Effect of geometry and reverse bias on free carrier lifetime in p-i-n structured optical rib waveguide

The dependency of effective free carrier lifetime on the lateral dimensions of the Silicon on Insulator (SOI) p-i-n optical rib waveguide has been demonstrated. Effect of reverse bias on the same is also studied. Since carrier generation through two photon absorption is omnipresent in Si, the lifetime of the free carriers plays an important role in determining the net achievable Raman gain in SOI waveguides as it affects nonlinear absorption loss due to free carriers. A detailed analytical model has been derived for the assessment of effective lifetime of free carriers in reverse bias condition in various geometrical features of the waveguide.