Tunable Optical Filter Based on Mechanically Induced Cascaded Long Period Optical Fiber Grating

We have proposed and demonstrated experimentally a novel and simple tunable optical filter based on mechanically induced and cascaded long period optical fiber gratings. In this filter variable FWHM and center wavelength is provided by cascading long period and ultralong period optical fiber gratings with different periods in a novel fiber structure. We report here for the first time to our knowledge the characterization of mechanically induced long period fiber gratings with periods up to several millimeters in novel multimode-single-mode-multimode fiber structure. We have obtained maximum loss peak of around 20 dB.

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Helically twisted long-period fiber gratings of YOFC single-mode fiber with optical fiber welding machine

Optica Applicata ◽

10.37190/oa210308 ◽

2021 ◽

Vol 51 (3) ◽

Author(s):

Yunfeng Bai ◽

Zelong He ◽

Jiyuan Bai ◽

Suihu Dang

Keyword(s):

Single Mode ◽

Resonance Wavelength ◽

Single Mode Fiber ◽

Resonant Peak ◽

Fiber Grating ◽

Fiber Gratings ◽

Long Period ◽

Welding Machine ◽

Long Period Fiber Gratings ◽

Period Fiber Grating

The single-mode fiber provided by YOFC inc is employed for spiral processing by commercial welding machine. It can clearly see the periods structure under the light, but there is no obvious deformation of the fiber core, cladding and surface morphology under a microscope. There is an obvious resonant peak near 1560 nm, half peak width is about 25 nm, the depth of the resonant peak closed to –26 dB, when the period is about 411 μm. It agrees with theoretical calculation results according to the long-period fiber grating coupled-mode theory. The resonance wavelength is caused by coupling between the fundamental mode and the LP14 mode. The responsivities of the helically twisted long-period fiber gratings (H-LPFG) for the temperature is measured, the resonance wavelength is linear with temperature, the slope is 86 pm/℃. Because it is easy to inscribe by commercial welding machine, and has a strong resonance peak, it has potential applications as the temperature sensor.

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Ultrashort Long-Period Fiber Grating Sensors Inscribed on a Single Mode Fiber Using CO2 Laser Radiation

Journal of Sensors ◽

10.1155/2017/4196431 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Marta Nespereira ◽

João M. P. Coelho ◽

Manuel Abreu ◽

José Manuel Rebordão

Keyword(s):

Laser Radiation ◽

Single Mode ◽

Single Mode Fiber ◽

Fiber Grating ◽

Fiber Gratings ◽

Long Period Fiber Grating ◽

Long Period ◽

Long Period Fiber Gratings ◽

Co2 Laser Radiation ◽

Period Fiber Grating

Sensing performances of ultrashort (as low as 2.4 mm) long-period fiber gratings fabricated with CO2 laser radiation using commercial single mode fibers are presented. These lengths are, to our knowledge, the shortest of those found in the literature for this kind of sensors, approaching those typical in fiber Bragg gratings. Sensitivity to temperature and refractive index are demonstrated, with performances within the range expected for a single LPFG written on a single mode fiber without any enhancing technique. Analysis on results is made based on both theoretical and experimental data.

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Mechanically induced long period fiber gratings on single mode tapered optical fiber for structure sensing applications

10.1117/12.2187339 ◽

2015 ◽

Author(s):

María G. Pulido-Navarro ◽

Sigifredo Marrujo-García ◽

José A. Álvarez-Chávez ◽

Jesús S. Velázquez-González ◽

Fernando Martínez-Piñón ◽

...

Keyword(s):

Optical Fiber ◽

Single Mode ◽

Fiber Gratings ◽

Long Period ◽

Sensing Applications ◽

Long Period Fiber Gratings ◽

Tapered Optical Fiber

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Immunosensor Based on Long-Period Fiber Gratings for Detection of Viruses Causing Gastroenteritis

Sensors ◽

10.3390/s20030813 ◽

2020 ◽

Vol 20 (3) ◽

pp. 813 ◽

Cited By ~ 2

Author(s):

Marta Janczuk-Richter ◽

Beata Gromadzka ◽

Łukasz Richter ◽

Mirosława Panasiuk ◽

Karolina Zimmer ◽

...

Keyword(s):

Optical Fiber ◽

Medical Diagnostics ◽

Label Free ◽

Fiber Gratings ◽

Fast Detection ◽

Long Period ◽

Highly Sensitive ◽

Protein Receptors ◽

Long Period Fiber Gratings ◽

Vaccine Testing

Since the norovirus is the main cause of acute gastroenteritis all over the world, its fast detection is crucial in medical diagnostics. In this work, a rapid, sensitive, and selective optical fiber biosensor for the detection of norovirus virus-like particles (VLPs) is reported. The sensor is based on highly sensitive long-period fiber gratings (LPFGs) coated with antibodies against the main coat protein of the norovirus. Several modification methods were verified to obtain reliable immobilization of protein receptors on the LPFG surface. We were able to detect 1 ng/mL norovirus VLPs in a 40-min assay in a label-free manner. Thanks to the application of an optical fiber as the sensor, there is a possibility to increase the user’s safety by separating the measurement point from the signal processing setup. Moreover, our sensor is small and light, and the proposed assay is straightforward. The designed LPFG-based biosensor could be applied in both fast norovirus detection and in vaccine testing.

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Ultrashort Long-Period Fiber Gratings Inscribed on a Single-Mode Fiber for Torsion Sensing Applications

Journal of Sensors ◽

10.1155/2018/4131790 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Marta Nespereira ◽

João M. P. Coelho ◽

José Manuel Rebordão

Keyword(s):

Single Mode ◽

Single Mode Fiber ◽

Wavelength Shift ◽

Fiber Grating ◽

Long Period ◽

Sensing Applications ◽

High Tension ◽

Long Period Fiber Gratings ◽

Order Of Magnitude ◽

Period Fiber Grating

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.

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