a stem from which a pedestal portion integrally protrudes;

a photoelectric device configured to convert an optical signal and an electrical signal from at least one to another;

a mounting substrate on which the photoelectric device is mounted;

a support block with a ceramic body, the support block having a metallization pattern on a surface of the ceramic body, the mounting substrate overlapping with the metallization pattern and being mounted on the support block; and

a first wire electrically connecting the pedestal portion and the metallization pattern,

wherein the surface of the ceramic body includes a pair of first surfaces facing in opposite directions along a first direction, the surface of the ceramic body including a pair of second surfaces facing in opposite directions along a second direction intersecting with the first direction, the surface of the ceramic body including a pair of third surfaces facing in opposite directions along a third direction intersecting with both the first direction and the second direction,

wherein the metallization pattern includes a pair of first metal films on the respective pair of first surfaces, the metallization pattern including a second metal film on at least one of the pair of second surfaces to connect the pair of first metal films,

wherein the support block includes at least one connection conductor connecting the pair of first metal films, the at least one connection conductor being at least one of a castellation conductor and a via conductor, the castellation conductor being on at least one of the pair of third surfaces of the ceramic body, and the via conductor being through the ceramic body between the pair of first surfaces,

wherein the pair of third surfaces includes a region not covered with the metallization pattern,

wherein the mounting substrate is mounted on one of the pair of first surfaces, and

wherein one end of the first wire is bonded to a corresponding one of the pair of first metal films or the at least one connection conductor, at a position adjacent to or overlapping with the at least one connection conductor, on another of the pair of first surfaces.