Method and apparatus for communicating signals with an optical fiber

I claim:

1. An optical assembly for communication of an optical signal between an optical fiber and a receiver or transmitter, comprising

a body including a guideway;

a first semiconductor optical element for conversion between electrical and optical signals and for one of receiving and transmitting light, said semiconductor optical element mounted in register with said body;

an optical fiber having a first end, said optical fiber including a core, a cladding surrounding the core, and a protective coating deposited on said cladding;

said guideway receiving a selected length of said optical fiber, said selected length including the entire length of said fiber received by said guideway, said selected length not having been stripped of a coating deposited on said cladding; and

wherein when said selected length is received by said guideway said first end of said optical fiber is optically aligned with said optical element such that neither the location of said first end nor the location of said optical element is adjusted responsive to the measurement of the transmission of light between said optical element and said optical fiber.

2. The optical assembly of claim 1 wherein said guideway includes a V-groove.

3. The optical assembly of claim 1 wherein said guideway is defined at least in part by a wall formed by micromachining a semiconductor substrate.

4. The optical assembly of claim 1 wherein said optical element includes one of a light emitting diode and a photodetector, said core of said optical fiber being adapted for multimode propagation, and wherein said optical fiber extends from said first end to a second end that is optically aligned with a second semiconductor optical element, said length of said fiber from said first end to said second being no greater than 100 meters.

5. The optical assembly of claim 1 wherein said core of said optical fiber is adapted for the single mode propagation of light by said core.

6. The optical assembly of claim 1 wherein said protective coating is hermetic and includes silicon carbide.

7. The optical assembly of claim 1 wherein said protective coating is hermetic and has a thickness of from two to 20 monolayers of a selected molecular composition.

8. The optical assembly of claim 1 wherein protective coating is hermetic and includes one of a carbide, nitride and boride of one of silicon, aluminum and titanium.

9. The optical assembly of claim 1 wherein said body is adapted for receiving an integrated circuit and includes conductive paths for communication of signals between said optical element and said integrated circuit when received by said optical assembly.

10. The optical assembly of claim 1 wherein said body further includes a ball grid array for electromagnetic communication with said integrated circuit device.

11. The optical assembly of claim 1 wherein said protective coating is not thicker than 1 micron.

12. The optical assembly of claim 1 further comprising an optical tap including a second optical element in communication with said optical fiber.

13. An optical apparatus for communication of optical signals, comprising:

a body including a guideway;

a first semiconductor optical element for conversion between electrical and optical signals and for one of receiving and transmitting light, said semiconductor optical element mounted in register with said body;

an optical fiber, said optical fiber extending from a first end to a second end and including a core, a cladding surrounding the core, and a protective coating surrounding said cladding;

said guideway receiving a selected length of said optical fiber, said protective coating being included on said fiber for at least a majority of said selected length and said selected length including the entire length of said fiber received by said guideway;

said optical fiber, when received by said guideway, having said first end optically aligned with said optical element such that neither the location of said first end nor the location of said optical element is adjusted responsive to the measurement of the transmission of light between said optical element and said optical fiber;

a second guideway receiving a second selected length of said optical fiber, said second selected length including the entire length of said fiber received by said second guideway;

a second optical element optically aligned with said second end of said optical fiber; and

wherein said protective coating is present along all of a length of said fiber, said length including said majority of said first selected length and a majority of said second selected lengths and the entire length of said optical fiber therebetween.

14. The optical assembly of claim 13 wherein said protective coating is a hermetic coating.

15. The optical assembly of claim 13 wherein said protective coating is hermetic and includes one of a carbide, nitride and boride of one of silicon, aluminum and titanium.

16. The optical assembly of claim 13 wherein said protective coating is hermetic and is not thicker than 1 micron.

17. The optical assembly of claim 13 including an optical tap, said optical tap including a second optical element in communication with said optical fiber.

18. An optical assembly for communication of an optical signal between an optical fiber and a receiver or transmitter, comprising:

a body including a guideway having a wall;

a first semiconductor optical element for conversion between electrical and optical signals and for one of receiving and transmitting light, said semiconductor optical element mounted in register with said body;

a length of optical fiber having a first end, said optical fiber including a core, a cladding surrounding the core, and a coating deposited on the cladding and no other coating deposited over said coating for said length of said fiber, said coating having a thickness of less than about 1 micron, and said length of optical fiber having an n-factor of at least 50;

said guideway receiving a selected length of said optical fiber such that said coating contacts said wall of said guideway, said selected length including entire length of said fiber received by said guideway, said fiber including said coating thereon for at least a majority of said selected length; and

wherein said first end of said optical fiber is optically aligned with said optical element.

