Optical module and manufacturing method of optical module

An optical module comprising:

• an optical semiconductor element;
• a stem including a signal pin extending in a first direction and a ground pin, the signal pin being electrically connected to the optical semiconductor element for transmitting an electrical signal, the ground pin being configured to provide a reference potential of the electrical signal, the ground pin having a base and a flat head provided at a tip of the base, the flat head having a top surface crossing the first direction;
• and
• a circuit board extending in a second direction crossing the first direction, the circuit board including a signal through-hole, a ground through-hole, a signal line extending in the second direction, and a ground layer, the signal through-hole being configured to be pierced by the signal pin, the ground through-hole being configured to be pierced by the ground pin, the signal line being configured to be electrically connected with the signal pin, the ground layer being configured to be electrically connected with the ground pin,
• wherein the ground through-hole includes a first ground through-hole and a second ground through-hole, the signal line being sandwiched between the first ground through-hole and the second ground through-hole in a third direction crossing the first direction and the second direction, and
• the ground pin includes a first ground pin and a second ground pin, the first ground pin piercing the first ground through-hole and the second ground pin piercing the second ground through-hole.

An optical module comprising:

• an optical semiconductor element;
• a stem including a signal pin extending in a first direction and a ground pin, the signal pin being electrically connected to the optical semiconductor element for transmitting an electrical signal, the ground pin being configured to provide a reference potential of the electrical signal, the ground pin having a base extending from the stem in the first direction and a flat head provided at a tip of the base, the flat head having a top surface crossing the first direction;
• and
• a circuit board extending in a second direction crossing the first direction, the circuit board including a signal through-hole, a ground through-hole, a signal line extending in the second direction, and a ground layer, the signal through-hole being configured to be pierced by the signal pin, the ground through-hole being configured to be pierced by the ground pin, the signal line being configured to be electrically connected with the signal pin, the ground layer being configured to be electrically connected with the ground pin,
• wherein the circuit board is sandwiched between the flat head and an outer surface of the stem in the first direction.