scholarly journals Fiber Twist-based Wavelength Tunability in Tapered Optical Fiber Filters

2020 ◽  
Vol 28 (4) ◽  
Author(s):  
Maisarah Mansor ◽  
Afiqah Mohd Nawi ◽  
Nadiah Husseini Zainol Abidin ◽  
Muhammad Firdaus Omar ◽  
Mohd Adzir Mahdi ◽  
...  

This work demonstrates the tunability of tapered single mode fiber (SMF) and tapered polarization maintaining fiber (PMF) filters based on fiber twisting method. One end of the tapered fiber was twisted from 0o until 100o using the Vytran Fiber Processing System. Observation on the spectral output shows that the fiber twisting technique is a viable option to impart tunability in tapered fibers with total shift of 15 and 10 nm, respectively for SMF and PMF. Better tunability is observed in the SMF filter due to its simple physical structure and more straightforward interferometry effect but a significantly higher extinction ratio is observed for the PMF filter. Both filters exhibited region of linear wavelength shift with corresponding R2 values of 0.9924 and 0.9294 for SMF and PMF. The simplicity and reliability of the filter may pave the way for the development of a practical and compact tunable all-fiber filter for laser systems.

2016 ◽  
Vol 14 (5) ◽  
pp. 050604-50608
Author(s):  
Zaihang Yang Zaihang Yang ◽  
Hao Sun Hao Sun ◽  
Tingting Gang Tingting Gang ◽  
Nan Liu Nan Liu ◽  
Jiacheng Li Jiacheng Li ◽  
...  

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5440 ◽  
Author(s):  
Xiaopeng Han ◽  
Chunyu Liu ◽  
Shengxu Jiang ◽  
Shuo Leng ◽  
Jiuru Yang

A novel in-fiber Mach-Zehnder interferometer based on cascaded up-down-taper (UDT) structure is proposed by sandwiching a piece of polarization maintaining fiber between two single-mode fibers (SMF) and by utilizing over-fusion splicing method. The dual up tapers respectively act as fiber splitter/combiner, the down taper acts as an optical attenuator. The structure parameters are analyzed and optimized. A larger interference fringe extinction ratio ~15 dB is obtained to achieve refractive index (RI) sensing based on intensity demodulation. The experimental results show that the RI sensitivity is −310.40 dB/RIU with the linearity is improved to 0.99 in the range of 1.3164–1.3444. The corresponding resolution can reach 3.22 × 10−5 RIU, which is 6.8 times higher than wavelength demodulation. The cross sensitivity which caused by temperature fluctuation is less than 1.4 × 10−4.


Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 258
Author(s):  
Weihao Yuan ◽  
Changyuan Yu

We report the ring core fiber spliced with single mode fiber and no core fiber which is used for temperature and refractive index (RI) sensing. The Mach-Zehnder interferometer (MZI) is formed with this kind of sandwich fiber structure and the maximum extinction ratio of the interference spectra reaches 27 dB with the free spectra range of 12 nm. The MZI fiber sensor is applied for temperature sensing with the sensitivity of 69 pm/°C and 0.051 dB/°C. The RI sensitivity reaches 182.07 dB/RIU and −31.44 nm/RIU with the RI ranging from 1.33 to 1.38. The RI value can be directly demodulated with the interference dip intensity which shows insensitivity to temperature. The demodulation of temperature can be achieved by using the linear equations between dip wavelength shift with the variation of temperature and RI.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Josu Amorebieta ◽  
Angel Ortega-Gomez ◽  
Gaizka Durana ◽  
Rubén Fernández ◽  
Enrique Antonio-Lopez ◽  
...  

AbstractWe propose and demonstrate a compact and simple vector bending sensor capable of distinguishing any direction and amplitude with high accuracy. The sensor consists of a short segment of asymmetric multicore fiber (MCF) fusion spliced to a standard single mode fiber. The reflection spectrum of such a structure shifts and shrinks in specific manners depending on the direction in which the MCF is bent. By monitoring simultaneously wavelength shift and light power variations, the amplitude and bend direction of the MCF can be unmistakably measured in any orientation, from 0° to 360°. The bending sensor proposed here is highly sensitive even for small bending angles (below 1°).


2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Marta Nespereira ◽  
João M. P. Coelho ◽  
José Manuel Rebordão

The response of ultrashort-length CO2-induced long-period fiber grating (LPFG) sensors to torsion is reported. While engraving using CO2 laser radiation, the fiber is submitted to high tension allowing the obtainment of gratings with shorter lengths, down to 2.4 mm, which is almost one order of magnitude lower than the usual. Also, the fiber is only irradiated in one side, creating an asymmetrical profile leading to highly birefringent gratings. Sensitivity to axial twists is demonstrated, with values up to 0.15 nm/(rad/m) for the resonant wavelength shift and higher than 0.03 dBm/(rad/m) for the variation in the intensity (attenuation). Discrimination between rotation directions, clockwise and counterclockwise, was observed.


2012 ◽  
Vol 30 (3) ◽  
pp. 362-367 ◽  
Author(s):  
Mohammad Karimi ◽  
F. Surre ◽  
Tong Sun ◽  
K. T. V. Grattan ◽  
W. Margulis ◽  
...  

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Tao Zhu ◽  
Leilei Shi ◽  
Min Liu ◽  
Wei Huang

A review of long-period fiber gratings (LPFGs) with special structures induced by scanning CO2laser pulses in single mode fiber (SMF) is presented in this paper. In the first part, the special structures and fabrication methods of LPFGs are demonstrated in detail. Next, the special LPFG-based sensors are demonstrated, such as refractive index sensor, strain sensor with temperature compensation, and torsion sensor without temperature crosstalking. Finally, several investigation methods including intensity, wavelength shift, and fiber ring laser demodulation are discussed.


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