19. A method for communicating between an optical fiber and a transmitter or receiver, comprising:

providing a body;

providing the body with a guideway;

providing a semiconductor optical element for conversion between electrical and optical signals and for one of receiving and transmitting light;

mounting the optical element in register with the body;

providing an optical fiber having a first end, the optical fiber including a core, a cladding surrounding the core, and a hermetic coating deposited on the cladding,

placing a selected length of the optical fiber in the guideway for being received thereby and for optically aligning the first end of the fiber with the optical element, the selected length being all of that portion of the optical fiber that is received by the guideway;

refraining from stripping a coating in contact with the cladding from the selected length of the fiber; and

wherein neither the location of the first end of the optical fiber nor the location of the optical element is adjusted responsive to the measurement of the transmission of light between the optical element and the optical fiber.

20. The method of claim 19 wherein providing the body with the guideway includes providing a V-groove.

21. The method of claim 19 wherein providing the optical fiber includes providing the optical fiber wherein the hermetic coating is no thicker than 1 micron.

22. An optical apparatus, comprising:

a body including a guideway;

a semiconductor optical element mounted in register with said guideway, said semiconductor optical element for receiving or transmitting optical signals;

an optical fiber having a first end, said optical fiber including a core, a cladding surrounding the core and a protective coating;

said guideway receiving a selected length of said fiber such that said guideway contacts said coating for locating said core such that said first end is in optical alignment with said optical element; and

wherein neither the location of said first end nor the location of said optical element is adjusted responsive to the measurement of the transmission of light between said optical element and said optical fiber.

23. The optical apparatus of claim 22 wherein said coating includes one of a carbide, nitride and boride of one of silicon, aluminum and titanium.

24. The optical apparatus of claim 22 wherein said fiber has an n-factor of at least 50.

25. The optical apparatus of claim 22 wherein said selected length of fiber is not stripped of a coating.

26. The optical apparatus of claim 22 wherein said coating has a thickness of one microns or less.

Description Submit all comments and votes

FIELD OF THE INVENTION

This invention relates to optical fibers and, more particularly, to methods and apparatus for communicating optical signals between an optical fiber and a receiver or transmitter, such as a semiconductor receiver or transmitter mounted in a package.

BACKGROUND ART

Integrated circuit devices (ICs), such as microprocessors, micro controllers, and signal processors, are operating at higher and higher frequencies. For example, computer processors are currently being clocked at speeds in excess of 1 Gigahertz (GHz). At least two technological developments have contributed to this increase in operating speeds. Switching transistors, which are the building blocks of computers, now operate at lower voltages. For example, IC operating voltages have systematically dropped from 5.0 Volts to 2.2 Volts and below. Because switching power losses in transistors are proportional to the square of the operating voltage, the lower voltages reduce power dissipation, allowing higher frequency switching on the same substrate for the same total power dissipation. The second development is the use of sophisticated "radio frequency" modeling techniques for designing the layouts of conductive leads. The leads can be modeled as high frequency transmission lines, and coupling between adjacent leads as well as discontinuities, such as bends, taken into account. Such modeling has allowed the design of high-performance, multi-layered PC boards.

Unfortunately, there are disadvantages associated with such advances, such as increased sensitivity to electromagnetic interference (EMI), to voltage transients, and to common-mode noise. Desired signals can be degraded. Creative engineering and sophisticated board layouts can help reduce the deleterious effects described above. However, limits still remain. It is understood that conductive leads to high speed, low voltage ICs simply create certain problems with signal integrity and limit the speed at which signals can be propagated. For example, designers of high-speed microprocessor boards restrict communication buses emanating from the microprocessor IC to approximately 300 MHz. Multiple, parallel 300 MHz buses are used to communicate with the IC at the full bandwidth of which the IC is capable, such as 1 GHz. Each bus carries only a part of the communication with the IC. Each bus, of course, has sensitivity to EMI and other influences that reduce the integrity of the transmitted signal.

Optical fibers are known to be highly desirable for the transmission of data and other signals. Optical fibers are low cost, flexible, have a large bandwidth, and are not sensitive to EMI. However, optical fibers are not widely adopted for the communication data to and from an IC, such as the microprocessor in a personal computer.

