A silicon photonics platform is promising for manufacturing compact and low cost optical transceivers. Ge photodetectors have been developed by the epitaxial growth on Si. The next challenge is the on-silicon integration of group III-V semiconductors for laser diodes and high efficiency modulators. In this work, the III-V semiconductors are integrated on a silicon-on-insulator wafer by using the wafer bonding processes. We review the Ge-on-Si photodetectors and recently developed high efficiency III-V-on-Si metal-oxide-semiconductor capacitor Mach-Zehnder modulators.