| 摘要 |
PURPOSE:To converge an output beam in an upward direction by a method wherein a diffraction grating is made to be a shape partially resembling a ripple whose cycle becomes short with a distance becoming more distant from a beam radiation end of an active layer, which is curved to be a concentrically circular shape or a shape resembling a concentric circle and whose center is situated near the beam radiation end. CONSTITUTION:A diffraction grating 7 is formed partially on an n-InP substrate 1 ; a waveguide layer 10, an active layer 4, a clad layer 5 and a contact layer 6 are laminated on it. In succession, a mesa stripe 13 is formed; the surface of the waveguide layer 10 excluding this part is exposed; a convergence grating coupler 11 is formed. The convergence grating coupler 11 is constituted in such a way that its cycle becomes small with a distance becoming more distant from the active layer 4 and that it is curved to be a circular arc whose center is situated near a beam radiation end of the active layer 4. Lastly, an electrode 8 is formed; a dielectric multilayer film 12 is formed on an end face of a laser; a desired semiconductor laser is obtained. As a result, a laser output beam radiated upward can be converged down to a spot of about 5mum. |