Basically, problems associated with launching signals onto the fiber or retrieving signals off of the fiber, or, in other words, communicating with the optical fiber, limit the use of optical fibers in environments such as a personal computer, despite the advantages of fiber in terms of bandwidth, flexibility and reduced sensitivity to EMI. Many of the known techniques for communicating with an optical fiber are simply too expensive compared to other technologies, such as the use of multiple conductive 300 MHz buses.

For example, in communicating an optical signal using a fiber, optical alignment of the fiber with the transmitter or receiver with which the fiber communicates is very important, especially in higher power and/or long haul applications, to ensure that light is efficiently transferred between the receiver or transmitter and the fiber. Optical fibers have very small dimensions, and often very tight tolerances must be achieved and maintained over a range of operating parameters, such as temperature, vibration, and humidity, to provide proper optical alignment.

One approach is to terminate optical fibers in precision connectors and to mate the connectors. However, an optical connector, such as a plug connector, is typically complex and includes multiple parts, some of which can be spring loaded. The connector maintains contact between the mated fiber faces when the plug is connected with a similarly highly engineered discrete socket, or jack. Plug and jack optical connectors can also require meticulous cleaning and are subject to all manner of degradation of the face of the fiber, including degradation due to micro-cracking, and due to foreign object damage caused by triboelectric charge forces attracting and holding small particles on the end face of the fiber prior to connection. The lowest cost multimode product known today, although injection molded and known for its lowest selling price, cannot be field terminated. It must be prepared in advance to a predetermined length, and in addition, is restricted to duplex applications.

Furthermore, fibers are typically too fragile without a protective coating, or buffering, to survive in real world applications. For example, an optical fiber is coated to prevent water ingression, which can lead to catastrophic failure due to water induced microcrack propagation. Typically, the fiber is coated with a polymer or polymers. In some cases the coating is applied in eight or more individual steps to protect the fiber from such failure. The most common protective coating is an ultra violet (UV) cured acrylate. Other coatings including fluoroacrylates, polyimides, Teflon fluoropolymers, and a number of other organic compounds.

Unfortunately, problems are associated with these protective coatings. The core of the fiber is often unpredictably located with respect to the outer circumference of the coating, hindering proper optical alignment for communication of light with the fiber.

Accordingly, the protective coating is often stripped away from a short length of the optical fiber prior to assembly of the length of fiber into a connector or optical package. The fiber is often mechanically stripped, which can damage the surface of the fiber and render the fiber more likely to fail in service. The fiber can also be stripped using hot sulfuric acid. However, the acid can degrade the fiber, including any remaining coatings, due to the wicking of the acid underneath one or more of the coatings. Stripping the fiber introduces a discontinuity in the protective coating where the coating suddenly ends and the stripped portion of the fiber begins. This discontinuity can concentrate stresses on the fiber at the discontinuity, also tending to promote failure of the fiber. The amount of stress concentrated can depend on the nature of the coating that is stripped.

It is also known to metallize, typically via electroplating, electroless plating, or vapor deposition, the cladding layer that is exposed upon stripping the fiber. The metallized cladding can be soldered into a ferrule, which ferrule is in turn soldered into a passage in an active or passive component package. "Glues," such as epoxy resins, and RTV silicone compounds are used to fill in gaps and to avoid microbend induced stresses that cause unacceptable optical performance degradation. To enhance the mechanical integrity of the optical assembly, a part of the fiber in the ferrule may retain the polymer layer, such that the core of the optical fiber may be displaced relative to and/or disposed at an angle to the longitudinal axis of the ferrule. Often the length of the passage is longer than the length of the ferrule, and because of the high variability in fiber thickness due to unpredictable thickness and/or location of the protective coating, as noted above, the passage includes a large diameter. This creates the larger gap to fill with the "glue" and also increases the risk of angular misalignment of the fiber.

After all of the foregoing--stripping, plating, and soldering a ferrule onto the fiber and into a package--it is typically still necessary for a technician to optically align the fiber and the device, that is, the receiver or transmitter in the package, with which the fiber communicates. Typically, the location of the packaged device or of a free end of the fiber is adjusted while measuring the transmission of light between the fiber and the device. When the location is found that corresponds to acceptable light transmission, the location of the device or the free end is fixed. In one common practice, a second ferrule is soldered to the fiber near the free end, and this ferrule is secured to the package by placing a clamp over the ferrule and welding the clamp to the package, thereby fixing the fiber in proper optical alignment with the device. This procedure is laborious and costly.

