Abstract: A multi-lane optical apparatus is disclosed. The optical apparatus includes monitor photodiodes (mPD) whose number corresponds to a number of lanes. The mPDs are arranged in an array so as to intersect optical axes of the respective lanes. The mPD has a light-sensitive area and an electrode that are arranged on a diagonal connecting two corners. The light-sensitive area is disposed offset from the center of the mPD. The mPDs in outermost are disposed such that the respective electrodes face inward.

Abstract: A multi-lane optical apparatus is disclosed. The optical apparatus includes monitor photodiodes (mPD) whose number corresponds to a number of lanes. The mPDs are arranged in an array so as to intersect optical axes of the respective lanes. The mPD has a light-sensitive area and an electrode that are arranged on a diagonal connecting two corners. The light-sensitive area is disposed offset from the center of the mPD. The mPDs in outermost are disposed such that the respective electrodes face inward.

Abstract: A high projection is provided outside the bottom surface of a cap and a low and small protrusion is provided inside the projection. The projection is resistance-welded to a stem by allowing the projection to abut the stem so as to supply an electric current thereto. Even if melt particles flow inwardly, they are blocked by the small protrusion arranged inside so as not to enter the internal space, thereby eliminating a tapping test of an optical device and an optical module.

Abstract: In a conventional resistance welding-use electrode, a foot portion at the end is divided into three segments. An object such as a cap is inserted into a hole at the end. The foot portion is bent inward to hold the object by a force, and the object (cap) is pressed to a stem. Under this condition, a current is fed to perform resistance welding. A gap remains between the individual segments of the foot portion. Therefore, the current density is uneven, producing unevenness in the welding. A soft object may deform. The electrode wears and deforms due to repeated use, reducing its useful life. Because of the existence of the gap, pressing marks are sometimes formed in the welded portion. In the present invention, a permanent magnet is embedded at the end portion of the electrode to hold the object by magnetic force of the permanent magnet.