Submount, light emitting device, and optical module

A light emitting device comprising:

• a submount for being mounted with a light emitting device, the submount comprising:
• a base including a first surface extending in a first direction and in a second direction that is orthogonal to the first direction;
• a first electrode extending in the first direction and in the second direction on the first surface, the first electrode including:
• a first end in the second direction, and
• a second end in an opposite direction of the second direction, the second end extending in the first direction;
• and
• a second electrode extending in the first direction and in the second direction on the first surface, the second electrode including:
• a third end in the opposite direction of the second direction, the third end being separated from the first end in the second direction with a gap therebetween, and
• a fourth end in the second direction, the fourth end extending in the first direction, wherein the second electrode has a second width between the third end and the fourth end in the second direction and the second width differs according to a position in the first direction;
• and
• a light emitting element comprising:
• a rear surface placed on the first electrode and electrically connected to the first electrode,
• an outer surface positioned on an opposite side to the rear surface and which is electrically connected to the second electrode via a conductor, and
• a side edge extending in the first direction closer along the first end than the second end of the first electrode, wherein:
• at first position in the first direction, the side edge is located a first distance from the first end of the first electrode,
• at a second position in the first direction, the side edge is located a second distance from the first end of the first electrode,
• the first distance is less than the second distance,
• the second electrode is connected to a bonding wire via a solder at the first position,
• the second width of the second electrode is wider at the first position than at the second position in the first direction so as to ensure heat dissipation by increasing heat quantity transmitted from the light emitting element via the first electrode at the second position where a width of the first electrode is wide comparing to heat quantity transmitted from the light emitting element via the first electrode at the first position where a width of the first electrode is narrow, and
• the light emitting element is mounted on the first electrode as a position closer to the first end of the first electrode than the second end of the first electrode.