High power side pumped unidirectional ring Yb-doped double-clad fiber laser

Summary form only given, as follows. High power compact solid-state lasers in the 1-1.1 /spl mu/m spectral range are of great interest for many applications involving optical pumping of either Raman lasers or Pr-doped fiber amplifiers. In this context we have built an all-fiber high power Yb-doped fiber laser in a unidirectional ring geometry. The fiber is 10 m long and has a double cladding allowing the use of high power semiconductor lasers as pumping sources by multimode propagation in the inner cladding. The experimental setup is shown. The pump is injected using the V-groove technique thus ensuring both a high launching efficiency and free fiber ends. This latter point is very convenient to make a fiber-ring laser. Our laser operates in the CW regime and the output power is about 1.8 W. The spectral width is below 0.5 nm. Let us mention that in a linear cavity or in a ring cavity the same fiber operates in self-pulsing regime generally attributed to Brillouin backscattering. The use of an optical isolator allows us to efficiently stabilize the laser. The insertion of a tuning element in the cavity is actually under investigation and should allow to obtain a spectral tunability over the range 1.05-1.1 /spl mu/m.