Abstract In this paper, we present a simple compact and low threshold laser that has characteristics of Q-switched and multi-wavelength oscillation simultaneously. Multi-wavelength Q-switched oscillation is realized by inserting a Sagnac filter as a multi-wavelength filter and a section of unpumped erbium-ytterbium co-doped fiber (EYDF) into the laser cavity as a saturable absorber (SA). The characteristics of multi-wavelength Q-switched fiber laser affected by wavelength separation of filter and pump power are investigated. The number of Q-switched wavelengths increases and the wavelength separation of the laser reduces with wavelength separation of the filter decreasing. Stable multi-wavelength oscillations at wavelength separation of 0.4–0.8 nm were obtained by increasing the length of polarization maintaining fiber (PMF) in the Sagnac filter. Moreover, the number of wavelengths and wavelength separation are increased by increasing the pump power when the filter is fixed. Further, the multi-wavelength laser is verified to have Q-switched properties at each wavelength, which is filtered from laser output through a narrow-band tunable filter outside of the cavity.

中文翻译：

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改变滤光片波长间隔表征多波长调Q光纤激光器

摘要 在本文中，我们提出了一种简单的紧凑型低阈值激光器，它同时具有调Q 和多波长振荡的特性。多波长调Q振荡是通过将萨格纳克滤波器作为多波长滤波器和一段未泵浦的铒镱共掺杂光纤（EYDF）插入激光腔作为可饱和吸收体（SA）来实现的。研究了滤波器波长分离和泵浦功率对多波长调Q光纤激光器特性的影响。随着滤光片波长间隔的减小，调Q波长的数量增加，激光器的波长间隔减小。通过增加 Sagnac 滤波器中保偏光纤 (PMF) 的长度，可以获得波长间隔为 0.4-0.8 nm 的稳定多波长振荡。此外，当滤波器固定时，通过增加泵浦功率来增加波长数和波长分离。此外，多波长激光器被证实在每个波长都具有调Q特性，通过腔外的窄带可调滤波器从激光输出中过滤掉。