From the foregoing, it is apparent that improvement in methods and apparatus for communicating signals with an optical fiber would represent a welcome advance in the art. Accordingly, it is an object of the present invention to address one or more of the foregoing disadvantages or drawbacks of the prior art.

Other objects will become apparent below to one of ordinary skill in the art.

SUMMARY OF THE INVENTION

According to a preferred embodiment, an optical assembly for the communication of an optical signal between an optical fiber and a receiver or transmitter includes a body including a guideway and a first semiconductor optical element for conversion between electrical and optical signals and for receiving or transmitting light. The semiconductor optical element is mounted in register with the body. The optical assembly also includes an optical fiber having a first end, a core, a cladding surrounding the core, and a protective coating deposited on the cladding. The guideway receives a selected length of the optical fiber, where the selected length includes the entire length of the fiber received by the guideway. The selected length has not been stripped of a coating deposited on the cladding. When the selected length is received by the guideway, the first end of the optical fiber is optically aligned with the optical element such that neither the location of the first end nor the location of the optical element is adjusted responsive to the measurement of the transmission of light between the optical element and the optical fiber.

In another aspect of the invention, an optical apparatus includes a body including a guideway and a first semiconductor optical element for conversion between electrical and optical signals and for receiving or transmitting light. The semiconductor optical element is mounted in register with the body. The apparatus also includes an optical fiber, where the optical fiber extends from a first end to a second end and includes a core, a cladding surrounding the core, and a protective coating surrounding the cladding. The guideway receives a selected length of the optical fiber, and the protective coating is included on the fiber for at least a majority of the selected length. The selected length includes the entire length of the fiber received by the guideway. The optical fiber, when received by the guideway, has the first end optically aligned with the optical element such that neither the location of the first end nor the location of the optical element is adjusted responsive to the measurement of the transmission of light between the optical element and the optical fiber. The optical apparatus also includes a second guideway that receives a second selected length of the optical fiber, where the second selected length includes the entire length of the fiber received by the second guideway, and a second optical element that is optically aligned with the second end of the optical fiber. The protective coating is present along all of a length of the fiber, the length including the majority of the first selected length and a majority of the second selected lengths and the entire length of the optical fiber therebetween.

In yet a further aspect of the invention, an optical assembly for communication of an optical signal between an optical fiber and a receiver or transmitter includes a body including a guideway having a wall and a first semiconductor optical element for conversion between electrical and optical signals and for receiving or transmitting light. The semiconductor optical element is mounted in register with the body. The optical assembly also includes a length of optical fiber having a first end, a core, a cladding surrounding the core, and a coating deposited on the cladding. No other coating is deposited over the coating for the length of the fiber, and the coating has a thickness of less than about 1 micron. The length of optical fiber has an n-factor of at least 50. The guideway receives a selected length of the optical fiber such that the coating contacts the wall of the guideway, and the selected length includes the entire length of the fiber received by the guideway. The fiber includes the coating thereon for at least a majority of the selected length. The first end of the optical fiber is optically aligned with the optical element.

The invention also includes methods for communicating an optical signal between an optical fiber and a receiver or transmitter. In a preferred embodiment, the method includes providing a body; providing the body with a guideway; providing a semiconductor optical element for conversion between electrical and optical signals and for one of receiving and transmitting light; mounting the optical element in register with the body; providing an optical fiber having a first end, the optical fiber including a core, a cladding surrounding the core, and a hermetic coating deposited on the cladding; placing a selected length of the optical fiber in the guideway for being received thereby and for optically aligning the first end of the fiber with the optical element, the selected length being all of that portion of the optical fiber that is received by the guideway; refraining from stripping a coating in contact with the cladding from the selected length of the fiber; and wherein neither the location of the first end of the optical fiber nor the location of the optical element is adjusted responsive to the measurement of the transmission of light between the optical element and the optical fiber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an optical assembly according to the invention;

FIG. 2 is a cross section of the optical fiber of the optical assembly of FIG. 1 taken along section line 2--2;

FIG. 3A is cross section, taken along section line 3--3, of the guideway 16 of FIG. 1;

FIG. 3B is a cross section, similar to that of FIG. 3A, wherein the guideway 16 includes a cylindrically shaped wall;

FIG. 3C is a cross section showing the guideway including a fully cylindrical passage;

FIG. 3D is a perspective view of the guideway 16 of FIG. 3C;

