A method of manufacturing a semiconductor laser, comprising: a) providing a substrate; b) growing an n-blocking layer over the substrate; c) growing an n-cladding layer over a growth time, with a higher index than the n-blocking layer, over the n-blocking layer; d) depositing an active region including a quantum well sandwiched by two waveguide layers, on the n-cladding layer; e) depositing a p-cladding layer over the active region; wherein step c) and e) include selecting a refractive index of the n-cladding and the p-cladding layer, so that in operation, a lasing optical mode of the semiconductor laser is asymmetric, the majority of the lasing optical mode shifting towards the n-cladding layer, with a peak point of the lasing optical mode remaining inside the active region, wherein the n-cladding layer includes a portion wherein an optical power density of the lasing optical mode is less than 0.03% of the optical power density at the peak point of the lasing optical mode; wherein in step c), a thickness of the n-cladding layer is selected between 3 micrometers and 6 micrometers, to ensure that a vertical far-field divergence angle of the lasing optical mode is under 17°; wherein in step e), the refractive index of the p-cladding layer is lower than the refractive index of the n-cladding layer; and characterized in that, the refractive index of the n-cladding layer is lower than the refractive indices of the quantum well and the waveguide layers. a) providing a substrate; b) growing an n-blocking layer over the substrate; c) growing an n-cladding layer over a growth time, with a higher index than the n-blocking layer, over the n-blocking layer; d) depositing an active region including a quantum well sandwiched by two waveguide layers, on the n-cladding layer; e) depositing a p-cladding layer over the active region; wherein step c) and e) include selecting a refractive index of the n-cladding and the p-cladding layer, so that in operation, a lasing optical mode of the semiconductor laser is asymmetric, the majority of the lasing optical mode shifting towards the n-cladding layer, with a peak point of the lasing optical mode remaining inside the active region, wherein the n-cladding layer includes a portion wherein an optical power density of the lasing optical mode is less than 0.03% of the optical power density at the peak point of the lasing optical mode; wherein in step c), a thickness of the n-cladding layer is selected between 3 micrometers and 6 micrometers, to ensure that a vertical far-field divergence angle of the lasing optical mode is under 17°; wherein in step e), the refractive index of the p-cladding layer is lower than the refractive index of the n-cladding layer; and wherein step c) and e) include selecting a refractive index of the n-cladding and the p-cladding layer, so that in operation, a lasing optical mode of the semiconductor laser is asymmetric, the majority of the lasing optical mode shifting towards the n-cladding layer, with a peak point of the lasing optical mode remaining inside the active region, wherein the n-cladding layer includes a portion wherein an optical power density of the lasing optical mode is less than 0.03% of the optical power density at the peak point of the lasing optical mode; wherein in step c), a thickness of the n-cladding layer is selected between 3 micrometers and 6 micrometers, to ensure that a vertical far-field divergence angle of the lasing optical mode is under 17°; wherein in step e), the refractive index of the p-cladding layer is lower than the refractive index of the n-cladding layer; and