Planar waveguide laser apparatus

A planar waveguide laser apparatus comprising:

• a planar waveguide comprising a core formed from a laser medium for absorbing pump light and claddings bonded to an upper surface and a lower surface of the core, each cladding having a smaller refractive index than the laser medium;
• a pump light generation source for emitting the pump light to a side surface of the core;
• and
• laser light reflection films formed on, out of four side surfaces of the core, two opposite side surfaces that are different from the side surface to which the pump light is emitted by the pump light generation source, wherein
• a structure of at least one side surface of two opposite side surfaces, out of four side surfaces of the planar waveguide, that are different from the side surface to which the pump light is emitted by the pump light generation source, the at least one side surface including at least one cladding surface and a core surface, and the structure of the at least one side surface is a ridge structure in which a part of the at least one side surface is recessed.