Phase shifted and cascaded long-period fiber gratings

Liu, Y; Williams, J.A.R.; Zhang, L; Bennion, I.

doi:10.1016/s0030-4018(99)00191-1

Cited by 69 publications

(38 citation statements)

References 8 publications

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“…In this case, the main resonant peak appears at a shorter wavelength while the intensity of the secondary resonant band at a longer wavelength decreases. This spectrum transition behavior is similar to that of the conventional phase-shifted LPG [8,9]. The simulation also shows that the partially etched phaseshifted LPG covers a wide wavelength range of 30 nm.…”

Section: Reconfigurable Phase-shifted Long-period Gratingsupporting

confidence: 70%

Design of a phase-shifted long-period grating using the partial-etching technique

Chung

Yin

2005

Microw. Opt. Technol. Lett.

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cascade Microtech probe station using ACP-40 CPW probes by Cascade and 40 Å GSG Picoprobes by GGB Industries. An Agilent 8510C network analyzer is used for the S-parameter measurements between 500 MHz and 4 GHz.The capacitance C and quality factor Q are computed using the complex input impedance (Z ϭ r Ϫ jX C ϭ r Ϫ j/C), C ϭ 1/X C , and Q ϭ X C /r. The Q is used to characterize the losses in the lumped circuit. Q can be defined as the ratio of stored energy to the average energy dissipated in the system per cycle. For any type of passive circuits represented by admittance or impedance, this relation can be defined accordingly. Therefore, Figure 5 shows the capacitance values of measurement data for the BST IDC as a function of frequency for various applied voltages.As shown in Figure 5, as the frequency increases, the capacitance decreases, which is proportional to exponential function of frequency. The capacitance values for undoped BST IDC and 3% Mn-doped BST IDC are found to be about 5-1.6 pF and 4.5-1.4 pF, respectively, at the bias voltage of 0 V. Additionally, at the bias voltage of 20 V, the capacitance values are obtained by about 3.6 -1.3 pF and 3.1-1.0 pF for each BST interdigital capacitor, respectively.The measured Q and C as a function of the frequency at 3.5 GHz and applied DC voltage is shown in Figure 6. From the figure, the values of Q vary from about 9.25 (0 V) to 11.1 (20 V) for the undoped BST IDC and from about 10.71 (0 V) to 11.44 (20 V) for the Mn-doped BST IDC. Also, C varies from about 1.608 pF (0 V) to 1.422 pF (20 V) for the undoped BST IDC and from about 1.422 pF (0 V) to 1.032 pF (20 V) for the Mn-doped BST IDC. Tunability is 11.6%, and 27.4%, respectively. CONCLUSIONA BST tunable capacitor within an interdigital structure with high tunability and low-loss tangent has been successfully demonstrated. The 3% Mn-doped BST interdigital capacitor exhibits a 27.4% better tuning performance at 3.5 GHz and a 20% better loss-tangent characteristic, as compared with the undoped BST thin-film capacitor. This BST IDC can be used in microwave tunable devices.

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Section: Reconfigurable Phase-shifted Long-period Gratingsupporting

confidence: 70%

Design of a phase-shifted long-period grating using the partial-etching technique

Chung

Yin

2005

Microw. Opt. Technol. Lett.

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“…Afterwards, the same structure was also applied to LPFGs [30,36]. This kind of grating found applications not only in telecommunications, as wavelength demultiplexing and optical filters, but also in sensing for the measurement of temperature and refractive index [37].…”

Section: Phase-shifted Lpfgsmentioning

confidence: 99%

Manufacturing and Spectral Features of Different Types of Long Period Fiber Gratings: Phase-Shifted, Turn-Around Point, Internally Tilted, and Pseudo-Random

Chiavaioli

Baldini

Trono

2017

Fibers

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Abstract:The manufacturing and spectral features of different types of long period fiber gratings (LPFGs), ranging from phase-shifted, turn-around point, and internally tilted gratings, to pseudo-random gratings, are described and discussed in detail. LPFGs were manufactured on boron-germanium co-doped photosensitive optical fibers with the point-by-point technique using an excimer KrF laser operating at 248 nm. The developed experimental setup to manufacture high-quality LPFGs was designed to totally customize any type of gratings with the possibility of setting different parameters, such as the grating period (or pitch), the number of grating planes, the number of laser shots for each plane, etc. Some important spectral features of the LPFGs' spectra were taken into account. This allows realizing homemade devices useful in several fiber-based applications, such as optical filtering, coupling systems, random lasers, physical and chemical sensing, and biosensing.

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“…The wavelength spacings between adjacent transmission dips are 14.3, 15.2 16.1 nm at around the individual resonant wavelengths, respectively. The transmission of the MZI can be described by [16] 2 1 1 0…”

Section: Fabrication and Working Principlementioning

confidence: 99%

Microfiber Mach-Zehnder interferometer based on long period grating for sensing applications

Tan¹,

Sun²,

Jin³

et al. 2013

Opt. Express

105

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A Mach-Zehnder interferometer (MZI) composed by a pair of long period gratings (LPGs) fabricated in silica microfiber for sensing applications is demonstrated. Each LPG is fabricated with a pulsed CO2 laser by creating six periodical deformations along fiber length with only one scanning cycle. The length of the MZI can reach as short as 8.84 mm when the diameter of the microfiber is 9.5 μm. Compared with the ones fabricated in single-mode fibers, the present MZI is much shorter owing to the large effective-index difference between the fundamental and higher order modes. The microfiber MZI exhibits a sensitivity to surrounding refractive index (RI) of 2225 nm per refractive index unit and the temperature sensitivity of only 11.7 pm/°C. Theoretical analysis suggests that the performances of the MZI sensor can be improved by using thinner microfibers with a diameter down to 3.5 μm: The sensitivity can be greatly enhanced due to the stronger evanescent-field interaction and reduced dispersion factor; the transmission dips become narrower which benefits high-resolution measurement; the thinner fiber also allows further reduction in device length. The present device has great potential in biochemical and medical sensing due to the advantages including easy fabrication, excellent compactness and high sensitivity.

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Phase shifted and cascaded long-period fiber gratings

Cited by 69 publications

References 8 publications

Design of a phase-shifted long-period grating using the partial-etching technique

Design of a phase-shifted long-period grating using the partial-etching technique

Manufacturing and Spectral Features of Different Types of Long Period Fiber Gratings: Phase-Shifted, Turn-Around Point, Internally Tilted, and Pseudo-Random

Microfiber Mach-Zehnder interferometer based on long period grating for sensing applications

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