The invention discloses a
semiconductor optical amplifier, and especially relates to a GaAs-based
semiconductor optical amplifier having a parabola-shaped curved-surface
waveguide structure. Material of the
semiconductor optical amplifier is a GaAs-based
material system. An N-type AlxGa1-xAs buffer layer, an N-type AlGaAsSb
lower limit layer, an N-type N-AlxGa1-xAs lower
waveguide layer, an InxGa1-xAs
quantum well active region, a P-type AlxGa1-xAs upper
waveguide layer and a P-type AlGaAsSb upper limit layer are epitaxially prepared on an N-type GaAs substrate in sequence. The upper waveguide layer of the semiconductor optical
amplifier is in the parabola-shaped curved-
surface structure; such structure can enable a parabola-shaped curved-surface tip to have higher
photon density, thereby improving
mode volume of the semiconductor optical
amplifier and enabling the semiconductor optical
amplifier to have higher
gain; and meanwhile, the parabola-shaped curved-surface waveguide structure facilitates compressing
divergence angle of the semiconductor optical amplifier, thereby realizing high-
power output and improving
fiber coupling efficiency. The parabola-shaped curved-
surface structure of the upper waveguide layer of the semiconductor optical amplifier is prepared through
electron beam
lithography or ultra-violet
lithography, and then, through a dry method and wet method combined
etching process.