FIG. 3E is a top view of the guideway of FIG. 1;

FIG. 4 is a flow chart illustrating method steps for communicating an optical signal between an optical fiber and a receiver or transmitter according to one practice of the invention;

FIG. 5A is a schematic illustration of an optical tap;

FIG. 5B depicts a plurality of optical assemblies of FIG. 1 interconnected by a combination of optical taps; and

FIG. 6 is a flow chart illustrating method steps for communicating an optical signal between an optical fiber and an optical element such as a receiver or transmitter, where the method includes the use of an optical tap.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of an optical assembly 10 for communication of an optical signal between an optical fiber and an optical element, which optical element can include a receiver or transmitter. Communication between, or communication with, as used herein, refers to the transmission of signals from one entity to another, the reception of signals by one entity from another, or both the reception and transmission of signals.

The optical assembly 10 includes a body 14 having a guideway 16. The body 14 and the guideway 16 can be unitary, in that one piece of material can be machined or otherwise shaped or formed to define the body 14 having the guideway 16, or can include a plurality of pieces, which pieces can be of different types of materials, that are integrated together to provide the body 14 having the guideway 16. The body 14 can include, but is not limited to, materials such as ceramics, plastics, including glass-impregnated plastics, and metals, such as machined or injection molded metals.

The optical assembly 10 can include an optical element 18 for conversion between electrical and optical signals and receiving and/or transmitting light, and an optical fiber 22. The optical element 18 can include a semiconductor substrate 23, such gallium arsenide or indium phosphide.

With reference to FIG. 2, which is a cross section of the optical fiber 22 taken along section line 2--2, the optical fiber 22 can include a core 24, a cladding 28 surrounding the core, and a protective coating or layer 30, which is preferably highly hermetic, surrounding the cladding 28. The optical fiber 22 can be adapted for the multimode propagation of light by the core 24, or alternatively, for single mode propagation of light by the core 24.

Referring again to FIG. 1, the guideway 16 receives a selected length 34 of the optical fiber, and the coating 30 is present along a majority of the selected length 34. Preferably, the coating 30 is present along all or nearly all of the selected length 34. When the selected length 34 of the optical fiber 22 is received by the guideway 16, the optical fiber 22 is sufficiently optically aligned. Neither the location of the end 38 of the optical fiber 22 nearer to the optical element 18 nor the location of the optical element 18 is adjusted responsive to the measurement of the transmission of light between the optical element 18 and the optical fiber 22.

The guideway 16 shown in FIG. 1 includes a V-groove. Such a V-groove can be micromachined into a silicon substrate 41, which is included by the body 14. For example, the dotted line 43 can represent the boundary between the silicon substrate 41 and the remainder of body 14, to which the silicon substrate 41 is appropriately mechanically secured or coupled. Micromachining refers to the use of photolithographic techniques to shape or otherwise define materials and structures, and often takes advantage of the preferential etching of certain materials, such as silicon.

A compliant material 50 can be provided for ensuring that the selected length 34 of optical fiber 22 stays in the guideway 16. The compliant material 50 can be secured to a cover 53 included with the body 14. Alternatively, the compliant material 50 can simply be disposed in or along the guideway 16.

The optical element 18 can be mounted in register with the body 14. Register, as used herein, refers to locating the optical element 18, or other element, relative to the body 14 such that a selected feature of the optical element 18 is within a selected distance of or otherwise arranged in a desired physical relationship to a selected feature associated with the body 14. The selected feature associated with the body can include the guideway 16, or another feature having a known relationship to the guideway or that will have a known relationship to the guideway 16 when the body 14 is provided with the guideway 16. Mounting the optical element 18 in register with the body 14 can include mounting the optical element 18 to the body 14 without close attention to the location of the optical element 18, and then providing the body 14 with the guideway 16, where the guideway 16 is located so as to be in desired relationship to the optical element 18.

The optical fiber 22, including the protective coating 30, preferably has an n-factor of 50 or higher; more preferably, the optical fiber 22 has an n-factor of 100 or higher, and most preferably, the optical fiber has an n-factor of 200 or higher. One protective, hermetic coating considered to be useful for the purposes of the present invention includes silicon carbide and is disclosed in U.S. Pat. No. 4,512,629, issued on Apr. 23, 1985 to Hanson et al. and assigned at the time of issuance to Hewlett-Packard Co., and herein incorporated by reference. Typical prior art fibers having a polymer coating have n values substantially less than 50, such as n values of 10-20.

