双波长可切换方波类噪声锁模线形光纤激光器

采用非线性偏振旋转锁模技术，在线形腔光纤激光器获得双波长可切换方波类噪声锁模。通过调节腔参数，激光器在波长1530 nm和1563 nm处分别获得可切换单波长方波类噪声锁模，最大脉冲宽度分别为12 ns和26 ns,腔内最大的脉冲能量分别可达14.7 nJ和45.6 nJ。此外激光器还可在这两波长处实现双波长类噪声锁模，锁模脉冲呈阶梯形，最大脉宽为5 ns,阶梯形脉冲的产生主要源于不同中心波长处的方波脉冲叠加。实验结果有助于进一步理解线形腔光纤激光器中方波类噪声的产生机理和特性，并为多波长高能量光源的设计提供参考。

Switchable dual wavelength square noise like pulse in a linear cavity fiber laser

A switchable dual wavelength square noise like pulse is achieved from the linear cavity mode locked fiber laser based on nonlinear polarization rotation.By regulating the cavity parameters,square noise like mode locking at 1530 nm and 1563 nm are obtained from the fiber laser,achieving pulse durations of up to 12 ns and 26 ns,respectively.The corresponding maximum intracavity pulse energy can reach 14.7 nJ and 45.6 nJ,respectively.Additionally,the dual wavelength noise like mode locking can be also realized at the two wavelengths.The output pulse exhibits a step like shape with the pulse width of 5 ns,which could be attributed to the superposition of the square pulses at different wavelengths.The experimentaal results are helpful to further reveal the formation mechanism and characteristics of square noise like pulses in the linear cavity fiber laser,and provide a reference for the design of multi wavelength laser source with high energy.