Stimulated Raman scattering in silicon waveguides are attractive for optical amplification/lasing due to high Raman coefficient and high optical pump intensity in the small waveguide core. In this paper, we investigate the effect of two-photon absorption and free-carrier absorption for continuous-wave light propagation in submicron size silicon wire waveguides. We also show that if the waveguide lengths and pump powers are optimized, the net continuous-wave Raman gain and thus lasing activities in such waveguides without any additional free carrier extraction schemes is possible.
A rectangular-waveguide output UTC-PD module integrating a HEMT power amplifier has been developed for operation in the 125-GHz band. The fabricated module exhibits maximum output power of more than 14dBm with nearly flat frequency dependence in the 115-135GHz range. A 10-Gbit/s error-free wireless transmission at 125GHz with a minimum sensitivity of -34dBm for a bit-error-rate of 10-12 is also demonstrated using the fabricated module.