Coatings in accordance with the invention are preferably 1) highly hermetic, 2) less than about a micron thick, and 3) do not include a polymer, though all of the foregoing need not all be included in the same fiber. The protective coating 30 can be primarily carbon, with, for example, silicon carbide formed at the interface between the coating 30 and the cladding 28.

Reception by the guideway 16 of the selected length 34, preferably with the outer circumference 42 immediately adjacent to a wall of the guideway 16, suitably locates core 24 of the optical fiber for the transmission or reception of optical signals. Preferably, the location of the core 24 relative to the outer circumference 42 of the coating does not vary by more than about 3 microns along the length of the fiber; more preferably the location of the core 24 relative to the outer circumference 42 of the coating 30 does not vary by more than about 2 microns along the length of the optical fiber 22, and most preferably, the location of the core 24 relative to the outer circumference 42 does not vary by more about 1 micron along the length of the fiber 22. For example, with reference to FIG. 2, the first radius R.sub.1 and the second radius R.sub.2 can be subtracted to determine the variation in the location of the core along the length of the optical fiber 22. If the coating is not uniformly deposited about the fiber, such that the core is offset, the radii R.sub.1 and R.sub.2 can correspond to the maximum radius at the point along the fiber at which the radius is measured.

It is considered that suitable hermetic coatings can be formed by carbides, nitrides and borides of elements such as, for example, aluminum, titanium and silicon, and can be formed by other similar materials as well. The thickness t of the protective coating 30 can be important in enhancing the properties of hermeticity and mechanical strength of the optical fiber 22. For example, for certain protective coatings of silicon carbide, one monolayer is not suitably hermetic and more than two monolayers is not considered to provide adequate mechanical strength, as it is prone to cracking. Thus, two monolayers of silicon carbide is the desired thickness. Accordingly, in one practice of the invention, the hermetic coating 30 has a thickness of a selected number of monolayers of a selected composition or compositions of material, and that the number of monolayers is selected so as to be high enough to provide hermeticity and low enough so as to avoid undue degradation of the mechanical strength of the optical fiber 22, such as by the optical fiber 22 being more prone to cracking. Typically, a suitable thickness in monolayers is less than 100 monolayers of a selected composition or compositions, and in one practice is from two to 20 monolayers. The suitable thickness can also be from two to ten monolayers of a selected composition or compositions.

Preferably, the protective coating 30 is deposited directly on the outermost cladding layer of the optical fiber 22 and the optical fiber 22 includes no other coatings deposited over the protective coating 30 such that the outer circumference 42 of the coating 30 is in contact with a wall of the guideway 16. The optical fiber 22 can be intubated, such as with a loose tube material such as hytrel. Preferably, the optical fiber 22 does not include a polymer layer deposited on a cladding layer thereof. It is possible that the coating 30 can be metallized, and the metallization soldered or epoxied to the guideway.

Hermetic coatings of the type preferred herein can often tolerate wide temperature excursions, such as to several hundreds of degrees Celsius above and below the temperature that conventional polymer coatings can withstand. Conventional polymer coated fibers, including the high temperature polyimide coatings, can suffer irreversible degradation at temperatures as low as 100 degrees Celsius, and the maximum temperature that typically can be tolerated is about 300 degrees Celsius. Polymer coated fiber can also become brittle at only a few tens of degrees below zero Celsius. Accordingly, in one practice, the invention can be used in applications that involve high temperature electronics, aerospace environments, earth science environments, and combustion engines.

Furthermore, the optical fiber 22 can be cleaved in the field and the optical assembly 10 put together from spooled fiber. A premade length of optical fiber terminated with appropriate plugs, such as injection-molded plugs, need not be ordered in advance. In one practice of the invention, a piece of fiber extending from the end 40 to the end 38 in FIG. 1 is simply cleaved to the proper length. The end 40 typically terminates at another device, which can include an optical assembly similar to optical assembly 10, as indicated schematically by reference numeral 10'.

In one practice of the invention, the integrated circuit 200 can include the optical element 18. However, the typical integrated circuit 200 includes a silicon semiconductor substrate and many materials suitable for the fabrication of the optical element 18 include gallium arsenide or indium phosphide or similar compounds that can be difficult to include with a silicon substrate so as to provide a high performance optical element 18. Accordingly, the yield may be lower in producing such an embodiment of the invention.

The optical fiber 22