TTG-DFB laser diode on a doped substrate (1) with a strip-like layer structure, which comprises an intermediate layer (5) between an active layer (4) and a tuning layer (6), in which a cladding layer (8 ) which is doped for the same conductivity type as the substrate (1) and which is electrically conductively connected to the substrate (1) by an interruption (81) of the layers underneath, in which in each case in this cladding layer (8) reaching to the surface and doped in the opposite direction, an upper region (11) above the layer structure and a lateral region (9) separate therefrom, which is electrically conductively connected via a lower cladding layer (3) to the side of the layer structure facing the substrate (1), are formed in which contact layers (10, 12) and contacts (14, 15) are applied to the upper region (11) and on the lateral region (9) and be i a contact (16) is applied to the substrate (1) so that a separate current injection through the intermediate layer (5) into both the active layer (7) and the tuning layer (6) is possible. IMAGE展开