The authors propose a new simple configuration for 1.24 and 1.48 µm Raman fibre lasers which are promising pumping sources for 1.31 µm Raman amplifiers and Er-doped fibre amplifiers, respectively. Efficient resonant conversion of CW 1.06 µm radiation to the first (1.24 µm) and second (1.48 µm) Raman Stokes in a phosphosilicate fibre is demonstrated for the first time.

We report a laser-diode-pumped 1407-nm Raman fiber laser with an output power of 1 W. In this three-cascaded cw Raman laser, based on a single active phosphorus-doped silica fiber, for the first time to the authors’ knowledge successive generation of Stokes components of essentially different frequency shifts (1330 and $490 {\mathrm{cm}}^{-1}$) has been realized. These Stokes components are associated with both constituents (${\mathrm{P}}_2{\mathrm{O}}_5$ and ${\mathrm{SiO}}_2$) of the fiber core glass.

Germania-glass-core silica-glass-cladding single-mode fibers ($\mathrm{\Delta }n$ as great as 0.143) with a minimum loss of 20 dB/km at $1.85 \mathit{\mu }\mathrm{m}$ were fabricated by modified chemical-vapor deposition. The fibers exhibit strong photorefractivity, with type IIa index modulation of $2\times {10}^{-3}$. A Raman gain of 300 dB/(km W) was determined at $1.12 \mathit{\mu }\mathrm{m}$. Only 3 m of such fibers is sufficient for constructing the 10-W Raman laser at $1.12 \mathit{\mu }\mathrm{m}$ with a 13-W pump at $1.07 \mathit{\mu }\mathrm{m}$.

An all-fiber $1.48‐\mathit{\mu }\mathrm{m}$ generator based on a laser-diode-pumped Yb-doped double-clad laser and a cascaded Raman wavelength converter has been developed. Second-order Raman Stokes radiation was generated in a phosphosilicate-fiber resonator formed by two pairs of Bragg gratings. A slope efficiency of the Raman converter of 48% with respect to the power emitted by the double-clad Yb laser has been achieved. We obtained an output power of 1 W at a slope efficiency of 34% with respect to the laser-diode array power, with a total optical-to-optical efficiency of 23%.

An all-fiber electrically tunable loss filter that is based on photoinduced long-period grating coated by Ti-Pt metal coating was developed and investigated. Maximum wavelength tuning of 11 nm with an applied power of 0.67 W was achieved for the HE17 cladding mode resonance peak.

This is the first report, to our knowledge, of refractive-index grating side writing in 10 mol. % GeO₂-doped fiber by the near-UV light of a cw ${\mathrm{Ar}}^{+}$ laser (333–364 nm). An induced-index magnitude as large as $1.9\times {10}^{-4}$ at $1.7\times {10}^5\mathrm{W}/{\mathrm{cm}}^2$ UV power density has been achieved. The observed gratings have exhibited the same temperature stability as gratings written by a KrF excimer laser (248 nm).