Semiconductor laser

The semiconductor laser is sequentially provided with a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper limiting layer from bottom to top, the active layer comprises a plurality of quantum wells; the lower waveguide layer comprises a first lower waveguide layer and a second lower waveguide layer; wherein the Philip ionization degree of the first lower waveguide layer is smaller than the Philip ionization degree of the second lower waveguide layer. According to the invention, the semiconductor laser is formed through the connection, and the Philips ionization degree of the first lower waveguide layer is smaller than the Philips ionization degree of the second lower waveguide layer, so that the divergence angle and the horizontal expansion angle of laser spots are increased, far-field images are distributed in an elliptical manner and meet Gaussian distribution, and the FFP with low aspect ratio is realized. The quality of light spots and light