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Proceedings ArticleDOI

Modeling of fiber Bragg gratings written in tapered optical fibers

25 Oct 2013-Vol. 8903, pp 229-235
TL;DR: In this paper, the numerical results of Bragg gratings modeling are shown, based on coupled mode theory and transfer matrix method, which gives highly accurate results for reflection width evaluation.
Abstract: In this paper the numerical results of tapered fiber Bragg gratings modeling are shown. Presented model, based on coupled mode theory and transfer matrix method for tapered fiber Bragg gratings, gives highly accurate results for reflection width evaluation. Few simulations were made for three different configurations of tapered fiber Bragg structures, as well as comparison between theoretical and experimental results.
Citations
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Journal ArticleDOI
TL;DR: A novel concept of a Fabry-Perot (F-P) cavity composed of two linearly chirped fiber Bragg gratings written in a thermally fused fiber taper is presented, which is based on strain-induced detuning of the F-P resonator.
Abstract: A novel concept of a Fabry–Perot (F–P) cavity composed of two linearly chirped fiber Bragg gratings written in a thermally fused fiber taper is presented. Both chirped gratings are written in counter-directional chirp configuration, where chirps resulting from the optical fiber taper profile and linearly increasing grating periods cancel each other out, forming a high-quality F–P resonator. A new strain-sensing mechanism is proposed in the presented structure, which is based on strain-induced detuning of the F–P resonator. Due to the different strain and temperature responses of the cavity, the resonator can be used for the simultaneous measurement of these physical quantities, or it can be used as a temperature-independent strain sensor.

35 citations

Journal ArticleDOI
TL;DR: In this paper, spectrally tailored tapered chirped fiber Bragg gratings (TCFBGs) are considered for use as strain sensors, and the results show that TCFBGs exhibit monotonic strain response over the wide operating range of the applied force.
Abstract: In this paper, spectrally tailored tapered chirped fiber Bragg gratings (TCFBGs) are considered for use as strain sensors. Both gratings were written in fused tapered optical fiber using linearly chirped fiber Bragg gratings in co-directional and counter-directional chirp configurations. Theoretical and numerical analysis as well as experimental verification of the influence of applied strain on spectral width of both TCFBG structures were carried out. The results show that TCFBGs exhibit monotonic strain response over the wide operating range of the applied force. Compared with standard tapered FBG written using uniform phase mask, in the case of co-directionally written TCFBG with substantially larger grating chirp the monotonic operating range can be easily broadened toward the higher strain values (even above the applied force at which the optical fiber breaks). In turn, the intrinsic chirp of the counter-directionally written TCFBG can be tailored in such a way as to ensure that the monotonicity of its strain response is always satisfied when tensile force is applied. This is due to the spectral broadening of the reflected spectrum when strain increases.

30 citations


Cites background from "Modeling of fiber Bragg gratings wr..."

  • ...For such parameters, it may be assumed that the linear reduction of the taper diameter provides an approximately linear decrease of the neff [14]....

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Journal ArticleDOI
TL;DR: A versatile numerical model for spectral transmission/reflection, group delay characteristic analysis, and design of tapered fiber Bragg gratings (TFBGs) is presented, creating a universal tool for TFBG analysis and design.
Abstract: A versatile numerical model for spectral transmission/reflection, group delay characteristic analysis, and design of tapered fiber Bragg gratings (TFBGs) is presented. This approach ensures flexibility with defining both distribution of refractive index change of the gratings (including apodization) and shape of the taper profile. Additionally, sensing and tunable dispersion properties of the TFBGs were fully examined, considering strain-induced effects. The presented numerical approach, together with Pareto optimization, were also used to design the best tanh apodization profiles of the TFBG in terms of maximizing its spectral width with simultaneous minimization of the group delay oscillations. Experimental verification of the model confirms its correctness. The combination of model versatility and possibility to define the other objective functions of Pareto optimization creates a universal tool for TFBG analysis and design.

26 citations


Cites methods from "Modeling of fiber Bragg gratings wr..."

  • ...The ratio of optical power which propagates in the fiber core Pcore to the total optical power of the fundamental LP01 mode P is calculated using the formula [31]...

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Journal ArticleDOI
TL;DR: In this article, a method of spectral width tailoring of tapered fiber Bragg gratings is theoretically analyzed and experimentally verified, based on inscription grating structures in which synthesis of chirps comes from both taper profile and a linearly chirped phase mask used for grating inscription.

23 citations

Journal ArticleDOI
TL;DR: In this article, the development of advanced set-ups employing the phase mask inscription scheme is discussed and supported with the descriptions of structures designed and fabricated with the use of the laboratory stages constructed at the IES.
Abstract: In this paper research on the development of the fiber Bragg grating (FBG) technology which has been conducted at the Institute of Electronic Systems (IES), Warsaw University of Technology (WUT) since 2004 is presented. In particular the directions in the development of advanced set-ups employing the phase mask inscription scheme are discussed and supported with the descriptions of structures designed and fabricated with the use of the laboratory stages constructed at the IES. The novelty of the presented solutions is based on the combination of numerous techniques of the external modification of the interferometric patterns (projected onto cores of photosensitive fibers to modulate their refractive index) as well as application of the modification of the internal properties of the waveguides themselves by the means of introducing strain or tapering. The development of these sophisticated set-ups resulted in the inscription of FBGs with precisely designed spectral characteristics which found application in telecommunications and sensor technology are also illustrated here. The paper is summarized with the specification of the most important achievements attained at the lab and drafting of the possible directions of further research.

