A surface-emission laser diode includes a distributed Bragg reflector tuned to
wavelength of 1.1 m or longer, wherein the distributed Bragg reflector includes
an alternate repetition of a low-refractive index layer and a high-refractive index
layer, with a heterospike buffer layer having an intermediate refractive index
interposed therebetween with a thickness in the range of 5-50 nm.