Abstract
A cascaded symmetrical dual-taper Mach-Zehnder interferometer structure based on guided-mode and leaky-mode interference is proposed in this paper. Firstly, the interference spectrum characteristics of interferometer has been analyzed by the Finite Difference-Beam Propagation Method (FD-BPM). When the diameter of taper waist is 20 μm–30 μm, dual-taper length is 1 mm and taper distance is 4 cm–6 cm, the spectral contrast is higher, which is suitable for sensing. Secondly, experimental research on refractive index sensitivity is carried out. A refractive index sensitivity of 62.78 nm/RIU (refractive index unit) can achieved in the RI range of 1.3333–1.3792 (0%~25% NaCl solution), when the sensor structure parameters meet the following conditions: diameter of taper waist is 24 μm, dual-taper length is 837 μm and taper distance is 5.5 cm. The spectrum contrast is 0.8 and measurement resolution is 1.6 × 10−5 RIU. The simulation analysis is highly consistent with experimental results. Research shows that the sensor has promising application in low RI fields where high-precision measurement is required due to its high sensitivity and stability.
Highlights
The refractive index (RI) is a significant physical parameter to reflect the characteristics of material [1,2]
There have been many reports on optical fiber sensors which were used for measuring liquid RI, but the sensitivities of these sensors are not high enough in low RI liquid or the structures are complex [5]
Tian put forward a new type fiber RI sensors based on two positive-cascaded 3 dB tapers Mach-Zehnder interferometer by optical fiber fusion splicer [6]
Summary
The refractive index (RI) is a significant physical parameter to reflect the characteristics of material [1,2]. The principle is that the middle structure can enhance the evanescent enhance the evanescent field of optical energy and increase the exposed energy of the light field for field of optical energy and increase the exposed energy of the light field for achieving the improvement achieving the improvement of RI sensing sensitivity, and a RI sensitivity of 28.6 nm/RIU has been of RI sensing sensitivity, and a RI sensitivity of 28.6 nm/RIU has been realized in the RI range of realized in the RI range of 1.3320–1.3890 These sensors show high sensitivities in the high RI measurements field (near the RI of these sensors show high sensitivities in the high RI measurements field (near the RI silica), it can hardly meet the high-precision measurement requirement in low RI measurement field. Used in the field of stress [9,10], temperature [11], and so on
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
