Investigation of resonance features of microwave TE₁₁ (H₁₁) plasmatron for plasmachemical deposition in low-pressure non-isothermal plasma, formed by local resonance UHF discharge, of silica-based optical structures, doped by F and N, onto silica rods (tubes, preforms), used for special optical fibers fabrication

 

L. M. Blinov¹, A. P. Gerasimenko³,  A. P. Dolgov³, L. Yu. Kochmarev²,  V. A. Cherepenin^1, I. P. Shilov²     

                                            

¹ Kotel’nikov Institute of Radio-engineering and Electronics of RAS, Mokhovaya 11, Moscow 125009, Russia

² Kotel’nikov Institute of Radio-engineering and Electronics of RAS, Fryazino, Vvedensky Sq. 1, Fryazino Moscow region 141120, Russia

³ "Radio engineering institute of a name of the academician A.L. Mintz", îpen joint stock company

 

The paper is received on December 22, 2016

 

Abstract. In this paper we presented some results of research made on a resonator microwave plasmatron, working on H₁₁₁ mode at low oxygen pressure, to investigate its resonance features. In the beginning the setting into resonance of non-loaded resonator algorithm is described (so-called, “cold measurements”). It is carried out using adjusting quartz glass rods, placed into a resonant cavity through special holes, located equidistantly in azimuthal direction. Such setting is done at different frequencies; it sets relation between space location of rods and resonance frequency of the plasmatron at low power level. Next,an ignition of plasma is made through input to plasmatron of high microwave power from a generator having a constant frequency. In this case resonator is loaded to low-pressure, non-equilibrium UHF-discharge plasma (so-called, “hot measurements”). Monitoring results of rejected power, we adjusted resonator by quartz rods such as to achieve its minimum, which corresponds to maximum of absorbed power. We show three curves of relation between a power, absorbed in plasma, and configuration of setting rods, uniquely related in cold measurements with some resonance frequency. These frequency values are abscissas of curves points. Three curves are showed for three different values of pressure. This results confirm the assumption that plasma-loaded resonator plasmatron saves a good expressed resonance character, but with significantly increased curve’s width. Therefore, during the technological process continuous monitoring and stabilization of the resonant mode is required.

Key words:  microwave plasma, microwave plasmatron, resonance, aperture, optical fiber, silica glass, layers, doped by fluorine, microwave power, frequency.

References

1. Resonance, non–isothermal, microwave plasmochemical systems for the special silica optical fibers synthesis technology. L. M. Blinov, Yu. V. Gulyaev, V. A. Cherepenin, A. P. Gerasimenko. Zhurnal Radioelektroniki - Journal of Radio Electronics, 2014, ¹ 12, Available at http://jre.cplire.ru/jre/dec14/4/text.pdf.  (In Russian)

2. High-aperture optical waveguide structures, based on silica glass, doped by fluorine, prepared in  non-isothermal plasma of a resonance local microwave low-pressure discharge. L. M. Blinov, A. P. Gerasimenko, Yu. V. Gulyaev, A. P. Dolgov, L. Yu. Kochmarev, I. P. Shilov. Zhurnal Radioelektroniki - Journal of Radio Electronics, 2016, No. 1. Available at http://jre.cplire.ru/jre/jan16/18/text.pdf.  (In Russian)

Reference to this paper:

Investigation of resonance features of microwave TE11 (H11) plasmatron for plasmachemical deposition in low-pressure non-isothermal plasma, formed by local resonance UHF discharge, of silica-based optical structures,
doped by F and N, onto silica rods (tubes, preforms), used for special optical fibers fabrication. L.M.Blinov, A.P.Gerasimenko,  A.P.Dolgov, L.Yu.Kochmarev, V.A.Cherepenin, I.P.Shilov. Zhurnal Radioelektroniki - Journal of Radio Electronics, 2017, No. 1. Available at http://jre.cplire.ru/jre/jan17/4/text.pdf. (In Russian)