A.А. Bortsov, Yu.B. Il-in

The opto-electronic oscillator (OEO) with a fiber-optical line of a delay is perspective RF source. The OEO is used as the setting generator in devices of radio- and optical локационных complexes, and also in systems of formation and processing of optical and electronic precision signals. Experimental results of measurements of spectral density of capacity of phase noise the OEO equal-147 Db/Hz on frequency of generation of 10 GHz at standard отстройке 1 kHz. It allows to conclude that the OEO competes with small noise generators to dielectric resonators on sapphire crystals on frequencies of generation 8 - 70 GHz. At the same time, the question of influence of parametres of optical radiation of the laser or the laser diode of a base element the OEO on spectral characteristics of generation of radio-frequency fluctuations is a little studied. The work purpose is definition of spectral density of peak and phase noise radio-frequency the OEO and its dependences on width of a spectral line of radiation and capacity of optical radiation of the laser. The laser in the OEO is a rating for RFO. RFO it is formed, consistently closed to a feedback ring the electro-optical modulator Maha- Zender , fiber-optical system , the photo diode , the nonlinear amplifier , the radio-frequency narrow-band filter. In the present work the OEO as system of two various types of generators - the optical quantum oscillator (OQO) with frequency of generation approximately 200 THz and the radio-frequency oscillator (RFO) with frequency of generation 4-100 GHz is considered. The optical quantum generator thus is a source of a rating for the radio-frequency generator. In both generators their spectra are formed by the fluctuations having the different nature, and the final width of a spectral line is defined by parametres of two resonant systems - the laser and RFO. Interesting feature the OEO is that the spectrum of radio-frequency fluctuations of generation is formed not only noise having the electronic nature, but also phase fluctuations of optical radiation of the laser which have the quantum nature and are defined by spontaneous radiation of the laser. The approach to consideration the OEO as sets of two self-oscillatory systems with dissipation and with a dispersive line of the delay formed OQO and RFO is productive. It gives the chance to analyse influence of elements of the laser on RF noise the OEO , to investigate management of a spectrum of laser RCH of a signal the OEO , to study synchronisation the OEO an external optical source of radiation, etc. In work for the description of noise properties the OEO is considered system the fluctuation equations for OEO and RFO. On the basis of the decision of systems of the equations for OEO with fluctuations within the limits of semi-classical for intensity of radiation and its phase of the laser dependences of spectral density of capacity of phase noise of the laser are received. The given dependences are functions of a constant of time of the resonator of the laser and capacity of radiation of the laser. Using linear model of the fiber optic line of delay, it is made the fluctuation differential equation for the OEO. After carrying out of operation of shortening on fast movements it is solved truncated the fluctuation equation for the OEO . Dependences spectral density of phase noise of RF phase fluctuations on width of a spectral line of the laser and capacities of the laser are received. It is established that, on the one hand, at the big difference of delays in channels of the modulator Maha Zender, the OEO can be used as a measuring instrument of width of a line of the laser and . On the other hand, at use the OEO in quality small noise RFO (for example, spectral density of capacity of phase noise the OEO of 10 GHz equal-147 Db/Hz on frequency of generation at standard shift 1 kHz) the width of a spectral line of the laser of a rating should be minimum at a small difference of delays in modulator channels. Thus and reduction RF of spectral width of a line the OEO concerning a laser line occurs for the account coherent photoreception with FM modulation on an optical phase, high good quality of oscillatory system. In work results of computer modelling the OEO with dispersive and non-dispersive line of delay are stated. As a result of research of dependences conclusions are drawn that spectral density of phase noise of RF fluctuations of the OEO makes on spectral density of phase noise considerable impact the noise connected with FM conversion. It is shown that expansion of a spectral strip of radiation of the laser leads at the expense of a dispersion of a fiber optical path to substantial increase spectral density of phase noise of RF fluctuations of the opto-electronic oscillator the OEO at a strip of the laser comparable with a radio frequency of generation the OEO . In the given work the OEO of range on frequency of generation of 8,2 GHz is experimentally investigated. Experimental dependences will well be coordinated with settlement at the account of stabilisation effect at the large currents of rating laser diode and lengths of a fiber optical path more than 5 km.