Patent Document

BACKGROUND 
     This invention relates generally to packages for optical modules and, particularly, to packages that receive an optical fiber and provide electrical connections thereto. 
     Standard techniques to carry an electrical signal across the wall of a package for optical modules include multi-layer ceramic inserts. Standard ceramic packages for optical modules, commonly called butterfly packages, may include a base, a fiber feed-through, a can body, and a ring frame made of metal, as well as one or more multi-layer ceramic inserts that receive electrical connectors. A lid is typically used to hermetically close the package by welding or soldering to the ring frame. 
     Commonly one or more opto-electronic components in the packages need to be cooled down or maintained at a given temperature. This is usually done using thermoelectric coolers based on the Peltier effect. 
     The power needed by the thermoelectric cooler to maintain the package at the preset temperature is usually much greater than the original thermal load to dissipate. It is therefore important to reduce or minimize the thermal load on the thermoelectric cooler if it is desirable to minimize or reduce the power dissipated by the opto-electronic package. 
     In some cases not all of the opto-electronic components in the package need to be cooled down. But, generally, for performance reasons, the cooled and uncooled components need to be located very close to one another. 
     Thus, there is a need for better ways to cool packages for optical modules. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an enlarged cross-sectional view of one embodiment of the present invention; and 
     FIG. 2 is an enlarged perspective view of another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIG. 1, in one embodiment of the present invention, the optical package  10  for an optical module includes a base  12 , a can body  18 , and a ring frame  16  made of metal, as well as one or more ceramic inserts  14  that receive electrical connectors. A lid (not shown) may be used to hermetically close the package  10  by welding or soldering to the ring frame  16 . Various electrical connections  20  may be made through the ceramic insert  14 . 
     A heat sink or heat dissipating structure  110  may be secured to the base  12 . A thermoelectric cooler  101  may be positioned within the package  10  on the base  12 . Components, such as the component  102 , that do not require temperature control may be mounted on a riser  100  which moves those components away from components that must be cooled and away from the thermoelectric cooler  101 . The components  104  that need to be at a controlled temperature and/or cooled are mounted directly on or over the thermoelectric cooler  101  in one embodiment. The cooled and uncooled surfaces can be in the same or different planes. 
     Electrical connections between the uncooled submount  102  and the cooled submount  107  can be provided by flexible electrical connections  106 . For example, the connection  106  may also be a wire bond, flexible circuit, or a single submount, as examples. An integrated circuit  102  may be mounted on the uncooled submount  103  and an integrated circuit  105  may be mounted on the cooled submount  107 . The components  102  and  105  may be electrically connected by suitable connections  106 . 
     Referring to FIG. 2, in accordance with another embodiment of the present invention, a thermoelectric cooler  401  that may be mounted in an opto-electronic package (not shown) includes the riser  402 , which corresponds to the riser  100  in FIG.  1 . The riser  402  is integrated into the thermoelectric cooler  401  through the hot side  403 . 
     The cooler  401  develops a cool top surface  404  and an uncooled top surface  405 . The two surfaces  404  and  405  can be on the same plane or on different planes (as shown) to accommodate stack up height differences on the cooled and uncooled load. 
     A wire bond  406  may be utilized to connect the circuits  410  and  408 . The thermoelectric cooler  401  may also include a wire bondable pad  406  for power connections, as well it could have electrical leads (not shown) for power connections. 
     Thus, in accordance with some embodiments of the present invention, heat from the uncooled side passes downwardly to the heat sink  110  on the right. Additional heat, generated by the components mounted on the cooled side, such as circuit  105  or  408 , and by the thermoelectric cooler  101  itself, passes downwardly to the left. While the heat load is dissipated using a finned heat sink  110  in the embodiment shown in FIG. 1, other mechanisms may also be utilized to evacuate the heat load. 
     In accordance with some embodiments of the present invention, the thermal load on the thermoelectric cooler  101  or  401  may be reduced or minimized. Similarly, the thermoelectric cooler current to transfer the thermal load may be reduced or minimized. In some embodiments, the heat dissipation at the module level may be reduced or minimized. In some embodiments, the optical module manufacturing may be reduced or minimized by adding the passive thermal path to the butterfly can or the thermoelectric cooler. In some embodiments, the level of integration of the optical electronic components may be increased because a laser diode driver or other high powered, high speed, components may be integrated into the opto-electronic package. In addition, the opto-electronic package may provide electromagnetic shielding of the laser diode driver or other electronic components in some embodiments. 
     While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.

Technology Category: 5