Fabrication and structural analysis of ZnO coated fiber optic phase modulators

Fiber optic modulators were fabricated by coating optical fibers with electrode and piezoelectric ZnO layers. The techniques of piezoelectric fiber optic modulator (PFOM) fabrication are presented, and the microstructure and crystallographic texture of the coatings are analyzed, Ln order to produce thick (approximately 5 mu m) ZnO coatings, it was necessary to study the reactive de magnetron sputtering process in O-2/Ar gas mixtures under conditions close to the transition between an oxidized and nonoxidized Zn target surface. In situ quartz crystal microbalance measurements of the deposition rate revealed thee distinct regions in the deposition rate (R) vs oxygen partial pressure (P-o2) behavior, at constant total pressure, for sputtering under conditions that provided an oxidized Zn target surface. Additionally, a transition between oxygen and argon dominated sputtering as observed by varying the sputtering pressure while maintaining a constant P-o2. The transition between oxygen and argon dominated sputtering influences R to varying extents within the three R vs P-o2 regions for an oxidized target surface. Correlations among the cathode current and voltage, deposition rate, and gas flow rate are presented to give a better understanding of the reactive sputtering processes occurring at the oxidized Zn target surface. Sputtering conditions optimized for a high ZnO deposition rate were used to produce [001] radially oriented ZnO fiber coatings for PFOM devices that can produce optical phase shifts as large as 0.38 rad/V.

[1]  B. Khuri-Yakub,et al.  Studies of the optimum conditions for growth of rf‐sputtered ZnO films , 1975 .

[2]  J. Hrbek.  Sputtering of metals in the presence of reactive gases , 1977 .

[3]  B. Cullity,et al.  Elements of X-ray diffraction , 1957 .

[4]  D. B. Patterson,et al.  All-fiber acoustooptic phase modulators using zinc oxide films on glass fiber , 1988 .

[5]  M. Ohring.  The Materials Science of Thin Films , 1991 .

[6]  J. Musil,et al.  Influence of the pumping speed on the hysteresis effect in the reactive sputtering of thin films , 1987 .

[7]  R. Glang,et al.  Handbook of Thin Film Technology , 1970 .

[8]  W. French,et al.  Electric field sensitive optical fibre using piezoelectric polymer coating , 1982 .

[9]  A. Benninghoven,et al.  Empirical formula for the calculation of secondary ion yields from oxidized metal surfaces and metal oxides , 1977 .

[10]  G. Fox,et al.  400 MHz-bandwidth all-fiber phase modulators with ZnO coating on standard telecommunication fiber , 1996, IEEE Photonics Technology Letters.

[11]  S. Maniv,et al.  Controlled texture of reactively rf‐sputtered ZnO thin films , 1978 .

[12]  Sören Berg,et al.  A physical model for eliminating instabilities in reactive sputtering , 1988 .

[13]  H. Taylor,et al.  Acoustooptic modulators for single-mode fibers , 1987 .

[14]  F. S. Hickernell,et al.  The characteristics of coaxial ZnO thin-film BAW transducers on optical fibers , 1988, IEEE 1988 Ultrasonics Symposium Proceedings..

[15]  A. Misiuk,et al.  Highly oriented ZnO films obtained by d.c. reactive sputtering of a zinc target , 1984 .

[16]  Jacek Jarzynski,et al.  Frequency response of a single-mode optical fiber phase modulator utilizing a piezoelectric plastic jacket , 1984 .

[17]  C.A.P. Muller,et al.  Sputter deposited piezoelectric fiber coatings for acousto‐optic modulators , 1996 .

[18]  Y. Ohtsuka,et al.  Wide-frequency fiber-optic phase modulator using piezoelectric polymer coating , 1990, IEEE Photonics Technology Letters.

[19]  Kazunobu Tanaka,et al.  Growth Mechanism of ZnO Film by Reactive Sputtering Method –Significance of Thermodynamics in a Plasma System– , 1990 .

[20]  M. Sayer,et al.  Position and pressure effects in rf magnetron reactive sputter deposition of piezoelectric zinc oxide , 1984 .

[21]  M. Mermelstein,et al.  Optical-fiber copolymer-film electric-field sensor. , 1983, Applied optics.

[22]  S. Maniv,et al.  Pressure and angle of incidence effects in reactive planar magnetron sputtered ZnO layers , 1982 .

[23]  R. Behrisch,et al.  Sputtering by Particle Bombardment III , 1981 .

[24]  M. Imai,et al.  Piezoactive ferroelectric polymer jacketed optical fibers for optical phase modulation , 1989 .

[25]  G. R. Fox,et al.  Optical performance of miniature all-fiber phase modulators with ZnO coating , 1996 .

[26]  T. Yano,et al.  Piezoelectrically induced optical phase modulation of light in single-mode fibers , 1992 .

[27]  Yoshihiro Ohtsuka,et al.  Piezoelectric copolymer jacketed single‐mode fibers for electric‐field sensor application , 1986 .

[28]  K. Wittmaack.  Secondary ion mass spectrometry as a means of surface analysis , 1979 .