Broadband 2  μm amplified spontaneous emission of Ho/Cr/Tm:YAG crystal derived all-glass fibers for mode-locked fiber laser applications.

Broadband similar to 2 mu m amplified spontaneous emissions with a full width at half-maximum (FWHM) varying from similar to 206 to similar to 234 nm were obtained from the Ho/Cr/Tm:yttrium aluminum garnet (YAG) crystal derived fibers, which were drawn using a molten core method. The core-cladding structure of the as-drawn fibers was preserved completely, and the core was found to be amorphous. What is more, an all-fiber-integrated passively mode-locked laser based on an 8 cm long Ho/Cr/Tm:YAG crystal derived all-glass fiber was built which, to the best of our knowledge, is the first demonstration of a mode-locked fiber laser in a similar YAG derived fiber. The mode-locked pulses operate at 1.95 mu m with duration of similar to 118 ps, and the repetition rate is similar to 9.5 MHz. Limited by the bandwidth of the fiber grating used in the laser cavity, the mode-locking spectrum has a relatively narrow FWHM of similar to 0.09 nm. These results suggest that the broadband YAG crystal derived all-glass fibers are promising for ultrafast fiber lasers applications. (C) 2019 Optical Society of America