基于锥形光纤的可调谐光纤激光器

Tunable Fiber Lasers Based on Tapered Fiber

利用几何光学理论分析了锥形光纤中传输光线模式的变化,得到锥形光纤锥腰直径在1.135~60μm范围内时可实现多模传输的结果。采用熔融拉锥系统制备不同直径的锥形光纤,运用Origin软件拟合得出锥形光纤半径随拉伸长度的变化关系,在给定条件下,拉锥时间为95s时,获得锥腰直径为2.475μm的锥形光纤。运用RSoft公司的BeamPROP模块对直径为2.475μm锥形光纤的传输性能进行了模拟,同时采用放大自发辐射(ASE)光源作为输入光源,选取1530~1580nm波段,测量了锥形光纤输出光功率随波长的变化关系。将锥形光纤接入环形腔,通过偏振控制器改变腔内信号光的偏振态,实现了1563.828~1565.444nm范围内的波长可调谐,边模抑制比为51.4dB,并得到波长间隔最大为1.48nm的双波长输出,边模抑制比为49.8dB。

The geometrical optics theory is adopted to analyze the change of light transmission mode in tapered fiber, and multimode transmission is achieved when tapered fiber diameter is in the range of 1. 135-60/~m. Tapered fibers are fabricated with fused biconical taper system. The relationship between the tapered fiber radius and the stretching length is obtained by Origin software. Under the given conditions, tapered fiber with waist diameter of 2. 475 #m is fabricated when the stretching time is 95 s. The transmission performances of tapered fiber with waist diameter of 2. 475 /~m are simulated by the BeamPROP module of RSoft. We use amplified spontaneous emission （ASE） optical source to measure the output optical power change with wavelength in 1530-1580 nm. The tapered fiber is inserted into the ring cavity, and the polarization state of the signal light in the cavity is changed by the polarization controller to realize wavelength tunable in the range of 1563. 828-1565. 444 nm. The side-mode suppression ratio is 51.4 dB, and the double wavelength output with a maximum wavelength interval of 1.48 nm is achieved while the side-mode suppression ratio is 49.8 dB.