Polarization-independent guided-wave electrooptic interferometric modulators in lithium tantalate /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1989.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | The objective of this research is to design, fabricate, and test new polarization-independent interferometric modulators which make use of the off-diagonal tensor element (r[51]) to promote power exchange between orthogonal (TE and TM) modes in the channel waveguides. A coupled mode analysis is used to determine the refractive index change needed for extinction. A spatially periodic electric field is needed to provide phase matching between the polarization modes. The experimental results generally support design predictions. Modulators having period of 112 μm and 140 μm were fabricated using titanium (Ti) and zinc (Zn)-vapor diffused channel waveguides on Z- and X-cut lithium tantalate (LiTaO3) substrates. With Λ=0.633 μm and Λ=140 μm, a maximum modulation depth of 80% was obtained at 25 V for both polarizations from a Mach-Zehnder type interferometer realized on Z-cut substrate having 28 periods over a length of 3.92 mm when the substrate was cooled to 17.5°C from room temperature. For modulators with Λ=112 μm fabricated on X-cut substrate a maximum modulation depth of 80% was observed with 40 V at 23°C. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Electrical Engineering." |
| Physical Description: | xi, 95 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |