We present approximate analytical expressions describing nonlinear interaction of two optical waves copropagating inside a silicon waveguide in the presence of linear losses, stimulated Raman scattering, and free-carrier absorption. Our approach avoids the undepleted-pump approximation, which we show to be inadequate to describe accurately the Raman-gain process. Based on our calculations, we propose a new generalized definition for the effective length and show that it provides better insight into the impact of nonlinear absorption on Raman amplification in silicon waveguides.
© 2009 Optical Society of America
Original Manuscript: November 12, 2008
Revised Manuscript: December 19, 2008
Manuscript Accepted: December 19, 2008
Published: February 13, 2009
Ivan D. Rukhlenko, Malin Premaratne, Chethiya Dissanayake, and Govind P. Agrawal, "Continuous-wave Raman amplification in silicon waveguides: beyond the undepleted pump approximation," Opt. Lett. 34, 536-538 (2009)