The 'TO' encapsulation actually refers TO the supply-hole Outline or the supply-hole encapsulation technology that the supply-chain Transistor provides. Is now more commonly used in the application of microelectronic devices packaging.

Compared with other encapsulation technologies, the advantages of TO encapsulation are small parasitic parameters, low cost, relatively simple process, and more flexible and convenient TO use. Therefore, this kind of encapsulator is often used TO encapsulate PD, LD, LED and optical receiver devices and components. Over the years, with the reduction of laser threshold for many similar TO meet with, such as short distance communication and the connection between the backplane, with out cooling TO encapsulate laser and its comprehensive application, on the packaging cost has a great advantage TO packaging, the extensive research and people TO the packaging technology TO encapsulate laser rate is as high as 50 gb/high speed TO form enclosed laser in recent years more and more get the favour of people. In the TO encapsulate semiconductor laser, transitional heat sink with high heat conductivity and heat sink combination structure, effectively enhance the TO encapsulate the cooling characteristics of semiconductor laser, especially with double heat sink structure, but also will work the heat generated by the laser chip by N and P while at the same time guide base TO more effectively enhance the TO encapsulate semiconductor laser cooling capacity, greatly TO reduce temperature, laser active OuDeJie minimize the thermal resistance of laser, so as TO prolong the service life of semiconductor laser.