The present invention relates to a multi-wavelength laser diode, in which
an oscillating structure includes a semiconductor substrate, and a lower
cladding layer, an active layer and a ridge formed in their order on the
semiconductor substrate. A first metal layer is formed on a first face of
the oscillating structure including one end of the ridge, and made of a
metal having a high reflectivity in a first wavelength range of at least
a predetermined wavelength. A second metal layer is formed on the first
metal layer, the second metal layer being made of a metal having a high
reflectivity in a second wavelength range under the predetermined
wavelength. The multi-wavelength laser diode can improve-the reflective
layer structure to achieve a high reflectivity in the entire visible
light range.