Performance optimization of apodized FBG-based temperature sensors in single and quasi-distributed DWDM systems with new and different apodization profiles

Abstract

In this work, different FBG temperature sensors are designed and evaluated with various apodization profiles. Evaluation is done under a wide range of controlling design parameters like sensor length and refractive index modulation amplitude, targeting a remarkable temperature sensing performance. New judgment techniques are introduced such as apodization window roll-off rate, asymptotic sidelobe (SL) decay level, number of SLs, and average SL level (SLav). Evaluation techniques like reflectivity, Full width at Half Maximum (FWHM), and Sidelobe Suppression Ratio (SLSR) are also used. A “New” apodization function is proposed, which achieves better performance like asymptotic decay of 18.4 dB/nm, high SLSR of 60 dB, high channel isolation of 57.9 dB, and narrow FWHM less than 0.15 nm. For a single accurate temperature sensor measurement in extensive noisy environment, optimum results are obtained by the Nuttall apodization profile and the new apodization function, which have remarkable SLSR. For a quasi-distributed FBG temperature sensor the Barthann and the new apodization profiles obtain optimum results. Barthann achieves a high asymptotic decay of 40 dB/nm, a narrow FWHM (less than 25 GHZ), a very low SLav of −45.3 dB, high isolation of 44.6 dB, and a high SLSR of 35 dB. The new apodization function achieves narrow FWHM of 0.177 nm, very low SL of −60.1, very low SLav of −63.6 dB, and very high SLSR of −57.7 dB. A study is performed on including an unapodized sensor among apodized sensors in a quasi-distributed sensing system. Finally, an isolation examination is performed on all the discussed apodizations and a linear relation between temperature and the Bragg wavelength shift is observed experimentally and matched with the simulated results.

Investigation of the Effect of FBG Profiles, Temperature and Transmission Distance for Environmental Sensing & Monitoring

“…Detection of non-physical parameters requires the FBG to be modified by coating the sensitized region with a reversibly reactive material nanostructures that can induce mechanical strain or reaction to the FBG when exposed to a measurand [16]. Generally, it is possible for a FBGs to sense chemical parameters such as salinity concentration [8], chemical gas concentration [17] and relative humidity of the environment [18]. Ease of modification of FBG to suit various environmental sensing applications makes FBG a viable sensing device to be studied and optimized.…”

“…Specifically, in gausian apodized FBG, the grating intensity change along the grating length follows Gaussian modelling variant of the original Bragg wavelength equation. The emergence of this type of grating profile serves to reduce side lobes that may appear on uniform grated FBG [8]. Apodized FBG are also known to result in more narrow peaks of both reflectivity and transmission spectra.…”

“…Since the proposed harvester design provides a low but steady power output to act as a light source, the whole FBG system will be run under low power to be simulated within various ASTESJ ISSN: 2415-6698 conditions including thermal and attenuation. It is an opportunity to simulate how well the system of FBG can be run with sufficient power with different types of gratings which differs from most other closely similar articles involving FBG simulation [7][8][9].…”

Design and performance evaluation of a dispersion compensation unit using several chirping functions in a tanh apodized FBG and comparison with dispersion compensation fiber

“…Among these, the FBG has attracted huge interest for the design, testing, and evaluation of dispersion compensation units, as its effectiveness is due mainly to its complete passiveness, compactness, relatively low cost, low insertion loss, fiber compatibility, and lack of nonlinear effects [8]. Note that FBG is used in a huge range of optical telecommunication applications other than dispersion compensation, such as fiber laser reflectors [9,10], wavelength division multiplexing (WDM) devices [11], optical pulse compression [12], tunable optical delay [13], optical filters [14,15], optical signal generation/shaping [16][17][18], and optical sensors [19,20].…”

Optimum apodization profile for chirped fiber Bragg gratings based chromatic dispersion compensator

“…One of the methods to compensate HC-PCF's GVD is to use apodized Chirped Fiber Bragg Gratings (CFBG) [2]. Several researches focused on optimizing the apodization profile to improve the performance of CDC at 1.55 μm wavelength [3][4][5]. Selection of the best parameters for the CFBG such as grating length, chirp period and index variation is very important.…”