Fiber Bragg Gratings or FBGs have achieved significant attention towards sensing and communication applications due to their outstanding advantages. Due to its high sensitivity towards various design parameters, it is now widely used to measure different physical and chemical parameters in various industrial sectors, including harsh environment applications. This review presents a comparative study of different FBG-based temperature and strain sensors reported in recent years. The analytical formulation for such sensors is also presented in brief. Necessary numerical simulation results are incorporated. For FBG based temperature sensors, both low and high range are considered. Similarly, for FBG-based strain sensors, both uniform and non-uniform strain are considered and discussed in brief. Apart from the sensing applications, new variants of FBG like secondary gratings and Random Optical Grating by Ultraviolet or ultrafast laser Exposure (ROGUE) gratings are also discussed.

Recent advancements in fiber Bragg gratings based temperature and strain measurement

Today’s access networks are in high demand to fulfill the high bandwidth requirement because of extensive improvement in high transmission rate applications for cloud computing, big data analytics, and other next-generation 5G smart applications. This exponential growth of high capacity and broadband access technologies comprise an essential trend in the development of a passive optical network (PON) access network. In this paper, 80/80 Gbps time wavelength division multiplexing PON (TWDM-PON) incorporating polarization division multiplexing (PDM) based Mach–Zehnder modulator (MZM) and electroabsorption modulator (EAM) techniques have been proposed. The performance of the system consisting of different polarized multiplexed modulation techniques is investigated in both downstream and upstream data transmission for variable transmission distance and received optical power in terms of bit error rate (BER), eye diagrams, power budget (PB) and receiver sensitivity. The results show that the 4 × 20/20 Gbps PDM-EAM modulated signals over 100 km fiber distance at − 60 dBm RS and 70 dB PB are successfully transmitted under fiber non-linearities. The proposed TWDM-PON system provides a next-generation long-reach access network from urban to rural areas.

Performance Evaluation of Symmetric 8 × 10 Gbps TWDM-PON Incorporating Polarization Division Multiplexed Modulation Techniques Under Fiber-Impairments

In this paper, new symmetrical and post dispersion compensation schemes are proposed and investigated. Each scheme has many cases. Each case has a certain connection for the proposed model used in narrowing the linewidth, Δλ, of the optical signal. The new schemes in WDM systems are implemented and simulated with Optisystem 15 up to 200 km. The new proposed schemes are evaluated through the Q-factor and BER, showing a performance enhancement by 21% in the symmetrical and 19% in the post compensation as compared to the previous work.

Symmetrical and post dispersion compensation in WDM optical communication systems

In this paper, we compare the characteristics of several waveguide Bragg gratings (WBGs) with sinusoidal and rectangular corrugated sidewalls in high confinement integrated optics. Our measurements confirm the performance of both the rectangular and sinusoidal grating as band-rejection filters for TE-polarized signals in the telecom C-band. These measurements demonstrate record high extinction ratios of 35 and 28.91 dB for sinusoidal and rectangular WBGs with a rejection bandwidth as narrow as 4.42 and 6.165 nm. The simulation results and measurements show that the filter bandwidth and coupling coefficient can be changed by altering the corrugation width ([Formula: see text]), allowing us to control the filter’s quality factor precisely. The bandwidth of rectangular WBGs drops for [Formula: see text] nm, constraining the design of devices requiring broadband WBGs. In contrast, the bandwidth of sinusoidal WBG continues to increase for [Formula: see text] nm, providing a wider bandwidth for designers. These findings demonstrate the potential for effective integration of new photonic functionalities into low-footprint electro-optical waveguide tools for sensing, communicating, and computing applications.

Sinusoidal and rectangular Bragg grating filters: Design, fabrication, and comparative analysis

By the discovery of the optical fiber, it has become the most widely used technique for communication purposes. The major limiting factor which degrades the efficiency of optical communication is the dispersion, as it causes the traveling pulse along the fiber to spread and change its shape causing inter symbol interference. The main objective of this paper is to reduce the dispersion effects. This is carried out by using four cascaded tanh apodized FBGs, which is the main contribution in our work, to enhance the spectral linewidth of light source as it works like a band pass filter that reflects a certain signal wavelength and passes the others. A maximum bit rate per channel of 709.9905 Gbit/s is achieved in silica-doped optical fibers based on the maximum time division multiplexing (MTDM) transmission technique at a temperature of 20 °C, a relative refractive index difference of 0.002, a doping ratio of 0.2, a signal wavelength of 1.65 µm and a 10 km link length. Three conditions are considered and compared in our work: MTDM technique only, MTDM with raised cosine apodized FBG, and MTDM with tanh apodized FBG.

Dispersion compensation analysis of optical fiber link using cascaded apodized FBGs hybrid with maximum time division multiplexing transmission technique

In this paper, a cascaded fiber Bragg grating (FBG) system is proposed to reduce the dispersion in the optical signal in single mode optical fibers. This consequently enhances the system performance, which is evaluated by the bit error rate (BER) and quality factor (Q-factor). The proposed model consists of four uniform cascaded FBGs connected at the transmitter to get narrow linewidth, Δλ, of the optical signal, which is a major cause of the delay. The Optisystem7 is used to simulate the proposed model in a WDM system with and without the model for distance 200 km. The system parameters are investigated showing an enhanced performance with 12%, including eye diagram, Q-factor and BER. A 10−6–10−10 BER is achieved with a quality factor in the range 7–14, including the effects of fiber length, input power and FBG length.

An enhanced WDM optical communication system using a cascaded fiber Bragg grating

Apodized chirped fiber Bragg grating for postdispersion compensation in wavelength division multiplexing optical networks

This paper proposes a system that aims to reduce the spectral width, Δλ, of the optical signal at transmitter for WDM system over distance 100 km. Also, a chirped fiber Bragg grating (CFBG) at the receiver is used to compensate dispersion. The proposed system consists of four cascaded FBGs connected between light source and optical fiber. Many apodization functions are investigated to enhance the performance of the FBG in the proposed system, and Δλ is obtained at every stage and apodization function. The Q-factor and bit error rate (BER) are obtained at distances 30, 40 and 50 km. It is found that Cauchy apodization function is the best one that reduces the reflective spectral width, Δλ, and achieves a maximum Q-factor and minimum BER at distances 30, 40 and 50 km at the last stage.

Spectral width reduction using apodized cascaded fiber Bragg grating for post-dispersion compensation in WDM optical networks

Developing trust in 5G network slicing is an important issue since as mobile networks evolve the number of internal components, network functions, and the use of virtualized elements increase. The current security practices that are based on a perimeter/defense-in-depth cybersecurity approach are proven to be ineffective to address the current and future cybersecurity challenges because they assume that everything on the inside of a network is trustworthy. One promising approach of growing significance in the telecom security sphere is the Zero-Trust (ZT) security model. This paper opens a new research direction for implementing a real-time ZT framework that enables trustworthy deployment and secure management of network slices in 5G open architecture.

Ahmed F. Sayed

Papers

An enhanced WDM optical communication system using a cascaded fiber Bragg grating

Apodized chirped fiber Bragg grating for postdispersion compensation in wavelength division multiplexing optical networks

Spectral width reduction using apodized cascaded fiber Bragg grating for post-dispersion compensation in WDM optical networks

Symmetrical and post dispersion compensation in WDM optical communication systems

Toward Zero Trust Security IN 5G Open Architecture Network Slices