Author Affiliations
Abstract
State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
A high sensitive refractive index sensor based on the cladding etched photonic crystal fiber (PCF) Mach-Zehnder interferometer (MZI) is proposed, which is spliced a section of photonic crystal fiber between two single modes fibers (SMFs).The interference fringe of the MZI shifts with the variation of the ambient refractive index (RI). It is found that the RI sensitivity slightly decrease with an increase in the interference length. The sensitivities of MZI with 35mm PCF, 40mm PCF, and 45mm PCF are 106.19nm/RIU, 93.33nm/RIU, and 73.64nm/RIU, respectively, in the range of 1.333 to 1.381. After etched, the RI sensitivity of the MZI could be improved obviously. The RI sensitivities of the MZI with 35mm PCF are up to 211.53nm/RIU and 359.37nm/RIU when the cladding diameter decreases to 112μm and 91μm, respectively. Moreover, the sensor is insensitive to temperature, and the measured sensitivity is only 9.21pm/℃ with the range from 20℃ to 500℃. In addition, the sensor has advantage of simple fabrication, low cost, and high RI sensitivity.
Refractive index sensor Mach-Zehnder interferometer photonic crystal fiber hydrofluoric acid Photonic Sensors
2019, 9(2): 02126
Author Affiliations
Abstract
State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
In order to improve the morphology of microchannels fabricated by femtosecond laser ablation, the thermal process was introduced into the post-treatment processing. It was found that the thermal process cannot only decrease the roughness but also the width and depth of the microchannel. The change rates of width, depth, and roughness of the microchannel increase with processing temperature. When we prolong the time of constant temperature, the change rate of the width decreases at the beginning, and then it tends to be stable. However, the change rates of depth and roughness increase, and then they tend to be stable. In this Letter, we discuss the reasons of the above phenomena.
140.3390 Laser materials processing 230.7380 Waveguides, channeled Chinese Optics Letters
2018, 16(10): 101402
