Potential Application of Bi(Pb)-Ca-Sr-Cu-O Glasses for Preparation of Integrated Optical Fibers

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POTENTIAL APPLICATION OF Bi(Pb)-Ca-Sr-Cu-O GLASSES FOR PREPARATION OF INTEGRATED OPTICAL FIBERS Haixing Zheng and J.D.Mackenzie University of Materials Science and Engineering, University of California-Los Angeles, Los Angeles, CA 90024 The infrared transmission, and possible high nonlinear optical susceptibility of Bi(Pb)-CaSr-Cu-O glasses as well as their being the precursors for high temperature superconductors make them potential materials for integrated optical fibers. In this work, the glass formation and the fabrication of glass fibers have been investigated. The properties of the glasses have been studied. The infrared cutoff of the glasses is above 7 pm, and a high refractive index (- 2.9) and a high density (,- 6 g/cm 3) indicate the possible high nonlinear optical susceptibility. After being heat treated at high temperatures, the glasses become superconductors which show the response to the optical radiation due to the bolometric effect. Fabrication of an integrated optical fiber system incorporating the transmitting medium, optical modulator and detectors is possible. I. INTRODUCTION It is known that Bi 20 3 and PbO are conditional glass formers. In the presence of strong polarizing ions, the coordination number of Bi 3+ ions and Pb 2+ ions decrease, and [BiOn] or [PbOn] forms the glass network. Since BiP3 and Pb2÷ ions are heavy metal ions, it is expected that the glasses based on Bi 2 0 3 will have infrared transmission. Therefore, Bi 20 3-based glasses have been investigated for infrared transmitting materials [ 1,2]. It was found that PbOBi 20 3-Ga 2O3 glasses can transmit up to 7 pim. These glasses have a high refractive index of 2.3 and a high density of 8 g/cm 3. Because the nonlinear susceptibility of the oxide glasses becomes large with increasing linear index and density, PbO-Bi 2O 3-Ga 2O 3 glasses are identified with a nonresonant X3 equal to 42±7 x 10-14 esu, which is approximately three times larger than that of any glass previously reported 13]. The nonlinearity of the glasses makes it possible to use them to modulate the optical signal, such as in all-optical switching [4]. The newly discovered Bi-Ca-Sr-Cu-O glasses [5,6] are similar to the PbO-Bi 20 3-Ga 203 glasses , which only contain heavy metal glass formers. Therefore, it is expected that Bi-Ca-SrCu-O glasses will have a long wavelength infrared cutoff, which actually have been reported [7]. The glasses also are highly refractive (,-2.9) and dense (,-6.9 g/cm 3) [7,81. Therefore it is expected that Bi-Ca-Sr-Cu-O glasses will have a high nonresonant X3. Bi-Ca-Sr-Cu-O glasses, besides being good infrared transmitting materials and possible nonlinear optical materials, are the precursors for high temperature superconductors [5,6]. After heat treatment at high temperatures, the superconducting glass ceramics are formed with a transition temperature up to 110 K. It is known that superconductors can be used for optical detection over a very wide wavelength range. This has been demonstrated in granular films of both low- and high-temperat