving device. When optoelectronic system100supports a light transmitting photonic device, it operates as a transmitter. In some embodiments, optoelectronic system100can support both a light detector and a light receiver, thereby making system100a transceiver. Optoelectronic system100can support one or more photonic devices to create a multi-channel receiver, transmitter, or transceiver. In these embodiments, a single lens112can be placed over all of the photonic devices or one lens can be placed over each photonic device. When multiple lenses are used, multiple metal boundary lines120should also be formed on support surface108and corresponding metal lines122should also be formed on the rims of each of lenses112in order to form a hermetic seal within each of the lens cavities126. When a light transmitting and a light emitting photonic device is attached to a support surface108, two types of lenses can be used. One of the lenses can be a light attenuating lens that is placed over the light emitting photonic device. Another type of lens can be a light magnifying lens that is placed over the light receiving photonic device.

Chip subassembly110, as seen inFIG. 2, includes a semiconductor die200that is mounted on top of a die attach pad202and encapsulated within a protective molding material204. Up-linking contacts206are formed on the top surface of die200in order to form an electrical pathway to connect die200with photonic device106. Interconnecting wires208connect die200to chip contact pads209, which form the contact surfaces through which optoelectronic system100can be connected to a printed circuit board or another electronic system. Chip subassembly110inFIG. 2is referred to as a leadless leadframe semiconductor chip package. However, alternative embodiments of chip subassembly110that have contact surfaces for both making contact with support block104and an external system can also be used. For instance, standard dual in-line packages, ball grid array packages, and quad-flat packages can also be used.

Chip subassembly110can have various types of contacts for connection to an electrical system such as a printed circuit board. The contacts can be flush with the side surfaces or extend past the peripheral side surfaces. In this way, the CSA can be hotbar reflowed, surface mount reflowed, pluggable. Also the CSA can have a configuration to allow for mounting onto an edge or anywhere on a printed circuit board.

Up-linking contacts206connected to contact pads210on the bottom surface of support block104. Electrically conductive adhesive or solder211can be used to secure this connection. Underfill material212is used to fill in the gaps between support block106and chip subassembly110in order to strengthen the connection between the two components.

Receptacle114attaches to lens112and forms an attachment area for ferrule116. Ferrule116is a device that secures one or more optical fibers118. As shown inFIG. 1, ferrule116secures a ribbon of optical fibers118. Receptacle114has a receptacle opening115that allows light from optical fibers118to travel through lens112in order to reach photonic device106. Receptacle114is attached to lens112by inserting lens112into the receptacle opening115. Then adhesive material132is used to secure the connection. Adhesive material can be glue since a hermetic seal between receptacle114and lens112is not critical. In the various embodiments of the invention where a lens is attached to a receptacle, the lens can be attached to the receptacle by either placing the lens within an opening of the receptacle or by attaching the rim of the opening to a front surface of the lens, as will be described in FIG.3.

Receptacle114has alignment pins117that guide ferrule116into the correct alignment with receptacle114. Correct alignment between ferule116and receptacle117ensures that optical fibers118will correctly align with photonic device106. Receptacle114can be made to have various sizes and shapes suitable for attaching a ferrule116to a lens112.

Manufacturing optoelectronic system100involves at least two separate soldering operations. First, solder is used to attach lens array112onto support surface108of support block104. Secondly, solder is used to attach optical subassembly102onto chip subassembly110. Proper selection of high-temperature solders is required to follow a manufacturing thermal hierarchy. Exemplary high-temperature solders have high lead content (e.g., 10Sn90Pb, or 5Sn95Pb, or 3Sn97Pb) with melting points greater than 300° C. In other words, manufacturing process steps should expose the optoelectronic system100to a hierarchy of decreasing temperature exposure so to not adversely affect the integrity of interfaces and components assembled in earlier steps. For instance, since lens112is attached to support surface108before optical subassembly102is attached to chip subassembly110, the melting point of the solder used between lens112and support surface108should be higher than the solder used between optical subassembly102and chip subassembly110. High-temperature solder should be used for sealing lens112to support surface108. Eutectic solder (63Sn37Pb, melting point=183° C.) can be used to connect optical subassembly102and chip subassembly110. By following this temperature hierarchy, the solder seal between lens112and support surface108can remain intact during the process of attaching optical subassembly102to chip subassembly110.

