Filter fiber for use in Raman lasing applications and techniques for manufacturing same

A method for making a filter fiber, comprising:

• providing an optical waveguide having a refractive index variation that is structured to provide the fiber, over a wavelength operating range, with an effective area supporting multiple Stokes shifts and with a negative dispersion value at a target wavelength within the wavelength operating range,
• structuring the fiber to have a refractive index variation that provide the fiber with a finite LP01 cutoff at a wavelength longer than the target wavelength, whereby the LP01 cutoff wavelength provides a disparity, for a selected bending diameter, between macrobending losses at the target wavelength and macrobending losses at wavelengths longer than the target wavelength,
• whereby Raman scattering is frustrated at wavelengths longer than the target wavelength.