Passive mode-locked Er-doped fiber laser pulse generation based on titanium disulfide saturable absorber

Abstract

In this study, titanium disulfide (TiS 2 ) polyvinyl alcohol (PVA) film-type saturable absorber (SA) is synthesized with a modulation depth of 5.08% and a saturable intensity of 10.62 MW/cm 2 by liquid-phase exfoliation and spin-coating methods. Since TiS 2 -based SA has a strong nonlinear saturable absorption property, two types of optical soliton were observed in a mode-locked Er-doped fiber laser. When the pump power was raised to 67.3 mW, a conventional mode-locked pulse train with a repetition rate of 1.716 MHz and a pulse width of 6.57 ps was generated, and the output spectrum centered at 1556.98 nm and 0.466 nm spectral width with obvious Kelly sidebands was obtained. Another type of mode-locked pulse train with the maximum output power of 3.92 mW and pulse energy of 2.28 nJ at the pump power of 517.2 mW was achieved when the polarization controllers were adjusted. Since TiS 2 -based SA has excellent nonlinear saturable absorption characteristics, broad applications in ultrafast photonic are expected. 本文采用液相剥离法和旋涂法合成调制深度为5.08%、 饱和强度为10.62 MW/cm 2 的二硫化钛聚乙烯醇薄膜型可饱和吸收体. 由于二硫化钛可饱和吸收体具有很强的非线性饱和吸收特性, 在掺铒锁模光纤激光器中观测到两种类型的光孤子. 当泵浦功率达到67.3 mW时, 产生重复率为1.716 MHz、 脉宽为6.57 ps的传统锁模脉冲串, 其输出光谱中心为1556.98 nm、 半高全宽为0.466 nm, 且有明显对称的Kelly边带. 通过调整偏振控制器, 得到另一种锁模脉冲, 在517.2 mW泵浦功率下, 其最大输出功率为3.92 mW, 脉冲能量为2.28 nJ. 实验证明层状二维材料二硫化钛具有优异的非线性饱和吸收特性, 在超快光子学领域具有广阔应用前景.