An edge emitting semiconductor laser containing a plurality of monolithically integrated laser diodes (1, 2, 3). Each laser diode (1, 2, 3) contains an active zone (11, 12, 13), with the active zones (11, 12, 13) being in each case arranged between waveguide layers (6), the waveguide layers (6) in each case adjoining a cladding layer (7, 8) at a side remote from the active zone (11, 12, 13). The cladding layers (7, 8) comprise inner cladding layers (7), which are arranged above a bottommost active zone (11) and below a topmost active zone (13), and outer cladding layers (8) which are arranged below the bottommost active zone (11) or above the topmost active zone (13). The inner cladding layers (7) have a smaller thickness than the outer cladding layers (8).