Mode-Locked Erbium-Doped Fiber Lasers Using 45° Tilted Fiber Grating

We have systematically studied the 45° tilted fiber grating (45TFG) as a functional device for erbium-doped fiber laser (EDFL) mode locking. A number of 45TFGs with different polarization-dependent loss (PDL) have been fabricated. Mode-locked (EDFL) using these devices have been characterized in terms of threshold, pulse duration, signal-to-noise ratio, and spectral width. Our results show that a 45TFG with higher PDL could achieve better laser results. By using a 45TFG with 24 dB PDL, the mode-locked laser has 8.1% conversion efficiency and a threshold of 200 mW.