Patent ID: 7507035

Claim:
An optical module with a co-axial package having a metal cap and a metal stem fixed by the resistance-welding to each other, characterized in that, the metal stem includes a first portion with a first diameter, a second portion with a second diameter greater than the first diameter, and a step between the first portion and the second portion, the first portion mounting a semiconductor optical device and having a deformed portion caused by the resistance-welding, the metal cap includes a first portion with a third diameter, a second portion with a fourth diameter greater than the third diameter, and a step between the first portion of the metal cap and the second portion of the metal cap, the first portion of the metal cap having a deformed portion caused by the resistance-welding, the first diameter of the metal stem is smaller than the fourth diameter of the metal cap, and the third diameter of the metal cap is smaller than the second diameter of the metal stem, and the second diameter of the metal stem and the fourth diameter of the metal cap are smaller than or equal to a diameter of an outermost surface of the optical module.