Patent Application
20070155197
The present invention relates to semiconductor laser packages used in mounting lasers on optoelectronic circuit boards. More specifically, the present invention relates to adaptors suitable for use in optoelectronic circuit boards for adapting the pin-out of a first laser package to a desired pin-out on a printed circuit board.
Semiconductor laser devices are used for many purposes in various applications today. These devices such as edge-emitting lasers and vertical cavity surface emitting lasers (VCSELs) find application in the optoelectronics and the telecommunications industry. Deployment of lasers in optoelectronic circuit boards is often done using a hermetically sealed housing or a package to house the laser and possibly various other optical or electronic devices. This semiconductor laser package protects the electronic and optical devices from degradation by deleterious ambient contaminants, such as moisture and dust in the atmosphere. Further, the semiconductor laser package serves as a heat dissipater to cool the sealed components in it.
Many semiconductor laser package designs for VCSELs and edge-emitting lasers are known in the art. Two such semiconductor laser package designs used for optoelectronic circuit boards are the coaxial laser package (or “Transistor outline” TO can) and the rectangular, flat “butterfly” laser package.
The butterfly laser package design is widely accepted in the optoelectronic industry.
Further, the coaxial laser package design has shown great adoption potential due to its ease of manufacturing and low cost.
Fiber module 204 is used to couple the laser lights coming out of TO header subassembly 202 for its subsequent usage in optoelectronic device. A laser diode, other optical devices and IC components (not shown in figure) are mounted inside TO header subassembly 202 and hermetically sealed with a TO-can 208.
It is desirable to use a coaxial laser package in optoelectronic circuit boards due to their ease of manufacturing and low cost. However, existing optoelectronic circuit board designs are adapted to use a butterfly laser package. The differences between butterfly pin-out 106 and coaxial pin-out 206 make it impossible to directly replace a butterfly laser package with a coaxial laser package on existing optoelectronic circuit board designs. Thus, there is a need for an invention to facilitate the use of a coaxial laser package in place of a butterfly laser package.
The present invention discloses an adaptor suitable for use in an optoelectronic circuit board, for adapting a package pin-out arrangement to a desired pin-out arrangement on a printed circuit board.
In an embodiment, the present invention discloses an adaptor suitable for use in an optoelectronic circuit boards for adapting a package pin-out arrangement to a desired pin-out arrangement on a printed circuit board. The adaptor comprises a pin-in arrangement designed to electrically couple with the package pin-out arrangement, an adaptor pin-out arrangement that is geometrically identical to the desired pin-out, and a flex-circuit that provides a plurality of electrical paths to connect the pin-in arrangement with the adaptor pin-out arrangement.
In another embodiment, the present invention discloses an adaptor suitable for use in an optoelectronic circuit boards for adapting a package pin-out arrangement to a desired package pin-out arrangement on a printed circuit board. The adaptor comprises a flex-circuit. The flex-circuit further comprises a pin-in arrangement designed to electrically couple with the package pin-out arrangement, a pin-out that is geometrically identical to the desired pin-out, and one-to-one electrical connections between the pin-out of the package pin-out arrangement and the adaptor pin-out arrangement.
Various embodiments of the present invention are suitable for adapting the pin-out of a coaxial laser package to the pin-out of a butterfly laser package.
The present invention will hereinafter be described in conjunction with the appended drawings provided to illustrate the invention, wherein like designations denote like elements, and in which:
In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art will appreciate that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims.
The present invention discloses an adaptor for adapting the pin-out of a first laser package to a desired pin-out arrangement on a printed circuit board. In prior art, semiconductor laser packages of one design can only be used with optoelectronic circuit boards of a corresponding design. This is because the pin-out of the first laser package may not correspond with the desired pin-out for use with the optoelectronic circuit board. The adaptor according to the present invention provides the flexibility to adapt the pin-out of a first laser package for use in conjunction with an optoelectronic circuit board that requires a different pin-out (hereinafter desired pin-out).
The adaptor, in accordance with various embodiments of the present invention, comprises a pin-in arrangement that mates with the pin-out of the first laser package. Further, the adaptor comprises an adaptor pin-out arrangement that is geometrically identical to the desired pin-out arrangement. The pin-in arrangement and the adaptor pin-out arrangement are electrically connected via a plurality of electrical paths. The adaptor pin-out arrangement may further be connected to the optoelectronic circuit board. This provides an inexpensive and convenient way to adapt the pin-out of the first laser package for use with any desired optoelectronic circuit boards.
