Abstract

Instead of using continuous-wave multi-wavelength Raman pumping,¹ one can temporally multiplex pump wavelengths in a backward- pumped Raman amplifier, as recently proposed by Mollenauer, Mamyshev, and Grant.⁴ The pump light is then only at a single wavelength at any location within the fiber, which eliminates nonlinear pump-to-pump interactions.^2,3 if the repetition rate of the periodic pump frequency pattern is sufficiently high, the time spent at a particular pump wavelength dictates the amount of Raman gain arising from that wavelength, and a counter-propagating signal does not experience any significant temporal gain variations. Using a pulsed, single-wavelength Raman pump (representing the worst-case scenario for time-division multiplexed Raman pumping) we quantify the temporal Raman gain variations associated with a certain pump pattern repetition rate.

© 2002 Optical Society of America