19 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the spectral properties of fiber reflection and transmission gratings are described and examples are given to illustrate the wide variety of optical properties that are possible in fiber gratings.
Abstract: In this paper, we describe the spectral characteristics that can be achieved in fiber reflection (Bragg) and transmission gratings. Both principles for understanding and tools for designing fiber gratings are emphasized. Examples are given to illustrate the wide variety of optical properties that are possible in fiber gratings. The types of gratings considered include uniform, apodized, chirped, discrete phase-shifted, and superstructure gratings; short-period and long-period gratings; symmetric and tilted gratings; and cladding-mode and radiation-mode coupling gratings.

3,330 citations


"Modeling of fiber Bragg gratings wr..." refers background or methods in this paper

  • ...An uniform FBG can be described by only one matrix given by [1]:...

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  • ...In order to evaluate transmission and reflection of the TFBG using modified transfer matrix method it is necessary to divide tapered structure into many uniform pieces (subsections), what is also called piecewise-uniform approach [1] (Fig....

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  • ...Thus, in order to simulate propagation of electromagnetic wave through the fiber Bragg grating written in tapered region it is necessary to modify transfer matrix method shown in [1]....

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  • ...1 Coupled mode theory and transfer matrix method Assuming the ideal mode-approximation, transverse component of the electric field is a superposition of ideal modes in waveguide with no perturbation [1]:       j t j T j z j j z j j e y x e e z B e z A t z y x T j j E ) ( ) ( ) ( ) , ( ] ) ( ) ( [ ) , , , (    (1)...

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  • ...Note that each subsection has to fulfill condition Δl>>Λ, which mean that the length of each subsection should be much longer than grating period [1]....

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Journal ArticleDOI
TL;DR: In this article, the problem of propagation and interaction of optical radiation in dielectric waveguides is cast in the coupled-mode formalism, which is useful for treating problems involving energy exchange between modes.
Abstract: The problem of propagation and interaction of optical radiation in dielectric waveguides is cast in the coupled-mode formalism. This approach is useful for treating problems involving energy exchange between modes. A derivation of the general theory is followed by application to the specific cases of electrooptic modulation, photoelastic and magnetooptic modulation, and optical filtering. Also treated are nonlinear optical applications such as second-harmonic generation in thin films and phase matching.

1,952 citations


"Modeling of fiber Bragg gratings wr..." refers methods in this paper

  • ...THEORETICAL BACKGROUND One of the most popular method for describing interaction between electromagnetic wave and periodic structure is coupled mode theory [3]....

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Book
01 Jan 2000

1,493 citations


"Modeling of fiber Bragg gratings wr..." refers background in this paper

  • ...Where ξw for fundamental mode can be written as [7]:...

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  • ...The relative amount of optical power which propagates in fiber core for a give optical fiber parameters can be calculated using the following formula [7]:...

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01 Jan 2012
TL;DR: In this article, the authors presented the modeling and simulation of an optical fiber Bragg grating for maximum reflectivity, minimum side lobe, which was based on solving coupled mode equations by transfer matrix method.
Abstract: This paper presents the modeling and simulation of an optical fiber Bragg grating for maximum reflectivity, minimum side lobe. Gating length represents as one of the critical parameters in contributing to a high performance fiber Bragg grating. The reflection spectra and side lobes strength were analyzed with different lengths .The side lobes have been suppressed using raised cosine apodization while maintaining the peak reflectivity. Such simulations are based on solving coupled mode equations by transfer matrix method.

44 citations


Additional excerpts

  • ...When perturbation takes place the amplitudes Aj(z) and Bj(z) of jth mode in +z and –z directions can be written as [4]: ) ( ] [ ) ( ) ( z K e B e A j dz dA T kj z j k k z j k j k j k j           (3)...

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Journal ArticleDOI
TL;DR: In this article, a combination of abrupt tapers and fiber Bragg gratings was used to study the properties of a Fabry-Perot cavity and a phase-shifted Bragg grating where the phase shift is associated to the tapered fiber region.
Abstract: Fiber structures based on the combination of abrupt tapers and fiber Bragg gratings are studied. Two situations are explored—in one, the taper is fabricated in the fiber region with a fiber Bragg grating; in the other, the taper is first fabricated followed by the fiber Bragg grating. It is shown that the first device presents the properties of a Fabry-Perot cavity and the other of a phase-shifted Bragg grating, where the phase shift is associated to the tapered fiber region. The sensing characteristics of these structures are studied, and it is shown that the temperature sensitivities are similar but with observable different responses to strain.

24 citations