Wavelength-tunable Q-switched fiber laser based on a 45° tilted fiber grating

Abstract

A continuously tunable Q-switched all-fiber Er-doped laser based on a 45° tilted fiber grating and tunable bandpass filter is demonstrated. The 45° tilted fiber grating is used to achieve the nonlinear polarization rotation (NPR) along with two polarization controllers (PCs), Q-switching is realized due to the fact that the NPR effect induced intensity-dependent loss. Under the pump power of 655 mW, the Q-switched optical spectrum can be continuously tuned from 1512 nm to 1552 nm by simply rotating the tunable bandpass filter. During the wavelength tuning process, the average output power increases from 0.282 mW to 4.884 mW while the repetition rate enhances from 27.3 kHz to 119 kHz. To the best of our knowledge, this is the widest continuously tunable range of Q-switched fiber Lasers based on nonlinear polarization rotation effect and spectral bandpass filter.