Albert Kh. Sultanov

Outdoor

This letter proposes a W-band hybrid photonic wireless link based on a commercial small form-factor pluggable (SFP+) module and experimentally demonstrates its performance. Using a free running laser as local oscillator and heterodyne photonic upconversion, good frequency stability is achieved. Outdoor wireless transmission over 225 m with a bit error rate below 10-6 is demonstrated, and the maximum reach of the system with typical RF components is calculated, finding wireless distances above 2 km to be feasible. Being based on a commercial SFP+, the proposed hybrid photonic wireless link offers seamless integration with existing distribution networks and passive optical networks, and thus paves the way for future mobile frontand backhaul architectures.

W

Transmission of optical beams with phase front vorticity through relevant distances in optical fibers poses a problem of time-dependent intermodal interference with random complex coefficients. In this paper we propose a method for compensation of interference between LP-modes, propagating through the optical fiber. To implement optical-domain modal filtering, reconfigurable diffractive optical element matched with particular modes is considered. Such an element may be encoded as phase-only hologram by means of SLM. With this approach modes can be separated spatially in the compensating diffractive element far field and handled independently with corresponding complex coefficients. Efficiency of the proposed method is confirmed by computer simulation results.

-Band Hybrid Photonic Wireless Link Based on an Optical SFP+ Module

Hybrid optoelectronic landmark navigation is proposed as backup navigation for Low Earth Orbit satellite. Optoelectronic navigation can use earth observation camera, originally not assigned for navigation purposes. The concept of the landmark navigation system is based on the onboard optical correlator application for real time matching of the earth images and pre-recorded images of landmarks with known coordinates. The software model of image processing by optical correlator has been developed to test the system operation in simulated experiments and to estimate the expected performance. The hardware model of the joint transform optical correlator has been manufactured and tested. The model uses commercially available optoelectronic components and works with PC, which performs all digital processing and data flow control. As a result ofthe model testing, the feasibility ofthe system concept and the adequacy ofthe software model have been proved. The image processing system which calculates satellite attitude and position on the base of correlation peaks measurements has been used for simulation of optoelectronic satellite landmark navigation. In the series of simulated experiments the navigation accuracy was estimated in presence of image distortions and noise for earth observation mission.

Adaptive SLM-based compensation of intermodal interference in few-mode optical fibers

The paper describes the application of IR-UWB technology for organizing the radio part of Radio-over-Fiber system. Four physical layer components are proposed and designed in the paper: three microstrip filters and UWB antenna. Firstly the effective SCRF mask was calculated to ensure electromagnetic compatibility with existing radio services. Then this mask was considered as a cost function for filters design. The simulation was made with Agilent Genesys™ and CST Microwave Studio. All the devices have shown good performance and could be implemented on one circuit board for reducing losses.

Simulation of satellite landmark navigation on the base of optoelectronic image processing technique

Wireless part of the laboratory bench, implementing IR-UWB Radio-over-Fiber system, is described in the paper. Experimental prototype of fractal antenna radiating system (FARS) is considered, various transmission modes of the laboratory bench, which allow to investigate technical specifications, are described. Research results are presented and analyzed.

IR-UWB radio-over-fiber system components development

Experimental bench, which provides high-speed data transmission for IR-UWB Radio-over-Fiber systems on the basis of Gaussian pulses, is presented in the paper. Experiment setup and results are described and discussed.

Experimental study of wireless part of laboratory bench, implementing IR-UWB radio-over-fiber system

The device for positive chirping of a signal in a fiber optical line is offered. The device is based on two Fabry–Perot resonator with additional fiber optical cannels. If to execute the amalgamator from an erbium doped material, the device will supply amplification of a target signal, which is important for distribution access systems (for example, Radio-over- Fiber systems (RoF)). The device provides selectivity for spectral components of entrance radiation, that allows to operate of chirp. Built-in the converter of length provides in additional fiber optical cannels tuning the chirp under the given size.

Experimental demonstration of high-speed data transmission based on Gaussian pulses for IR-UWB radio-over-fiber systems

In this paper we demonstrate computer simulation results obtained for the coherent mode division multiplexed (MDM) 5x5 QPSK transmission using principal modes (PMs) of the stepped-index few-mode fiber (FMF) as a basis of independent signal carriers. The output signal recovering and the fiber propagation matrix determination are considered to be carried out in optical domain by means of reconfigurable multibranch diffractive optical elements (DOEs). Both the cases of Gaussian and Nyquist raised-cosine pulse shaping are considered for optical signal modulation. The simulation results show, that the transmission in the basis of PMs in strong coupling regime allows the reliability of the coherent MDM system to be fundamentally improved. As a result, utilization of the optical signal processing for MDM transmission could minimize substantially the DSP circuit complexity required for the real-time recovering of the transmitted signal.

The fiber optic device for signal positive chirping by interferential method with tuning of chirp size

The article is devoted to the development of an automatic system for switching fiber-optic communication lines to a reserve in the event of emergency situations using switches controlled by a decision device. In the development section, a description of the optical communication line with automatic redundancy is provided by the operation of the decision device using a transfector based on logic elements made on a GaInAs crystal. In the practical part, a simulation of the optical communication line and the decision device with the matched parameters in the OptiSystem program was made. Waveforms and signal patterns of the signal on the main and backup lines are presented.

Simulation of the coherent MDM transmission using principal modes of the optical fiber as signal carriers

In this paper we consider nonlinear impairments of mode division multiplexed signals with QAM modulation in optical fibers with linear mode coupling of spatial modes. We simulate simultaneous propagation of fundamental mode and two first-order vortex modes in standard single mode fiber at 850 nm and propagation of fundamental mode and first- and second-order vortices in step-index fiber with enlarged core at 1550 nm. Simulation results shows that in strong coupling regime linear coupling lead to sufficient increasing of nonlinear impairments, but QAM-modulated signal is more robust to this effect than OOK modulated signal.