In an embodiment, the present invention may be employed to adapt the pin-out of a coaxial laser package to a butterfly laser package.
In an embodiment of the present invention, flex-circuit 400 is made of copper foils, polyimide and adhesive laminates. It will be apparent to the reader that various suitable materials known in the art may be used for construction of flex-circuit 400.
Desired pin-out 402 geometrically simulates butterfly pin-out 106 (as shown in
In an embodiment of the present invention, flex-circuit 400 can be bended to take a desired shape using appropriate forming tools. It will be apparent to one skilled in the art that various orientations or shapes of flex-circuit 400 can be attained using suitable forming tool known in the art.
Flex-circuit 400 further comprises electronic traces (not shown in figure) running inside flex-circuit 400 to connect the pins of coaxial pin-out 206 to the corresponding pins of desired pin-out 402 formed on flex-circuit 400. These features eliminate the need to bend coaxial pin-out 206 formed on coaxial laser package 200 to make it adaptable for butterfly application.
In an embodiment of the present invention, clamshell 600 has a cylindrical bore 606, which is formed by joining semi-circular half formed within top portion 602 with another semi-circular half formed within bottom portion 604. In various embodiments, there may be other internal cavities (not shown in the Figure) formed within clamshell 600 to accommodate the first laser package and flex-circuit 400 suitably.
Clamshell 600 serves to hold flex-circuit 400 and coaxial laser package 200 together in a single flat format. Further, it serves as a heat sink to dissipate heat generated from laser diode and other internal heat sources. For example, clamshell 600 is thermally conductive to the hot side of Thermal Electronic Cooler (TEC) in a cooled first laser package, and serves to dissipate the heat produced by the laser diodes and TEC in the first laser package.
In an embodiment of the present invention, top portion 602 and bottom portion 604 are fastened together using screws. In another embodiment of the present invention, top portion 602 and bottom portion 604 are held together by epoxy bonding. It will be apparent to one skilled in the art that various fastening means can be used to join top portion 602 and bottom portion 604 of clamshell 600, depending on the application.
In another embodiment of the present invention clamshell 600 can be made by machining or by molding using materials with high thermal conductivity, such as aluminum, copper or other metals. It will be apparent to the one skilled in the art that various other known material can be used for the construction of clamshell 600 without deviating from the scope of the present invention.
In yet another embodiment of the present invention, an interface material can be interposed between TO-can 208 of coaxial laser package 200 and cylindrical bore 606 of clamshell 600 for thermal contact purposes. It will be apparent to the one skilled in the art that various known materials can be used as for such thermal contact including for non-limiting example thermal epoxy, and thermal pads.
In an embodiment of the present invention, the footprint of clamshell 600 is the same as the footprint of butterfly laser package 100. In another embodiment of the present invention, the footprint of clamshell 600 is selected depending upon the application that uses the adaptor.
In an embodiment of the present invention, the electrical traces within flex-circuit 400 may provide one-to-one connections between the pins of coaxial pin-out 206 and desired pin-out 402. In another embodiment, certain pins of coaxial pin-out 206 may be connected to more than one pins of desired pin-out 402. Alternatively, certain pins in coaxial pin-out 206 may be not connected to pins of desired pin-out 402. It would be apparent to one skilled in the art that various connections between the pins of coaxial pin-out 206 and the pins of desired pin-out 402 may be used based on the application of the adaptor, without deviating from the spirit and scope of the present invention.
In an embodiment of the present invention, the screwing together of top portion 602 and bottom portion 604 serves to seal adapted laser package 700. In another embodiment, epoxy bonding is used to seal adapted laser package 700. It will be apparent to one skilled in the art that various other means of sealing the first laser package can be employed without deviating from the scope of the invention.
It will be apparent to one skilled in the art that a large variety designs and materials that are known in the art may be used for flex-circuit 400 and clamshell 600 to function as adaptor providing a plurality of electrical paths to connect the pin-in arrangement with the adaptor pin-out arrangement.
The examples under the present invention, detailed in the illustrative examples contained here, are described using terms and constructs drawn largely from an adaptor to adapt a coaxial laser package for butterfly applications. But use of these examples should not be interpreted to limiting the invention to these semiconductor laser packages. The methods and principles disclosed by the present invention can be of use and provided to adapt any semiconductor laser package for any application.
While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art without departing from the spirit and scope of the invention as described in the claims.