Epoxy can be used to attach components outside of the lens cavity126. For instance, epoxy can be used to attach the receptacle to the lens and the ferrule to the receptacle.

Support block104is an low temperature co-fired ceramics (LTCC) module that is formed of multiple laminated layers214of ceramic material. Metal traces216are formed between some of the adjacent ceramic layers214and conductive vias218that pass through the thickness of the layers214connect the metal traces216. The network of metal traces216and conductive vias218connect the contact pads210with the anode contact pads130and a cathode pad134on the support surface108. This network of electrical traces216and conductive vias218is convenient for maintaining a hermetic seal around photonic device106since the traces216and vias218are not exposed to the environment and therefore do not provide a pathway for moisture to seep into the lens cavity126.

FIG. 3illustrates an alternative embodiment of an optoelectronic system300wherein photonic device308is hermetically sealed. One difference between system300and system100ofFIGS. 1 and 2is that support surface302of support block304has a recessed surface cavity306and a photonic device308sits within surface cavity306. A second difference is that lens310is substantially flat. Surface cavity306is recessed to a depth such that when lens310is attached to support surface302, interconnecting wires312, which extend from the top surface of photonic device308, do not touch lens310. The depth of surface cavity306depends upon the thickness of photonic device308and the height of interconnecting wire312. The depth of surface cavity306should be set so that interconnecting wires312do not touch lens310. In some embodiments, the surface cavity306can extend through multiple ceramic layers. In some embodiments, lens310can have a cap shape as shown inFIGS. 1 and 2.

Anode contact pads314are formed on at a level that is higher than the level upon which the photonic device308is set. This allows shorter interconnecting wires312to connect photonic device308and anode contact pads314. The height at which anode contact pads314can vary depending upon design requirements.

Another difference with optoelectronic system300is that photonic device308is wirebonded to anode contact pads314that are located above, as well as below, photonic device308.

As with system100ofFIGS. 1 and 2, optoelectronic system300hermetically seals photonic device308between surface cavity306and lens310. Impermeable materials are used to form optoelectronic components immediately surrounding photonic device308. For instance, support block304can be formed of ceramic, lens310is formed of glass, and metal boundary lines316and318are used to attach lens310to support surface302via solder reflow.

Optoelectronic system300can also be formed to have multiple surface cavities306that each can contain a photonic device308. Each photonic device308can either be an optical transmitter or receiver. Each surface cavity306is also covered with a respective lens310. Each lens310can also be specially manufactured to either magnify or intensify a light signal to increase optical coupling efficiency. In some embodiments, a single lens can have a region that magnifies light while another region attenuates light signals. Each lens310is attached to support block304through metal boundary lines316to ensure the hermetic seal around surface cavity306.

FIG. 4illustrates a cross-sectional view of an optoelectronic system400according to another alternative embodiment of the present invention. In system400, multiple electrical traces402run along the supporting surface404and the bottom surface406of support block408. Electrical traces402connect cathode pad410and anode contact pads412to respective contact pads located on bottom surface406of support block408thereby facilitating the electrical connection between photonic device414and chip subassembly416. Electrical traces402are shown to be embedded within support surface404and bottom surface406. However, electrical traces402can also be formed on top of these surfaces. In order to preserve the hermetic seal within which photonic device414is contained, a layer of glass415is formed over electrical traces402. In this way, the electrical traces will not create a channel underneath lens418through which air or moisture can seep into lens cavity420. This can happen if gaps between electrical traces402and the surrounding structure of support surface404form. These gaps can be so large that metal boundary lines422and424cannot sufficiently fill in these gaps to ensure a hermetic seal. Therefore, glass layer415is formed over electrical traces402and the portion of support surface404surrounding each of electrical traces402. As shown inFIG. 4, glass layer415also covers substantially all of support surface404and bottom surface406except for the areas where conductive contact pads are located. Specifically, no glass layer is formed on support surface404where cathode pad410and anode contact pad412are formed, and no glass layer is formed on bottom surface406wherever contact pads for making contact with chip subassembly416are formed. In an alternative embodiment, glass layer415can be formed in a more limited area that includes only a region where the rim of lens418makes contact with support surface404. This glass lens formation would encircle photonic device414, cathode pad410, and anode contact pads412.

