Guided-wave electrooptic modulators in tungsten-bronze ferroelectrics SBN:60 and BSTN /
The first low-loss optical waveguides have been produced in SBN:60 and BSTN by static strain. A thick SiO2 film deposited at elevated temperature and allowed to cool induces a strain at the film-substrate interface, due to a thermal expansion mismatch. Patterning the film releases a portion of the...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1995.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=742744961&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The first low-loss optical waveguides have been produced in SBN:60 and BSTN by static strain. A thick SiO2 film deposited at elevated temperature and allowed to cool induces a strain at the film-substrate interface, due to a thermal expansion mismatch. Patterning the film releases a portion of the potential energy and concentrates the strain in the substrate below the patterned strain film discontinuities. Localized refractive index changes capable of supporting guided modes result from the strain and related induced electric fields via photoelastic and linear electrooptic effects. Propagation losses for waveguides in z-cut SBN:60 of 0.7 dB/cm and 1.6 dB/cm for the TM and TE polarizations were achieved. In z-cut BSTN, values of 1.8 dB/cm (TM) and 2.5 dB/cm (TE) were observed. Electrooptic modulation via the linear electrooptic effect has been demonstrated in z-cut SBN:60 and BSTN by polarization intensity modulation (PI.M) at X=O.633um and, X=1.3um, and in x-cut SBN:60 by cutoff modulation at X=0.81um. In certain circumstances, repoling of the substrates was found to be unnecessary, despite processing temperatures well beyond material Curie temperatures. Electrooptic responses in z-cut SBN:60 and BSTN strain waveguides by PIM were larger than expected, possibly due to a modulation field enhancement caused by an irregular overlaid electrode. Modulation to 1.4 GHz with a 3 dB rolloff near 1 GHz has been observed in SBN:60 at X=1.3um. |
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| Item Description: | Vita. "Major Subject: Electrical Engineering". In title, numerals are used. |
| Physical Description: | xiv, 117 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |