Patent ID: 8053803

Claim:
A package for an optical semiconductor element, the package comprising: a stem body having a first sealing hole and a second sealing hole therein; a first lead pin adapted to be a power lead pin and having a first glass sealing portion which is sealed with a first sealing glass in the first sealing hole; and a second lead pin adapted to be a signal lead pin and having a second glass sealing portion which is sealed with a second sealing glass in the second sealing hole, wherein characteristic impedance of the second glass sealing portion is adjusted to a given value, wherein the characteristic impedance Zo is given by: Zo =(138/ Er 1/2 )×log( D/d ), where a hole diameter of the second sealing hole is D, a wire diameter of the second lead pin is d, and a dielectric constant of the second sealing glass is Er, and wherein the second sealing glass includes bubbles, and the dielectric constant Er of the second sealing glass is set by controlling an amount of the bubbles contained in the second sealing glass, and wherein the dielectric constant of the second sealing glass is lower than a dielectric constant of the first sealing glass.