Method for manufacturing optical device and optical device

An optical device having a laser diode, wherein the laser diode comprises:

• a substrate;
• a n-type clad layer formed on the substrate and including a nitride semiconductor layer having n-type conductivity;
• a light-emitting layer formed on the n-type clad layer and including at least one quantum well;
• a p-type clad layer formed on the light-emitting layer and including a nitride semiconductor layer having p-type conductivity, and
• a photodetector formed on the substrate, having a mesa structure and capable of receiving and detecting light emitted from the laser diode,
• wherein at least a portion of the n-type clad layer, the light-emitting layer and the p-type clad layer constitute a mesa structure having a resonator end face, and entire side surfaces of the mesa structure are covered with a light reflecting layer,
• wherein all side surfaces of the mesa structure of the photodetector are covered with the light reflecting layer, and
• where a light reflectance of the light reflecting layer is 50% or more with respect to a desired wavelength.