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High power erbium doped fiber laser generating switchable radially and azimuthally polarized beams at 1.6 µm wavelength

An erbium-doped fiber laser cavity design is demonstrated to produce radially and azimuthally polarized beams. A c-cut calcite crystal is set within a three-lens telescope system in the laser cavity. Due to the birefringence of the crystal, radial and azimuthal polarizations are focused to different foci. The ray behavior through the crystal is discussed in details with birefringent ray tracing. By translating a collimation lens, one can select either the radial or the azimuthal polarization to lase in the cavity. The maximum output power obtained is about 140 mW for both polarizations.