Efficient Raman Amplification in Cladding-Pumped Silicon Waveguides

In this paper, we showed that the maximum achievable total gain of silicon Raman amplifiers can be significantly increased by injecting the pump power into a surrounding cladding instead of directly into the silicon core. The underlying principle is that the pump power is guided primarily in an optically linear cladding surrounding the silicon core and thus propagates relatively unimpaired by free-carrier absorption. This permits longer amplifier lengths and higher pump powers, which leads to a larger possible total gain