Silicon Photonics

Recent work by Cornell University and others have shown that light amplification and emission can be achieved by using silicon as a nonlinear optical material. One of the primary reasons for this is that the refractive index for silicon is very high, and thus extremely compact waveguides can be created that confine light very tightly. This results in the ability of the devices to operate at very low powers. While this is certainly an importan property, these tightly confining waveguides offer the ability to use the waveguide dispersion to conserve momentum (i.e., phase match) of nonlinear processes which greatly improves the efficiency. The authors have applied this dispersion control to achieve amplification over extremely large bandwidths. One could then envision using a single single micron-size device for amplifying the entire telecom bandwidth. Based on such a device, an ultrasmall device that can emit light over very broad range of frequencies was also demonstrated. The light emitted is laser-like and can be used as a as source for lighting up silicon chips.