Li Xiaoyan, Zhang Peng, Wu Di, Han Kexuan, Tong Shoufeng, Jiang Huilin
Appl Opt. 2020 Apr 10;59(11):3458-3466. doi: 10.1364/AO.387225.
A single-/dual-pulse repetition rate variable supercontinuum (SC) light source (SLS) with a peak wavelength of around 1.7 µm (SLS around 1.7 µm) is proposed and experimentally demonstrated. In our scheme, a 1.5 µm modulated pump source included a laser and an intensity modulator (IM). The pump source can generate pulse trains with different repetitions and pulse durations. A 1 km high nonlinear fiber (HNLF) was used as the nonlinear gain medium. A picosecond-pulsed SC signal was obtained by pumping the HNLF, and a wavelength division multiplexer was used for filtering residual pump. Additionally, a Sagnac loop was applied to create a multiwavelength pulse SC light source. The generated SC source covered from 1.59 to 1.96 µm, and its peak wavelength was around 1.7 µm. The single-/dual-pulse train can be produced and switched by adjusting the direct current bias and radio frequency driving voltages of the input signal to the IM. When the repetition rate of the generated pulse train was between 170 MHz and 2 GHz, the pulse duration of the dual-pulse train was between 60 ps and 180 ps. Additionally, the duty cycle of the dual-pulse operation was 40%. The single pulse SLS, around 1.7 µm, can be a choice to improve optical coherence tomography (OCT) performance, and the dual-pulse source will be a reference for laser drilling applications.
提出并通过实验证明了一种峰值波长约为1.7 µm的单脉冲/双脉冲重复频率可变超连续谱（SC）光源（1.7 µm左右的SC光源）。在我们的方案中，一个1.5 µm的调制泵浦源包括一台激光器和一个强度调制器（IM）。该泵浦源可以产生具有不同重复频率和脉冲持续时间的脉冲序列。使用一根1 km长的高非线性光纤（HNLF）作为非线性增益介质。通过泵浦HNLF获得了皮秒脉冲SC信号，并使用一个波分复用器来滤除残余泵浦光。此外，应用一个萨格纳克环来产生多波长脉冲SC光源。所产生的SC光源覆盖范围为1.59至1.96 µm，其峰值波长约为1.7 µm。通过调整输入到IM的信号的直流偏置和射频驱动电压，可以产生并切换单脉冲/双脉冲序列。当所产生的脉冲序列的重复频率在170 MHz至2 GHz之间时，双脉冲序列的脉冲持续时间在60 ps至180 ps之间。此外，双脉冲操作的占空比为40%。1.7 µm左右的单脉冲SC光源可以作为提高光学相干断层扫描（OCT）性能的一种选择，而双脉冲光源将为激光钻孔应用提供参考。
