The invention is an optical apparatus and method of fabrication wherein an optical device such as a semiconductor laser includes a grating and a waveguide optically coupled to the grating. At least a portion of the waveguide coupled to the grating has a width which varies along the length of the waveguide in such a manner as to broaden the spectral line width of light output from the device. The width can be varied according to linear, sinusoidal or saw-tooth functions. A broadened line width permits pumping of a Raman amplifier at a high power without inducing any significant Brillouin Scattering.