All-optical signal processing based on four wave mixing (FWM) in a highly nonlinear fiber (HNLF) to enhance the sensitivity of a fiber sensor is demonstrated and comprehensively reviewed in this paper. The principle is based on the frequency chirp magnification (FCM) by FWM. Degenerated FWM, cascaded two-stage FWM and pump-pulsed FWM with optical parametric amplification (OPA) are experimentall...

This paper investigates the variations of reflection spectra of embedded fiber Bragg gratings sensor in composites brought by the complicated deformation conditions, namely, strain induced grating apodization and spectrum split. The geometric change of the fiber is considered together with the strain-induced permittivity perturbations in the fiber gratings. Due to strain induced birefringence c...

The measurement of low-frequency vibration signals is a very important job in the fields earthquake early warning, health monitoring large-scale engineering structures, and geological exploration. Aiming at problem Fiber Bragg Grating (FBG) acceleration sensors’ cross-sensitivity to temperature strain when measuring signals, this paper developed an M-shaped double cantilever beam structure that...

A scheme for monitoring icing on overhead transmission lines with fiber Bragg grating (FBG) strain sensors is designed and evaluated both theoretically and experimentally. The influences of temperature and wind are considered. The results of field experiments using simulated ice loading on windless days indicate that the scheme is capable of monitoring the icing thickness within 0-30 mm with an...

Fiber Bragg grating (FBG) sensing is gaining attention in both scientific research areas and engineering applications thanks to its distinguishing advantages including wavelength multiplexing capability, miniature size, high sensitivity, immunity from electro-magnetic interference, etc. FBG sensing is based on the detection of the shifted Bragg wavelength of the light reflected by a fiber grati...

A high-speed interrogation scheme for large-scale fiber Bragg grating (FBG) sensing arrays is presented. This technique employs parallel computing and pipeline control to modulate incident light and demodulate the reflected sensing signal. One Electro-optic modulator (EOM) and one semiconductor optical amplifier (SOA) were used to generate a phase delay to filter reflected spectrum form multipl...

We proposed and studied an impact detection system based on a fiber Bragg grating (FBG) sensor array and multiple signal classification (MUSIC) algorithm to determine the location and the number of low velocity impacts on a carbon fiber-reinforced polymer (CFRP) plate. A FBG linear array, consisting of seven FBG sensors, was used for detecting the ultrasonic signals from impacts. The edge-filte...

The given paper presents the chromatic dispersion compensation scheme in WDM PON system for long haul communication consisting of the single mode fiber with the help of the FBG (fiber Bragg Grating). During the entire optimization process the major concern are provided to the vital parameter of the FBG in which the Duty cycle, the Input power , the Modulation coding , the band width of the of t...

In this work, various dispersion compensation methods are designed and evaluated to search for a cost-effective technique with remarkable dispersion compensation and a good pulse shape. The techniques consist of different chirp functions applied to a tanh fiber Bragg grating (FBG), a dispersion compensation fiber (DCF), and a DCF merged with an optimized linearly chirped tanh FBG (joint techniq...