Abstract

In a last decade, all-normal dispersion (ANDi) mode locked fiber lasers have attracted huge attention due to their superior power scalability [1]. The pulse energy of femtosecond fiber lasers have significantly increased thanks for it [2]. ANDi laser at the wavelength range of two micron, however, has not been reported so far, because standard silica fiber shows large negative material dispersion around the two micron wavelength range. Fluoride glass fibers (ZBLAN) have a much smaller negative material dispersion and can have a positive total dispersion around two micron wavelength range with waveguide dispersion. Here we have demonstrated the ANDi nonlinear polarization rotation (NPR) mode-locked Tm:ZBLAN fiber laser at two micron wavelength range. An output power of 63 mW at 70.6MHz repetition rate with cat-ear like shape spectrum of ~80 nm bandwidth were obtained. The output was compressed 106 fs by grating pair compressor.

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