Patent ID: 7773648

Claim:
A laser diode comprising: a substrate; a multi-layer film including a first conductivity type cladding layer provided on the substrate, a first conductivity type guide layer provided on the first conductivity type cladding layer, an active layer provided on the first conductivity type guide layer, a second conductivity type guide layer provided on the active layer, and a second conductivity type cladding layer provided on the second conductivity type guide layer, each of the layers being made of a nitride-based III-V group compound semiconductor; a first protective layer provided on a light emitting surface of the active layer configured to protect the light emitting surface, and is made of nitride including aluminum; and a second protective layer provided on the first protective layer configured to prevent the first protective layer from being oxidized, and is made of nitride including silicon, the second protective layer having a refractive index different from that of the first protective layer, wherein each of the first and second protective layers has a thickness of 0.25 nm or more but 50 nm or less.