Author Affiliations
Abstract
1 Wuhan National Laboratory for Optoelectronics (WNLO) and National Engineering Laboratory for Next Generation Internet Access System, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
2 Department of Electronics and Information Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
In this Letter, a low-frequency acoustic sensor based on an extrinsic Fabry–Pérot (FP) interferometer with a silicon nitride (Si3N4) membrane is demonstrated. Using micromachining techniques, the 800 nm thick Si3N4 membrane is deposited on an 8 mm × 8 mm × 400 μm silicon (Si) substrate. All the assembly procedures of the sensor are focused on the substrate to avoid any damage to the membrane itself, compared to general membrane transfer methods. The frequency response of the proposed sensor is discussed theoretically and experimentally demonstrated. The sensor exhibits an excellent flat response to the tested acoustic frequency range of 1 Hz to 250 Hz. The phase sensitivity is around ?152 dB re 1 rad/μPa with sensitivity fluctuation less than 0.8 dB. The frequency response characteristic shows a promising potential of the sensor in low-frequency acoustic signal sensing applications.
acoustics fiber Fabry–Pérot interferometer low frequency membrane Chinese Optics Letters
2020, 18(10): 101201
Author Affiliations
Abstract
1 School of Optical and Electronic Information, National Engineering Laboratory for Next Generation Internet Access System, Huazhong University of Science and Technology, Wuhan 430074, China
2 Department of Electronics and Information Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
3 Yangtze Optics Electronics Co., Wuhan 430074, China
This Letter shows the Vernier effect based on two segments of PANDA polarization maintaining fiber (PMF), whose lengths are 28 and 23 cm, respectively. The two PMFs are spliced together, and the angle between the fast axes is set to 45°. This cascaded PMF is inserted in a Sagnac loop to form an interferometer that can generate the Vernier effect. The spectrum consists of finesse fringe and envelope and realizes simultaneous measurement of strain and temperature. The envelope can provide strain and temperature sensitivities of 58.0 pm/με and 1.05 nm/°C. The finesse fringe provides sensitivities of 5.9 pm/με and 1.36 nm/°C.
060.2370 Fiber optics sensors 060.2420 Fibers, polarization-maintaining 120.3180 Interferometry Chinese Optics Letters
2019, 17(8): 080601
Author Affiliations
Abstract
1 School of Optical and Electronic Information, National Engineering Laboratory for Next Generation Internet Access System, Huazhong University of Science and Technology, Wuhan 430074, China
2 Department of Electronics and Information Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
3 Enviromental Protection Science and Technology Co., Ltd., Wuhan 430070, China
In this Letter, an alternative solution is proposed and demonstrated for simultaneous measurement of axial strain and temperature. This sensor consists of two twisted points on a commercial single mode fiber introduced by flame-heated and rotation treatment. The fabrication process modifies the geometrical configuration and refractive index of the fiber. Different cladding modes are excited at the first twisted point, and part of them are coupled back to the fiber core at the second twisted point. Experimental results show distinct sensitivities of 34.9 pm/με with 49.23 pm/°C and 36.19 pm/με with 62.99 pm/°C for the two selected destructive interference wavelengths.
060.2370 Fiber optics sensors 060.2430 Fibers, single-mode Chinese Optics Letters
2018, 16(4): 040602
华中科技大学,光电子工程系,湖北,武汉,430074
提出了一种新颖偏振不敏感的阵列波导光栅(AWG).器件的输入端增加了一个全光学偏振自动控制器(AOPSC),可将注入AWG的随机偏振的输入光转换为与AWG中TE0模偏振方向相同且功率损耗很小的线偏振光.AWG结构设计采用非对称的平面波导,包层与波导芯层的相对折射率差为0.7%,波导芯层的宽厚比要高,可以消除TE与TM模的简并,使波导中只能激励TE0模,而使TM0模截止.这种AWG结构完全消除了不同偏振态信号光对AWG工作性能的影响,从而使器件对偏振不敏感.设计的8×0.8nm器件整体尺寸为2cm×1cm,串扰优??30dB,最大插入损耗为4.2dB.
阵列波导光栅 波分复用 偏振不敏感 全光学偏振自动控制器
