The loss coupled DFB laser with the surface grating is presented. The type of laser is broad area laser, 87㎛ width, 600㎛ long. All the material parameters and device structures are calculated by C-coded program in this work. Also the optical interferometer and $CH_4/H_2$ RIE for InP etching are set up. The device characteristics, like a spectrum and L-I, are measured using a monochromater, a L-I measurement set-up, and an optical spectrum analyzer. The laser devices are lasing at 1.573㎛, 1.574㎛, 1.58㎛, 1.59㎛, and 1.6㎛. This randomly lasing characteristic is examined by the transfer matrix simulation. From this simulation, I affirm that the characteristic comes from the randomness of grating period, and estimate the quality of the grating as $σ_Λ$ is equal to 0.01.
