A laser diode has a first n-conducting cladding layer, a first n-conducting waveguide layer arranged therein, an active layer is suitable for generating radiation arranged on the first waveguide layer, a second p-conducting waveguide layer, arranged on the active layer, and a second p-conducting cladding layer, arranged on the second waveguide layer the sum of the layer thickness of the first waveguide layer, the layer thickness of the active layer and the layer thickness of the second waveguide layer is greater than 1 μm and the layer thickness of the second waveguide layer is less than 150 nm. The maximum mode intensity of the fundamental mode is in a region outside the active layer, and the difference between the refractive index of the first waveguide layer and the refractive index of the first cladding layer is between 0.04 and 0.01.