A waveguide type photoreceptor device of the present invention comprises a waveguide
16a disposed on a Fe-doped InP substrate, the waveguide including
an n-cladding layer connected to an n-electrode, an n-light guide layer, a light
absorption layer, a p-light guide layer, and a p-cladding layer connected to a
p-electrode, laminated onto one another over the Fe-doped InP substrate, and the
ratio of the layer thickness of the thicker one of the n-light guide layer and
the p-light guide layer to that of the thinner one being between 1.3 and 5 both inclusive.