Long period grating has a wide variety of applications, including band-rejection filters, gain flattening filter and sensors. Various gratings with complex structures have been designed: gratings combining several LPFGs, LPFGs with superstructures, chirped gratings, and gratings. In essence, a long period fibre grating (LPFG) is an all-fibre device with wavelength dependent loss. As a band rejection filter, all light in a spectral slice is discarded without affecting the amplitude and phase of neighbouring wavelengths, with the additional advantage of low insertion losses. Microbend gratings, which are antisymmetric with respect to the fiber axis, create a resonance between the core mode and...
Traditionally, long period fiber gratings (LPG) are made in passive optical fibers that have negligible loss. However, loss or gain that can be controlled via optical pumping adds a new degree of freedom and
Fiber Bragg gratings are reflective structures in the core of an optical fiber with a periodic or aperiodic perturbation of the effective refractive index.
3. Long period gratings in D-shaped fibers short-period FBGs is their intrinsic SRI sensitivity. Nevertheless, the fiber section geometry strongly influences the sensitivity characteristics of the
This paper presents a review of the evolution of LPFGs, with a specific focus on the progression and current trends of mechanically induced
Abstract and Figures An apodized Long Period Grating (LPG) is presented to compute and depict the temperature sensitivity for different resonant wavelengths in the transmission spectrum.
We have demonstrated the feasibility of achieving high-performance fiber polarizers (insertion loss <0.5 dB, extinction ratio >30 dB), based on
In this work, we report about our recent results concerning the fabrication of Long Period Grating (LPG) sensors in several optical fibers, through the Electric Arc Discharge (EAD) technique.
Except the common advantaged of fiber-optic sensor, LPFGs have higher sensitivity, smaller size, and narrower bandwidth, which has attracted research interests for several decades.
Optic fiber sensors for refractive index (RI) measurement have brought about widespread attention in an extensive range owing to their unique properties. In this paper, we theoretically
In this chapter we will make a review of the relevant aspects of LPFGs.
We report an analysis of the transmission characteristics of long period gratings written in a linearly tapered optical fiber. Such gratings are best analyzed by a coupled mode theory that includes
Experimental investigation of the cladding modes excited by long-period gratings, as well as sensitivity of the long-period grating spectrum to
Long-period fiber gratings (LPFGs) functioning as band-reject filters have played a pivotal role in the realm of optical communication. Since their
As an important passive optical component, long-period fiber gratings (LPFGs) have all the advantages of optical fiber sensors, such as anti-electromagnetic interference, corrosion resistance, high
In this paper, the fabrication and characterization of long period gratings inscribed with a femtosecond laser system was studied, theoretically and experimentally.
We report here for the first time the fabrication and characterisation of long-period fibre gratings (LPFGs) with period size up to several millimetres. The resonant loss peaks of these ultra
We present a detailed investigation into the sensitivity of long-period fiber gratings (LPFGs) as a function of temperature, strain, and surrounding refractive index, with particular attention to the higher order
We demonstrate the fabrication of the long-period fiber gratings (LPFGs) in the thinned cladding fiber by CO2 laser and the characteristics of the
Present work deals with theoretical analysis of dispersion characteristics of long period fiber grating using straight forward coupled mode theory. Simple analytical solutions are obtained for
In this work, for the first time, we demonstrate long period gratings (LPG) in nanostructured optical fibers and their response to gamma radiation. Nanostructured fibers show distinctive features
2. Fabrication methods of long-period fibre gratings The inscription of long-period gratings on optical fibre basically consists in the generation of a periodical perturbation of the refractive index in the
A novel concept of individually switchable and widely tunable erbium-doped multiwavelength fiber laser (MWFL) is proposed and experimentally demonstrated. The key
Abstract In this paper, the fabrication of arched fiber core based on single-mode fiber is first proposed and experimentally studied about the relevant sensing characteristics. A novel kind of
In this paper, comprehensive remarks are given that focus on the main fabrications and wide applications of helical long-period fiber gratings
Download Citation | On May 1, 2026, Weibin Wu and others published In-situ and direct wear measurement of full-size water-lubricated journal bearings by embedded chirped fibre Bragg gratings
Specifically, long period gratings (LPG) have been mechanically induced in different optical fibers through a 3D printed nearly sinusoidal grooved structure. LPGs have been mechanically induced in
Long-period fiber grating A long-period fiber grating couples light from a guided mode into forward propagating cladding modes where it is lost due to absorption and scattering. The coupling from the
Advantages of long-period grating (LPG) based optical fibers for sensing applications along with different fabrication techniques to draw grating on the core of fiber have been reviewed. Some advantages
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