In this thesis, it mainly studies the performance characteristics of the bending losses in semiconductor waveguides and the quantum dots semiconductor optical amplifier. We used InP-subtract and InGaAlAs /InAlAs multiple quantum wells epitaxial wafer grown by MBE as our material(£fg=1.41£gm). We had successfully fabricated a series of bending strip-loaded waveguides. On the quantum dots semiconductor optical amplifier, symmetric InGaAlAs/GaAs quantum well structure is used to fabricate the optical waveguide. We have established an automatic optical measurement system to measure the device characteristics more accurately. Design respect of bending waveguide, we design a series of radius, is 60£gm, 80£gm, 110£gm, 170£gm,and 260£gm respectively, and utilize Fabry-Perot resonant, measurement and estimate the loss of bending waveguide in quantity. We find the bending waveguide loss as radius for 260£gm and contain deeply etching process was quite equal to straight waveguide loss. On the quantum dots semiconductor optical amplifier, we design a single mode waveguide and a broad area waveguide to compare the difference of their electron-hole combination situation. A single mode waveguide with longer cavity length had better combination situation than shorter (C311 of cavity length 4000£gm ,0.00066£gW *A/cm2). And the broad area waveguide had more better combination situation to single mode waveguide (C311 of cavity width 150£gm, length 4000£gm , 0.0966£gW *A/cm2). For the gain to the pump signal, C311 singe mode waveguide (emission peak:1211nm,pump signal:1260nm) could get a gain about 3.56dB¡Fand C374 singe mode waveguide (emission peak:1255nm,pump signal:1260nm) could get a gain about 6.1dB.