Glass layer415can be applied to support block408using various techniques such as sputtering. Again, support block408is formed of an impermeable material such as a ceramic.

FIG. 5illustrates a perspective view of a support block502and a chip subassembly504, which form an alternative embodiment of an optoelectronic system500of the present invention.FIG. 6illustrates a side cross-sectional view of optoelectronic system500in which support block502and receptacle508are shown in an unassembled arrangement. Optoelectronic system500is designed to seal photonic device506within a quasi-hermetic cavity. The packaging of system500is formed by setting receptacle508within a groove510that surrounds photonic device506. Receptacle508has an opening that secures an optical lens524. Optical lens524can be secured to receptacle508with adhesives such as an epoxy. Receptacle508and lens524combination forms a receptacle cavity526which is placed over photonic device506and thereby creates a quasi-hermetic seal over photonic device506.

A high temperature elastic o-ring512, which is set within groove510, helps seal the enclosed area surrounding photonic device506. O-ring512is loop of elastic material that conforms to the outline shape of groove510that encircles photonic device506. The enclosure around photonic device is quasi-hermetic because o-ring is typically made out of heat resistant rubber, silicone, or other polymers, which allows for the transmission of moisture. The polymers used to form o-ring512will, over time, allow some moisture to diffuse in (and out) of the enclosure to reach certain equilibrium. This equilibrium will be governed by the operating conditions of the module (e.g., power on the photonics, heat dissipated by the photonic device506, and the external environment).

Another reason why photonic device506is sealed within a quasi-hermetic enclosure is because common adhesives, such as epoxy, are used to secure lens524within receptacle508. As mentioned above, most of such adhesives tend to outgas and therefore introduce gases into the enclosure. Low outgassing polymer materials are now commercially available and the materials that cure without outgassing are being developed.

Groove510is created with the parallel set of rails516that run around the perimeter of photonic device506. Rails516are integrally formed from the material of the supporting surface518of support block502. Receptacle508has a protruding receptacle rim520that is designed to fit into groove510. O-ring512will correspondingly be compressed when rim520is set into groove510. O-ring512serves to seal the enclosed area between receptacle508and support surface518. The height, width, and separation of rails516can be adjusted depending upon the size of the o-ring and the size of receptacle rim520that is to be inserted into groove510.

Standoff stems522also extend from receptacle508. Standoff stems522make contact with support surface508and maintain a certain distance between receptacle508and support surface518. Specifically, support stems522maintain a separation distance between conductive interconnecting wires528and lens524. Interconnecting wires528tend to be fragile and are easily broken. Therefore, standoff stems522serve to protect interconnecting wires528and the connection of photonic device506to the electrical traces within support block502. Standoff stems522can be multiple individual stems or a continuous rim that extends around rim520. The shape and size of standoff stems522can vary so long as stems522serve to maintain the required separation distance between lens524and support surface518.

Standoff stems522are located outside of the receptacle rim520and therefore make contact with support surface518outside of the quasi-hermetically sealed receptacle cavity526. Standoff stems are attached to support surface518using adhesive material530. In an alternative embodiment, standoff stems522are located within the boundary created by receptacle rim520.

Receptacle508can be formed of various materials such as plastic. Support block502need not be formed of impermeable material since the system500is a quasi-hermetic packaging configuration. However, in some embodiments, support block502can be formed of a ceramic material.

