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Your search keyword '"Medvedkov, O I"' showing total 28 results
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28 results on '"Medvedkov, O I"'

1. Erbium-Doped Fibre as a Sensitive Element of the Cryogenic Temperature Sensor

Author

Dianov, E. M., Kurkov, A. S., Medvedkov, O. I., Sergei Vasiliev, Baykin, D., Bender, S., and Koretsky, A.

Abstract

Fibre-optic temperature sensors for the cryogenic temperature range can be efficiently used for the control over low temperature superconductor devices. Temperature monitoring of such devices is necessary to avoid its failure. We propose a new type of fibre-optic cryogenic temperature sensor. Its operation principle consists in measuring changes in optical losses of erbium-doped fibres, which occur owing to narrowing of the absorption spectrum of Er3+ ions with decreasing temperature.

Published
1998
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2. Application of Photoinduced Long-Period Fiber Gratings in Optical Sensors

Author

Dianov, E. M., Kurkov, A. S., Medvedkov, O. I., and Sergei Vasiliev

Abstract

At present the photoinduced in-fiber Bragg gratings are widely used as a sensitive element of optical fiber sensors. Their operation is based on the vanation of the reflection peak under an outer action. The sensitivity of silica glass to variations of temperature or applied strain is very small, therefore the operation of sensors based on the Bragg gratings are possible only due to the narrowness of the reflection peak. We propose to apply die pholoinduced long-period cladding-mode-coupled fiber grating as a sensitive element of optical fiber sensors The sensitivity of this type of the grating can be increased by its loading in an additional medium.

Published
1996
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5. Powerful fibre SRS lasers emitting in the 1.22-1.34-μm range

Author

Kurkov, A. S., Dianov, E. M., Paramonov, V. M., Gur Yanov, A. N., Laptev, A. Yu, Khopin, V. F., Umnikov, A. A., Vechkanov, N. I., Medvedkov, O. I., Vasil Ev, S. A., Mikhail Bubnov, Egorova, O. N., Semenov, S. L., and Pershina, E. V.

6. Highly efficient one- and two-cascade Raman lasers based on phosphosilicate fibers

Author

Bufetov, I. A., Mikhail Bubnov, Larionov, Y. V., Medvedkov, O. I., Vasiliev, S. A., Melkoumov, M. A., Rybaltovsky, A. A., Semjonov, S. L., Dianov, E. M., Gur Yanov, A. N., Khopin, V. F., Durr, F., Limberger, H. G., Salathe, R. -P, and Zeller, M.

Subjects
[OFD], Physics::Optics, Astrophysics::Earth and Planetary Astrophysics, Physics::Atomic Physics
Abstract

Characteristics of one-cascade (1.06 double right arrow 1.24 mum) and two-cascade (1.06 double right arrow 1.24 double right arrow 1.48 mum) phosphorus-doped fiber Raman lasers are studied. The cavities of both lasers are formed by Bragg gratings written directly in the active fiber. Double-cladding Yb3+ and Nd3+ ion fiber lasers with lambda similar to 1.06 mum were employed for pumping. These lasers were pumped, in their turn, by diode laser arrays with lambda similar to 0.98 mum (Yb) and lambda similar to 0.81 mum (Nd). The efficiency of the one-cascade laser with an unprecedentedly short length of 50 in was as high as 65% with 4.8-W pump radiation applied to the input of the laser. The maximum efficiency of the two-cascade Raman fiber laser was 40%. Gratings directly written in the active fiber reduced concentrated losses in laser cavities, which allowed the laser length to be decreased and the lasing threshold power of Raman fiber lasers to be lowered.

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