The problems of synthesis and application of fiber Bragg gratings with special spectrum shapes in measurement and information channels of quazi-distributed fiber optic systems for climatic test systems are introduced. In particular, gratings with concave, triangular symmetric and triangular asymmetric spectrum shapes are considered, also the new poly-harmonic methods of its interrogation are presented. Projects of system decisions and results of experimental researches of its blocks are discussed.
The paper is devoted for presentation of training course for applications and construction principles of poly-harmonic (two-frequency or four-frequency) cw laser systems for characterization of different nonlinear scattering effects in fibers and reflection of devices based on fiber Bragg gratings (FBG) in down-hole telemetric sensor nets, which are widely used in down-hole telemetric systems. In particular, we’ll speak about evaluation of Mandelstam-Brillouin gain contour, Raman scattering contours and FBG reflection spectra characterization. Investigation methods and approaches are based on the unity of resonant structures of generated fiber responses on exciting and probing radiation or external physical fields for all given effects. The main decision is based on poly-harmonic probing of formed resonance responses. Training course united idea is software defined approach for down-hole parameters characterization in spite of measuring conversion principles.
This paper presents a microwave photonics method for the instantaneous frequency measurement of microwave signals,
based on the generation of a two-frequency laser radiation in the Mach-Zehnder modulator with a difference frequency
equal to the measured, and the "frequency - amplitude" conversion in the π-phase-shifted fiber Bragg grating. Frequency
measurement occurs in two ranges: 0.3 - 3 GHz in the passband of the FBG and 3 - 30 GHz in its reflection band. Using
the specific conversion of two-frequency radiation in the π-phase-shifted fiber Bragg grating allowed us to obtain measuring
characteristics, that are independent of the amplitude fluctuations of the optical carrier and to organize additional
circuit for monitoring the spectral characteristics of the used elements to reduce measurement inaccuracy caused by their
The paper considers possibility of using a system based on amplitude measurement method with a fiber Bragg grating as
a sensitive element. The features of measurement technique is application of Bragg gratings with a special spectrum
structure for different industries.
Problems of refractometric optical biosensors and courses of their fast and technological decision are considered. In particular
the resolution and sensitivity increase, formation of stable on amplitude and spectrum cleanliness probing radiation,
allocation of refractometric information from a complex of sensor parameters defined by universality of FBG response
to changes of pressure, temperature and refraction factor, construction of dot type sensors and the distributed
networks on their basis are analyzed.