In an alternative embodiment, optoelectronic system500can be manufactured so that more than one receptacle can be attached to support surface518. In this embodiment, support surface518can have multiple sets of parallel rails516and associated grooves510. In this case, support surface would likely support multiple photonic devices506, each being covered by a respective receptacle and lens combination.

In another embodiment, one receptacle has multiple openings with each opening supporting an optical lens. Each optical lens is supported over a photonic device and can be tailored to either intensify or attenuate light signals. In all embodiments of optoelectronic system500, either light emitting or receiving devices can be attached to support surface518to create an optical transmitter, receiver, or transceiver.

FIG. 10illustrates an alternative embodiment of a support block1000that is designed to seal a photonic device1002within a quasi-hermetic environment. Support block1000is different in that groove1004is set into the surface of block1000. Groove1004encircles photonic device1002such that it has a circular or ovular outline shape on the supporting surface of support block1000. Forming the inset groove1004allows protruding rails, as shown inFIGS. 5 and 6, to be optional. Actually,FIG. 10does not utilize any protruding rails to form groove1004. O-ring1006is set within groove1004and will be squashed when rim1008is inserted into groove1004. The squashed o-ring1006acts to seal the connection between groove1004and rim1008. In the embodiment ofFIG. 10, rim1008is taller than rim520ofFIGS. 5 and 6since rim1008must extend into the inset groove1004. Rim1008will also be taller than support stems1010since support stems1010make contact with the surface of support block1000.

FIG. 7illustrates a perspective view of an optoelectronic system700that encloses a photonic device702within a non-hermetic enclosure, according to one embodiment of the invention.FIG. 8illustrates a side plan, cross-sectional view of optoelectronic system700shown in FIG.7. Photonic device702is enclosed within a receptacle cavity704that is created with receptacle706and lens708. Receptacle706has an opening that secures lens708so that lens708will be secured over photonic device702. Lens708is secured to receptacle706with adhesive material709, such as epoxy. Receptacle708also has a receptacle rim710that encircles lens708. Receptacle rim710defines part of receptacle cavity704and is attached to support surface712of support block714with adhesive material716. The use of adhesive material to attach lens708to receptacle706and receptacle706to support surface712allows the possibility of the adhesive materials to outgas into receptacle cavity704. Because of this, receptacle cavity704is not completely hermetically sealed. In one embodiment, a low shrinkage, low moisture absorption and low out-gassing epoxy material is used as the adhesive agent.

Photonic device702is protected from physical damage since receptacle rim710is a solid rim that completely encircles lens708. This configuration allows photonic device702to be completely sealed within receptacle706and lens708. In an alternative embodiment, receptacle rim710can be composed of individual stems that do not enclose photonic device702within a completely enclosed receptacle cavity704.

FIG. 9illustrates a top plan, cross-sectional view of an optoelectronic system900that encloses photonic devices902and904within a non-hermetic enclosure, according to an alternative embodiment of the invention. System900includes a receptacle906that has two openings that each secure a respective optical lens908and910. Lenses908and910are secured within the openings with an adhesive agent such as epoxy. Lenses908and910can be designed to either intensify or attenuate light signals depending upon the type of photonic device that they cover. Again, photonic devices902and904can both be optical transmitters, optical receivers, or one of each.

Receptacle906is attached to supporting surface912of support block914at points surrounding each of photonic devices902and904. Receptacle906is attached to support surface912with receptacle rim916, which completely surrounds photonic devices902and904. Receptacle bar918extends between photonic devices902and904provides for additional attachment regions between receptacle906and support surface912. Receptacle bar918is a solid structure that completely separates photonic devices902and904. Receptacle rim916and bar918completely enclose photonic devices within respective enclosures and thereby protect photonic devices902and904from structural damage. Receptacle rim916and receptacle bar918are attached to support surface912with adhesive material920.

In alternative embodiments, receptacle rim916and bar918can be substituted with multiple standoff stems that are separate from each other.