Abstract

High power compact solid-state lasers in the 1-1 1 µm 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 clad allowing the use of high power semiconductor lasers as pumping sources by multimode propagation in the inner cladding (fig 1). The experimental setup is shown in figure 1 The pump is injected using the V-groove technique [1] 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 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 [2] 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 µm

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