1 华中科技大学光学与电子信息学院，湖北 武汉 430074
2 华中科技大学无锡研究院，江苏 无锡 214174
随着激光雷达、引力波探测和光学原子钟等新技术的兴起和研究的不断深入，光学精密测量覆盖的应用领域的广度和深度都在拓展，传统自由运转的激光器其稳定性难以满足高精密测量的应用要求。超窄线宽、超低噪声和长期稳定的光源已成为该领域迫切追求的目标。光纤激光器具备结构紧凑、易于集成化和极限线宽窄等特点，通过噪声抑制和稳频技术输出超稳定、超窄线宽激光，近年来逐渐成为热点研究方向。本文从光纤激光器的噪声理论出发，介绍了光纤激光器的噪声来源、分类及测试方法，基于噪声理论，分类总结了光纤激光器强度噪声和频率噪声不同抑制技术的原理、发展历程及现阶段进展，并对窄线宽光纤激光器的发展趋势做了展望。
激光器 超窄线宽激光 光纤激光器 噪声抑制 稳频技术 激光与光电子学进展
2023, 60(15): 1500002
Author Affiliations
Abstract
1 School of Optical and Electronic Information, NGIA, Huazhong University of Science and Technology, Wuhan 430074, China
2 Shenzhen Techwinsemi Optoelectronic Co., Ltd., Shenzhen 518000, China
3 Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai Institute for Advanced Communication and Data Science, Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication, Shanghai University, Shanghai 200444, China
4 Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET, UK
We report the observation of second order Bragg resonance (2nd-OBG) produced by tilted fiber gratings (TFGs) fabricated using phase mask UV inscription. The theoretical analysis has revealed that the generation of high order Bragg resonance of gratings is induced by a square-shape refractive index profile, which is caused by over-saturated UV exposure. In the experiment, we have studied the TFGs with different tilt angles under over-saturated UV exposure, in which all gratings have showed the 2nd-OBR, and the larger tilt angle of the grating has the stronger 2nd-OBR. When the tilt angle of the grating is , the Bragg resonance exhibits very strong polarization dependence, because the 2nd-OBR wavelength is located within the polarizing bandwidth of 45° TFG. Finally, we have demonstrated an erbium-doped fiber laser with degree of polarization, and, by applying mechanical stretching on the grating, a wavelength tunable laser output has been achieved. The output laser shows amplitude variation within 1 h continuous monitoring of the laser.
tilted fiber grating fiber laser Chinese Optics Letters
2022, 20(1): 012201
1 华中科技大学光学与电子信息学院, 湖北 武汉 430030
2 华中科技大学武汉光电国家研究中心, 湖北 武汉 430030
报道一种基于45°辐射倾斜光纤光栅(RTFG)的全光纤偏振相关器件。由于独特的偏振相关模式耦合特性,其可作为一种理想的全光纤起偏器、偏振相关耦合器、全光纤衍射器。基于体电流法建立倾斜光纤光栅的偏振耦合理论,从理论和实验角度系统地分析45° RTFG的偏振辐射耦合、衍射分光及偏振特性。仿真结果和实验结果表明,45° RTFG的透射和辐射有良好的偏振功能。一根长度为24 mm的45° RTFG在波长为1550 nm处的偏振消光比(PER)为22 dB,3 dB带宽超过300 nm。通过制备不同长度的45° RTFG,可以实现具有不同PER的光栅。光栅的辐射模沿角向呈准高斯分布,沿轴向呈指数衰减分布,并且其空间衍射角色散约为0.054 (°)/nm。实验结果与理论结果完全匹配,45° RTFG具有潜在的应用前景。
光纤光学 光纤器件 倾斜光纤光栅 光纤衍射器件 光纤偏振器件 光学学报
2020, 40(23): 2306003
邢志坤 1,2,3宋青果 1,2,3牟成博 4,5,6闫志君 1,2,3,*[ ... ]刘德明 1,2,3
1 华中科技大学光学与电子信息学院, 湖北 武汉 430074
2 华中科技大学武汉光电国家研究中心, 湖北 武汉 430074
3 华中科技大学下一代互联网接入系统国家工程实验室, 湖北 武汉 430074
4 上海大学特种光纤与光接入网重点实验室, 上海 200444
5 上海大学上海先进通信与数据科学研究院, 上海 200444
6 上海大学特种光纤与先进通信国际合作联合实验室, 上海 200444
提出一种基于45°倾斜光纤光栅(45°-TFG)辐射模的线偏振光纤激光器。利用环形谐振腔结构和光纤布拉格光栅,搭建了基于45°-TFG辐射模的线偏振调谐光纤激光器,首次实现了基于TFG辐射模的全光纤单偏振激光输出。实验结果显示,当输入泵浦光功率大于24 mW时,可实现稳定的激光输出,输出激光的中心波长为1553.45 nm,3 dB带宽为0.05 nm,偏振度高达99.8%,激光器系统的斜率效率为10.79%。同时,利用布拉格光纤光栅的温度敏感特性,实现了激光器波长输出从1553.21 nm到1554.03 nm的调谐,调谐灵敏度为11.37 pm/℃。
激光器 光纤激光器 光纤光栅 辐射模 线偏振光纤激光器 中国激光
2020, 47(12): 1201007
Author Affiliations
Abstract
1 School of Optical and Electronic Information, NGIA, Huazhong University of Science and Technology, Wuhan 430074, China
2 Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
3 Faculty of Informatics, Electronics and Communications, Universidad de Panamá, Panama City, Republic of Panama
We proposed a hybrid tilted fiber gratings (polarizing grating and tilted fiber Bragg grating)-based surface plasmon resonance (SPR) sensor. The hybrid tilted fiber grating, consisting of a polarizing grating and tilted fiber Bragg grating (TFBG), is fabricated in a single-mode fiber in series by using a UV-inscription technique, in which the TFBG could generate a dense cladding mode resonance to excite SPR and the polarizing grating could filter out the S-polarization cladding mode of the TFBG. Such proposed hybrid tilted fiber gratings could greatly simplify the interrogation system of the TFBG-based SPR sensor. The experiment results showed that the hybrid tilted fiber gratings-based SPR sensor has the refractive index sensitivity of 522.8 nm/RIU. Finally, by using the proposed sensor, we have achieved the hemoglobin concentration detection within a sensing range from 0.1 mg/mL to 1.0 mg/mL and the sensitivity of 8.144 nm/(mg/mL).
surface plasmon resonance tilted fiber grating biosensing Chinese Optics Letters
2020, 18(10): 100601
