A narrow line distributed feedback (DFB) fiber laser based on a 16 mm long Bragg grating, inscribed in a purpose-made strongly activated and highly photosensitive silica fiber, was fabricated and tested. A fiber preform synthesized by means of surface-plasma chemical vapor deposition (SPCVD), and a standard Bragg grating writing technology using an ArF excimer laser and a π-shifted phase mask, were applied to fiber drawing and grating writing, respectively. A single-mode generation regime of the DFB laser core-pumped at a wavelength of 976 nm was obtained, the measured linewidth being less than 8 kHz.