Abstract: A package for at least one laser diode includes: leads configured to be electrically connected to the at least one laser diode; a base including a mounting surface on which the at least one laser diode is to be mounted and a lateral wall located around the mounting surface so as to surround the at least one laser diode, the lateral wall defining first through-holes and including a light-transmissive part configured to transmit a laser beam emitted from the at least one laser diode; and a lead holding member bonded to the lateral wall of the base and defining second through-holes. The leads are disposed through the first through-holes and the second through-holes. At least a central portion of each of the leads is made of copper.

Abstract: A stem for a semiconductor package, includes an eyelet having a first surface, a second surface opposite to the first surface, and a through-hole penetrating the eyelet from the first surface to the second surface, a metal base bonded to the second surface of the eyelet so as to cover one end of the through-hole, and a metal block having one end thereof inserted into the through-hole and bonded to the metal base inside the through-hole, and another end projecting from the first surface of the eyelet and including a device mounting surface on which a semiconductor device is mounted. The metal base has a thermal conductivity higher than or equal to a thermal conductivity of the eyelet, and a surface at the one end of the metal block matches the second surface of the eyelet.

Abstract: A package for at least one laser diode includes: leads configured to be electrically connected to the at least one laser diode; a base including a mounting surface on which the at least one laser diode is to be mounted and a lateral wall located around the mounting surface so as to surround the at least one laser diode, the lateral wall defining first through-holes and including a light-transmissive part configured to transmit a laser beam emitted from the at least one laser diode; and a lead holding member bonded to the lateral wall of the base and defining second through-holes. The leads are disposed through the first through-holes and the second through-holes. At least a central portion of each of the leads is made of copper.

Abstract: A stem for a semiconductor package, includes an eyelet having a first surface, a second surface opposite to the first surface, and a through-hole penetrating the eyelet from the first surface to the second surface, a metal base bonded to the second surface of the eyelet so as to cover one end of the through-hole, and a metal block having one end thereof inserted into the through-hole and bonded to the metal base inside the through-hole, and another end projecting from the first surface of the eyelet and including a device mounting surface on which a semiconductor device is mounted. The metal base has a thermal conductivity higher than or equal to a thermal conductivity of the eyelet, and a surface at the one end of the metal block matches the second surface of the eyelet.