基于ASE泵浦的1.7μm波段可调谐多波长拉曼光纤激光器实验研究

1.7μm Tunable Multi-Wavelength Raman Fiber Laser Based on Amplified Spontaneous Emission Pump

报道了一种输出波长为1.7μm波段的可调谐多波长拉曼光纤激光器。该激光器采用过滤的1550nm波段自发辐射源来作为泵浦源,从而避免受激布里渊散射。高非线性光纤和色散位移光纤作为非线性增益介质,从而获得峰值波长为1.7μm波段的增益谱。并采用一段未泵浦的掺铒光纤用于吸收增益谱中残余的泵浦光,所产生的增益谱由Sagnac环滤波器进行滤波。通过调节偏振控制器和放大自发辐射后端的可调谐滤波器,可以产生在1652.77nm和1686.20nm之间具有调谐范围大于33.4nm的单波长激光输出。单波长激光器的光谱3dB有效线宽为0.08nm。并且通过增加泵浦功率和调节Sagnac环滤波器实现多波长激光输出,双波长激光可以在1654.88nm到1664.60nm之间连续调谐。单波长和双波长激光的边模抑制比均大于45dB。

A simple tunable multi-wavelength Raman fiber laser with output wavelength near 1.7μm band is proposed and experimentally demonstrated.In this scheme,a 1550 nm band amplified spontaneous emission is used as the pump source and avoid stimulated Brillouin scattering.The dispersion shifted fiber and high nonlinear optical fiber are used as nonlinear gain to obtain the gain spectrum with peak wavelength near the 1.7μm band,and an unpumped erbium-doped fiber is used to absorb the remaining pump light in the gain spectrum.The gain spectrum is filtered by a Sagnac loop filter.We demonstrate the tuning capacities of single-wavelength over 33.4 nm between1652.77 nm and 1686.20 nm by adjusting the polarization controller and tunable filter on the back end of the amplified spontaneous emission.The 3 dB effective linewidth of single-wavelength laser is 0.08 nm.And by increasing the pump power and adjusting the Sagnac loop filter to achieve multi-wavelength laser output,the dualwavelength laser can be continuously tuned between 1654.88 nm to 1664.60 nm.The side mode suppression ratios of single-wavelength and dual-wavelength lasers are greater than 45 dB.