Fiber quarter-wave plates and magneto-optical fibers are important components that greatly affect the sensitivity of fiber-optic current sensors. A Tb:YAG crystal-derived silica fiber (TYDSF) was fabricated using a laser-heating drawing technique. The linear birefringence of TYDSF was measured as by a microscope birefringence measurement instrument. A fiber quarter-wave plate was fabricated by TYDSF at 1310 nm, which produced circularly polarized light with a polarization extinction ratio of 0.34 dB. Additionally, the linear birefringence of TYDSF was decreased by 22% by annealing at 750°C for 7 h, and the Verdet constants of annealed TYDSF were measured to be 9.83, 6.67, and at 808, 980, and 1310 nm, respectively.Faraday effect linear birefringence fiber quarter-wave plate
Chinese Optics Letters
2023, 21(11): 110601
Optical fiber microresonators have attracted considerable interest for acoustic detection because of their compact size and high optical quality. Here, we have proposed, designed, and fabricated a spring-based Fabry–Pérot cavity microresonator for highly sensitive acoustic detection. We observed two resonator vibration modes: one relating to the spring vibration state and the other determined by the point-clamped circular plate vibration mode. We found that the vibration modes can be coupled and optimized by changing the structure size. The proposed resonator is directly 3D printed on an optical fiber tip through two-photon polymerization and is used for acoustic detection and imaging. The experiments show that the device exhibits a high sensitivity and low noise equivalent acoustic signal level of at 75 kHz that can detect weak acoustic waves, which can be used for underwater object imaging. The results demonstrate that the proposed work has great potential in acoustic detection and biomedical imaging applications.
2023, 11(5): 780
2023, 50(10): 1006003
为实现大气污染物中氨气（NH3）的快速、准确测量，本文提出了一种基于氧化锌（ZnO）涂层单模-无芯-单模（SNS）光纤结构的高灵敏度NH3传感器。该传感器利用的是ZnO膜层吸附NH3后自身折射率改变，进而导致无芯光纤干涉谱谐振波长发生变化的特性。通过建立NH3体积分数与谐振波长偏移量的关系，最终实现了NH3体积分数的测量。本文基于模式传输理论对ZnO涂层SNS传感器的光谱特性进行了仿真，仿真结果显示：当ZnO膜层的折射率从1.929变化至1.889时，60 nm和130 nm ZnO膜厚下SNS传感器的灵敏度分别为11.8 nm/RIU和28.6 nm/RIU。制备了ZnO膜厚分别为60 nm和130 nm的SNS传感器，其在NH3体积分数为0~42.0×10-6环境下的灵敏度相差不大，这主要是由ZnO对NH3的吸附饱和引起的。进一步分析获得60 nm ZnO膜厚下SNS传感器的平均灵敏度为16.87×106 pm，检测限为6.6×10-6，响应时间和恢复时间分别为70 s和90 s。随着温度由16.5 ℃升至56 ℃，该传感器对NH3的检测灵敏度从17.96×106 pm降低至7.57×106 pm，温度和时间对检测限的影响分别为0.0237×10-6 ℃-1和0.026×10-6 d-1，该传感器具有较好的稳定性。传感器 无芯光纤 氧化锌 氨气测量 温度 sensor no-core fiber zinc oxide ammonia measurement temperature
2023, 50(10): 1006006
2023, 60(7): 0722001
We fabricate a high-performance Bi/Er/La co-doped silica fiber with a fluorescence intensity of and a gain coefficient of 1.9 dB/m. With the utilization of the fiber as a gain medium, a linear-cavity fiber laser has been constructed, which exhibits a signal-to-noise ratio of 74.9 dB at 1596 nm. It has been demonstrated that the fiber laser has a maximum output power of 107.4 mW, a slope efficiency of up to 17.0%, and a linewidth of less than 0.02 nm. Moreover, an all-fiber single-stage optical amplifier is built up for laser amplification, by which the amplified laser power is up to 410.0 mW with pump efficiency of 33.8%. The results indicate that the laser is capable of high signal-to-noise ratio and narrow linewidth, with potential applications for optical fiber sensing, biomedicine, precision measurement, and the pump source of the mid-infrared fiber lasers.Bi/Er/La co-doped silica fiber high signal-to-noise ratio laser narrow linewidth
Chinese Optics Letters
2022, 20(5): 051402
对基于磁致折变效应的掺铒光纤磁场传感器的温度特性进行了理论分析和实验测量。理论上，基于密度泛函理论(Density Functional Theory，DFT)研究了温度对掺铒光纤磁致折变效应的影响，结果表明，温度升高会增大掺铒石英材料的原子磁矩，从而增强其磁致折变效应。实验上，基于磁致折变效应，以掺铒光纤作为Mach-Zehnder光纤干涉仪的传感臂，研制了磁场传感器，结果表明，干涉波谷的谐振波长随温度的升高发生红移，传感器的磁场灵敏度随之增加，16.7 ℃和43.5 ℃温度下传感器的灵敏度分别为12.63 pm/mT和25.53 pm/mT，温度变化会影响磁场的测量精度。传感器 磁致折变效应 掺铒光纤 温度特性 磁场传感 Mach-Zehnder干涉仪 sensors magneto-refractive effect Er-doped fiber temperature characteristic magnetic field sensing Mach-Zehnder interferometer
Optofluidic resonators are capable of characterizing various fluidic media. Here, we propose an optofluidic microbottle resonator (OFMBR) that is applied to generate pendant droplets, whose maximum mass is related to the liquid surface tension. Mass and type of droplets forming along the OFMBR stem can be monitored in real time by spectrum variation. As a pendant droplet grows, increased droplet gravity introduces a decreased coupling gap and compressive force between the tapered fiber and OFMBR, leading to a resonance wavelength shift. The operation mechanism of the proposed sensors is validated by theoretical simulation and experimental results. From the experimental spectra, a liquid mass sensor with maximum sensitivity of is obtained, and distilled water and alcohol can be identified. This scheme provides a new thread for droplet generation as well as fluidic properties characterization.
2022, 10(3): 03000662