Semiconductor laser device

A semiconductor laser device comprising:

• a support base having a plurality of mounting surfaces arranged in a first direction, wherein heights of the mounting surfaces from a reference plane that is parallel to the first direction decrease stepwise or gradually along the first direction;
• a first semiconductor laser element directly or indirectly secured to a first mounting surface among the plurality of mounting surfaces, the first semiconductor laser element being configured to emit first laser light in a second direction that intersects the first direction in a plan view from a direction normal to the reference plane;
• a second semiconductor laser element directly or indirectly secured to a second mounting surface among the plurality of mounting surfaces, the second semiconductor laser element being configured to emit second laser light in the second direction in the plan view;
• a first slow-axis collimator lens directly or indirectly secured to the first mounting surface, the first slow-axis collimator lens being located at a position at which the first laser light is incident;
• a second slow-axis collimator lens directly or indirectly secured to the second mounting surface, the second slow-axis collimator lens being located at a position at which the second laser light is incident;
• and
• a first sealing cover having a lateral wall surrounding the first semiconductor laser element and the second semiconductor laser element, wherein a lower end of the lateral wall is bonded to the support base, wherein the first sealing cover defines an inner space in which the first semiconductor laser element and the second semiconductor laser element are held, and wherein the first sealing cover has a light-transmitting region configured to transmit the first laser light and the second laser light, wherein:
• each of the plurality of mounting surfaces includes a first region covered with the first sealing cover and a second region located outside the first sealing cover;
• the support base has a first groove receiving at least part of the lateral wall of the first sealing cover,
• a part or an entirety of the lower end of the lateral wall of the first sealing cover is bonded to a bottom surface of the first groove, and
• a part of the first groove is located in the plurality of mounting surfaces at a position between the first and second semiconductor laser elements and the first and second slow-axis collimator lenses.