A widely wavelength tunable mode locked Er-doped fiber laser oscillator based on nonlinear polarization rotation (NPR) effect was demonstrated. By intentionally introducing a position-and-width adjustable slit and a pair of reflective gratings into the cavity, which worked as a wavelength and bandwidth tunable spectral filter, continuous wavelength tunable mode locked operation from 1532 nm to 1594 nm was achieved, corresponding to a tuning range of 62 nm, which is a new record for mode locked continuously wavelength-tunable single mode Er-doped fiber oscillators based on nonlinear polarization rotation, to the best of our knowledge. During the wavelength tuning, the pulse durations for different wavelengths changed slightly and closed to the Fourier-transform limit. The signal-to-noise ratio (SNR) of the radio frequency (RF) spectrum of the output pulses is higher than 89 dB over the entire wavelength tuning range, superior to the typical SNR of 50–70 dB reported in most papers. In addition, the pulse duration could be tuned from 904 fs to 1339 fs by adjusting the width of the slit, for which the corresponding spectral bandwidth changed from 3.4 nm to 1.7 nm.

演示了基于非线性偏振旋转（NPR）效应的宽波长可调谐锁模掺Er光纤激光器。通过有意地在腔中引入一个位置和宽度可调的狭缝和一对反射光栅，它们用作波长和带宽可调光谱滤波器，实现了从1532 nm到1594 nm的连续波长可调锁模操作，相当于据我们所知，它的最大调谐范围是62 nm，这是基于非线性偏振旋转的锁模连续波长可调单模掺Er光纤振荡器的新记录。在波长调谐期间，不同波长的脉冲持续时间略有变化，并接近傅里叶变换极限。在整个波长调谐范围内，输出脉冲的射频（RF）频谱的信噪比（SNR）高于89 dB，优于大多数论文中报告的典型SNR 50-70 dB。另外，可以通过调节狭缝的宽度将脉冲持续时间从904 fs调整为1339 fs，为此，相应的光谱带宽从3.4 nm更改为1.7 nm。