Patent ID: 7065117

Claim:
A semiconductor laser element comprising: a stack of a plurality of layers having cleaved faces which are perpendicular to a light propagation direction and function as resonator faces; and at least one protection layer formed on at least one of said cleaved faces; wherein each of said at least one protection layer includes at least first, second, and third sublayers, said first sublayer is formed nearest to said stack among said at least first, second, and third sublayers, and made of a material which does not contain oxygen as a constituent element, said second sublayer which is made of a material comprising an oxide produced by oxidizing a portion of said first sublayer, and has a thickness d 2 , said third sublayer is formed farthest from said stack among said at least first, second, and third sublayers, and made of a material comprising an oxide, said first and second sublayers have a total thickness d 1 , and said total thickness d 1 and said thickness d 2 of said second sublayer satisfy a relationship, 0.1≦d 2 /d 1 ≦0.9.