Fiber-optic communication systems are commonly used for transmitting/receiving data. Because as of yet there are no practical optical computers, the data typically originates as an electrical signal that a transmitter converts into an optical (light) signal for transmission over an optical fiber. A receiver then converts the optical signal back into an electronic signal for processing of the data. More specifically, an optoelectronic light source such as a light emitter diode (LED) converts the electrical signal in the optical signal, and an optoelectronic light detector such as a photo diode converts the optical signal back into an electrical signal.
FIG. 1 is an exploded view of a conventional optoelectronic module 10 for transmitting optical signals to and receiving optical signals from a fiber-optic cable 12 that includes one or more optical fibers 14 (only one shown). The module 10 includes an optoelectronic transmit/receive assembly 16 and a fiber-optic interface 18 for releasably coupling the fiber-optic cable 12 to the assembly 16. The interface 18 includes a receptacle 20 that is typically made of plastic and that is mounted to the optoelectronic assembly 16. The receptacle 20 includes latches 22 that mate with a connector 24 for releasably connecting the cable 12 to the receptacle 20. The interface 18 also includes an alignment device 25 and lens 26 for respectively aligning a photo diode/LED 30 with the fiber 14 and for focusing the optical beam formed by the signal.
To assemble the module 10, first the lens 26 is mounted to the alignment device 25, and then the alignment device 25 is mounted to the optoelectronic assembly 16 by inserting the guide pins 28 (only one shown) into corresponding holes (not shown) in the panel 32 of the assembly 16. Next, the lens 26 is optically aligned with the component 30. Once the lens and component 30 are aligned, the alignment device 25 is fixed to the panel 32 with adhesive. Next, the receptacle 20 is mounted over and aligned with the alignment device 25 and fixed in place with adhesive. Because the optical alignment of the fiber 14 with the component 30 must be relatively precise—within microns—a fixture (not shown) is used to keep the alignment device 25 and the receptacle 20 in alignment while the adhesive cures.
Although, the module 10 is useful in many applications it may be unsuitable for certain situations as described below.
Unfortunately, because the receptacle 20 is typically made from plastic, mounting the module 10 to a system printed-circuit board (not shown) or using the module 10 for an extended period of time may damage the fiber-optic interface 18. To mount the module 10 to a board, the module 10 is typically soldered to the board. Soldering generates heat that can raise the temperature of the interface 18 in excess of 230° C. If the temperature of the receptacle 20 is high enough, the plastic can release gas or deform the connector latches 22 that releasably retain the cable 12 to the interface 18. Gas released by the plastic can fog the lens 26, which may distort or prevent an optical signal from passing between the fiber 14 and the component 30. Deformed connector latches 22 may cause the fiber 14 to misalign with the lens 26 when attached to the receptacle 20, or may altogether prevent connection of the cable 12 to the interface 18.
In addition, it is sometimes desired that the receptacle 20 suppress electromagnetic interference (EMI) generated by the circuitry (not shown) of the assembly 16. But because plastic typically cannot suppress EMI, the receptacle 20 must be appropriately modified. Typical modifications include either plating the receptacle 20 with a metal or mixing metal into the plastic material used to make the receptacle 20. These modifications, however, are typically expensive, and thus typically increase the cost of the interface 18.
Moreover, the process of mounting the receptacle 20 to the assembly 16 is not simple. Because this process entails gluing the receptacle 20 and alignment device 25 to the panel 32 using an alignment fixture (not shown), the time required to assemble the module 10 includes the time the adhesive takes to cure and the time one takes to assemble the module 10 in the fixture and remove the module 10 from the fixture. Thus, the time spent assembling and removing the module 10 from the fixture may also increase the cost of the module 10.
The module is further discussed in U.S. patent application Ser. No. 10/174,002 titled ACTIVELY ALIGNED OPTOELECTRONIC DEVICE and filed 17 Jun. 2002, which is incorporated by reference.
In view of the foregoing, there is a need for a fiber-optic receptacle that can withstand high temperatures, withstand use over an extended period of time, suppress EMI, and be easily mounted.