Abstract: A light receiving holder includes an abutting portion and a welded portion and the welded portion includes a ring-shaped projection which extends from the welded portion and whose cross-section is smaller as it is closer to the tip of the projection. A cap of a casing constituting a light receiving unit is received in a through-hole of the light receiving holder. The projection is brought into contact with a flange of the casing. Current is supplied between a lower electrode and an upper electrode to resistance-weld the projection to the flange. At this time, an angle is provided between a facing face of the lower electrode and a facing face of the upper electrode so that the light receiving holder is welded to the light receiving unit while an angle of the light receiving unit relative to the light receiving holder is adjusted.

Abstract: There is provided a small-diameter LD module which facilitates welding of a ferrule holder and a lens holder. An LD and a lens barrel having a lens press-fitted therein are supported by a lens holder, and a ferrule is supported by a ferrule holder. The diameter of the ferrule holder is set smaller than that of the lens holder. After the optical axes of the lens (and the LD) and an optical fiber are aligned, the lens holder and the ferrule holder are connected at welds, and then, the lens holder and a protective casing are connected at welds.