Abstract

Raman amplification is a useful tool in extending the span lengths and the capacity of a transmission system.¹ An advantage of Raman scattering is that a broad flat gain can be achieved by using pumps at several different wavelengths and optical powers.^2,3 This eliminates the need for expensive and loss inducing gain flattening filters. Multiple-wavelength Raman fiber lasers (MWRFL) are potential Raman pump sources.^4–7 These lasers simultaneously emit depolarized radiation at several wavelengths from a single cavity, as compared to multiplexing together several semiconductor lasers or Raman fiber lasers. Recently a practical three-wavelength MWRFL (3λRFL) was demonstrated that exhibits a 38% 1100 nm to 14xx nm conversion efficiency.^6,7 This device varies the reflectivity of the cavity output coupler (OC) grating by an applied voltage to control the amount of power emitted at a given wavelength. Relative intensity noise (RIN) measurements demonstrated good stability.⁷ However, the interdependence of the optical powers at different wavelengths in the single cavity laser suggests that proper power partitioning is a potentially complex problem.

© 2002 Optical Society of America