Oleg G. Morozov

Metrological aspects of symmetric double frequency and multi frequency reflectometry for fiber Bragg structures

In paper metrological aspects of symmetric double frequency and multi frequency reflectometry for Bragg structures are considered. Basics of this method is amplitude phase conversion of coherent single frequency radiation to double frequency and its distinguished features are frequency-shifted spectral components symmetrical position relatively suppressed frequency of initial radiation, high level of spectral purity, stable output radiation, and high conversion ratio. In paper are considered the metrological aspects of following systems: a) symmetric multi frequency reflectometry system for Bragg structures control, and b) symmetric double frequency reflectometry system for Bragg structures.

Spectrum conversion investigation in lithium niobate Mach-Zehnder modulator

A device for conversion of single frequency signal into two-frequency signal, based on lithium niobate dual-drive Mach-Zehnder modulator was proposed. The output spectrum was obtained analytically the proved numerically. The conditions for two-frequency signal generation were described.

Methodology of symmetric double frequency reflectometry for selective fiber optic structures

In paper methodological aspects of symmetric double frequency reflectometry system for fiber Bragg structure control are discussed. Amplitude phase conversion method for forming double frequency oscillations from harmonic signals is proposed. This method is based on the fact that phase modulation with certain indexes could decrease an amplitude of initial frequency and produce two symmetric side lobes. Basics of amplitude phase conversion of coherent single frequency radiation to double frequency and its distinguished features of frequency-shifted spectral components symmetrical position relatively suppressed frequency of initial radiation, high level of spectral purity, stable output radiation, and high conversion ratio are illustrated. Information structure of symmetric double frequency signal is also considered.

Theory of symmetrical two-frequency signals and key aspects of its application

We have proposed and demonstrated in recent years an unique technique to synthesize the two-frequency radiation by manipulating the amplitude and the phase of initial one-frequency lightwave. The output frequencies are symmetrical relatively to suppressed initial one and have strongly equal amplitudes and alternative phases. In this paper the principle of two-frequency radiation synthesis is summarized. The information structure of two-frequency radiation is examined and key aspects of its application are discussed concerning to the theory of precision spectral characterization of resonant structures and theory of quasi-harmonic oscillations and potential noise immunity.

Investigation and analysis of electro-optical devices in implementation of microwave photonic filters

We analyze the most effective way to obtain microwave-photonic filters coefficients, specifically implemented by electro- optical modulators. These devices are attractive to obtain desired number and sign of coefficients which results in high tunability and reconfigurability of filters. One have to decide which device will be the most appropriate in obtaining desired frequency response of the filter. The results of numerical simulations are presented for phase modulator, singleport mach-zehnder modulator and dual-port mach-zehnder modulator.

Dual port MZM based optical comb generator for all-optical microwave photonic devices

We demonstrate optical comb generator based on dual drive Mach-Zehnder modulator with tunable output spectrum and its application in ROF filters. Mathematically it has been shown how to obtain comb spectrum with adjusted number of harmonics with desired amplitudes and necessary wavelength separation. The results of numerical simulations are presented.

Instantaneous microwave frequency measurement with monitoring of system temperature

This paper presents a new two-frequency method for the instantaneous frequency and amplitude measurement of unknown microwave signal. Using the specific interaction of two-frequency radiation with fiber Bragg grating (FBG) in first version and FBG with phase π-shift in second allowed us to obtain measuring characteristics, that are independent of the energy fluctuations of the optical carrier and the microwave signal. Frequency measurement occurs in two ranges: 3-30 GHz in FBG reflection band, and in second version 0,3-3 GHz in the FBG pass band. Additional circuit for spectral characteristics monitoring of the used elements are organized to reduce measurement inaccuracy caused by their temperature instability.

RZ, CS-RZ, and soliton generation for access networks applications: problems and variants of decisions

The problems of RZ, CS-RZ and soliton generation and the problems of transmitters building for regional and intercontinental fiber optic-based solutions are proposed in order to assess their applicability and implementation of given formats and the soliton regime for the organization of access networks (1-10 Gb/s, ≤ 100 km). We have proposed and demonstrated in recent years an unique technique to synthesize the two frequency radiation by manipulating the amplitude and the phase of initial one frequency lightwave. The output frequencies are symmetrical relatively to suppressed initial one and have equal amplitudes and alternative phases. Its applications are considered.

Two-frequency scanning of FBG with arbitrary reflection spectrum

Fiber Bragg gratings are the most important elements in different fiber optics devices and are widely used both in fiberoptic communications and fiber optic sensor applications. The paper considers the integral analysis of FBG reflection spectrum (the analysis of two-frequency signal envelope). Firstly this method was supposed for studying the abstract circuit. In this paper it has been developed to analyze FBG with arbitrary shape of reflection spectrum.

Characterization of stimulated Mandelstam-Brillouin scattering spectrum using a double-frequency probing radiation

This paper presents a novel method for characterization of gain spectrum of stimulated Mandelstam-Brillouin scattering (SMBS) in single-mode optical fiber. This method is based on the usage of double-frequency probing radiation. For conversion of the complex SBS spectrum from optical to the electrical field single-sideband modulation is used. Detection of double-frequency components position in the gain spectrum occurs through the amplitude modulation index of the envelope and the phase difference between envelopes of probing and passing components.