Pal Atasi, Sen Ranjan, Bremer Kort, Yao Shuang, Lewis Elfed, Sun Tong, Grattan Kenneth T V
Fiber Optics & Photonics Division, Council of Scientific & Industrial Research-Central Glass & Ceramic Research Institute, Kolkata, India.
Appl Opt. 2012 Oct 10;51(29):7011-5. doi: 10.1364/AO.51.007011.
A stable and tunable thulium-doped "all-fiber" laser offering a narrow linewidth has been created specifically to act as a compact and simple laser source for gaseous CO(2) detection. This has been done through a careful design to match the laser output wavelengths to the CO(2) absorption lines at 1.875 and 1.997 μm, respectively. A sustainable output power of 11 mW over a tuning range of 7 nm has been obtained by using a combination of a high-reflective fiber Bragg grating with a low-reflective broadband mirror, fabricated at the end of the fiber through silver film deposition. The tuning was achieved using the relaxation-compression mechanism of the fiber Bragg grating, which formed an integral part of the laser resonant cavity. A fiber Bragg grating at 1.548 μm was utilized as a wavelength reference to monitor the tuning of the laser output over the 2 μm wavelength range with a simple and inexpensive interrogator, to avoid the use of an expensive optical spectrum analyzer and to facilitate "in-the-field" operation. This "all-fiber" laser resonator has been shown to be superior in terms of laser tuning range, output power, and linewidth compared to that created with a fiber Bragg grating pair, which was limited by the nonuniform strain transfer to both fiber Bragg gratings.
一种稳定且可调谐的掺铥“全光纤”激光器已被制造出来，其具有窄线宽，专门用作气态二氧化碳检测的紧凑且简单的激光源。这是通过精心设计实现的，使激光输出波长分别与二氧化碳在1.875微米和1.997微米处的吸收线相匹配。通过将高反射光纤布拉格光栅与低反射宽带镜相结合，在光纤末端通过银膜沉积制造，在7纳米的调谐范围内获得了11毫瓦的可持续输出功率。调谐是利用光纤布拉格光栅的弛豫 - 压缩机制实现的，该机制是激光谐振腔的一个组成部分。在1.548微米处的光纤布拉格光栅被用作波长参考，通过一个简单且廉价的询问器监测激光输出在2微米波长范围内的调谐，以避免使用昂贵的光谱分析仪并便于“现场”操作。与由光纤布拉格光栅对构成的激光器相比，这种“全光纤”激光谐振腔在激光调谐范围、输出功率和线宽方面表现更优，后者受限于向两个光纤布拉格光栅的不均匀应变传递。
