Semiconductor laser excitation solid-state laser

A semiconductor laser excitation solid-state laser, comprising:

• a planar waveguide-type solid-state laser element in which claddings with a refraction index different from that of a plate-shaped solid-state laser medium are formed on both surfaces of the solid-state laser medium, and which is disposed on a solid-state laser substrate;
• an LD array in which a light-emitting layer sandwiched between cladding layers is formed on an LD substrate, and which generates laser light for exciting the solid-state laser medium from an end face thereof;
• and
• a sub-mount substrate on which joining layers of two different thicknesses are formed on the same plane;
• wherein
• the planar waveguide-type solid-state laser element is joined to the sub-mount substrate on a surface on the opposite side of a surface on which the solid-state laser substrate is mounted, via a joining layer of one of the thicknesses out of the joining layers of the two different thicknesses, and the LD array is joined to the sub-mount substrate on a surface on the light-emitting layer side, via another joining layer of the other thickness out of the joining layers of the two different thicknesses.