Properties of Length-Apodized Phase-Shifted LPGs Operating at the Phase Matching Turning Point

Abstract

The characteristics of length-apodized phaseshifted fibre optic long period gratings with full and partial nanostructured coatings have been explored theoretically and experimentally. The twin rejection bands that are characteristic of the length-apodized phase-shifted long period gratings are studied for a long period grating (LPG) operating at the phase matching turning point. When one half of the length of the LPG is coated, complex bandgap like structure appears within the transmission spectrum, which may be of benefit to spectral filter design.Index Terms-optical fiber long period gratings, nanoscale coatings, optical filter.

Real time monitoring of biofilm formation on coated medical devices for the reduction and interception of bacterial infections

“…The LPG sensor is also sensitive to temperature and strain on the fibre, which could be compensated using a reference LPG. [34][35][36][37] In the clinic, the instrumented ETT ( Fig. 4) would provide a constant readout of wavelength shift, which can then be used to estimate the biomass of any biofilm on the surface of the device.…”

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

“…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].…”

“…LPFGs were manufactured on photosensitive optical fibers with the point-by-point technique using an excimer KrF laser. Without any purpose to show the application of the realized gratings and in addition to the previous literature on the field [30,31], the attention of this paper will be completely focused on how all the above- Here, the manufacturing and spectral features of different type of LPFGs, ranging from standard (see Figure 1), phase-shifted (see Figure 2a) and internally tilted (see Figure 2b) gratings up to pseudo-random gratings (see Figure 2c), are described and discussed in detail. An in-house procedure, as well as an ad-hoc developed setup allow the high-quality manufacturing of any type of LPFGs with a total customization by setting different parameters, such as the grating period, the number of grating planes, the number of laser shots for each plane, etc.…”

“…LPFGs were manufactured on photosensitive optical fibers with the point-by-point technique using an excimer KrF laser. Without any purpose to show the application of the realized gratings and in addition to the previous literature on the field [30,31], the attention of this paper will be completely focused on how all the above-mentioned manufacturing parameters strongly influence the spectral features of the grating in the transmission spectrum.…”

Fabrication of fiber optic long period gratings operating at the phase matching turning point using an ultraviolet laser

“…This is illustrated in Fig. 2, where the evolution of the resonance band corresponding to coupling to the LP 019 cladding mode in response to increasing the surrounding refractive index is simulated, using the approach described in [22] and [23], where the mode effective indices were calculated using the approach of [21], and the spectrum calculated using the matrix method of [24].…”