Patent ID: 8351111

Claim:
A light generation and amplification system, comprising: a length of laser-active filter fiber having a refractive index profile that suppresses unwanted Stokes orders at wavelengths longer than a target wavelength and having normal dispersion over an operating bandwidth, wherein the laser-active fiber provides a gain medium for a nested series of Raman cavities, separated in wavelength by approximately the respective Stokes shifts, wherein a first cavity in the nested series of cavities is a combined cavity that is configured to provide laser oscillation arising from a combination of ionic gain and feedback at a selected first wavelength, and to provide Raman gain to light at the first Stokes shift of the first wavelength when the light at the first wavelength has an intensity exceeding a Raman scattering threshold, wherein each successive Raman cavity in the nested series of Raman cavities is configured to provide Raman gain at each successive Stokes shift, whereby the nested series of Raman cavities provide a stepwise transition between the first wavelength and the target wavelength, and wherein an output coupler located at the filter fiber output end, is configured to provide output coupling out of the filter fiber of light at the target wavelength; and a pump power source for providing a pump power input into the filter fiber.