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Electroabsorption modulators (EAM) have attract a lot of interests in high-speed optical communication due to low chirp, high-efficiency operation and the capability to be integrated with other semiconductor devices. Enhancing the operation by overcoming the trade-off between RC-limitation and high-speed performance, traveling-wave types of EAMs (TWEAM) have been documented to be a good candidate. In this thesis, a novel type of TWEAMs, namely undercut-etching-the-active-region type (UEAR), have been characterized and analyzed. There are two topics in this thesis, namely (1) one is to compare the performance of the UEAR and conventional ridge-waveguide (RW) types of TWEAM. The regime of D.C. to 40GHz small-signal modulation and 10 Gbits/sec large-signal data transmission are used to characterize and compare the performance of TWEAMs. In comparison with conventional ridge-waveguide (RW) TWEAM, 3dB lower optical-insertion-loss, at least 6dB higher in RF-link (D.C. to 40GHz) and faster electro-optical response (3dB bandwidth of 25GHz at 50£[-termination for UEAW and 15GHz for RW) are obtained in UEAW-TWEAM. Error-free 10Gbits/sec operation with high sensitivity of ¡V36.2 dBm and low swing voltage of 0.6V have been achieved in UEAW-TWEAM, a 3.2dB enhancement over RW-TWEAM, indicating the trade-off in designing electroabsorption modulators can be greatly released by novel type structure (UEAW). (2) The other topic is the application of TWEAM to all-optical wavelength converters. The generating photocurrent by optical absorption is the effect accompanying with the electrical-to-optical modulation in the EAM. Using the properties of cross-absorption and generating photocurrent, high-speed all-optical modulation can be potentially implemented in the application of EAMs. Long -waveguide high-speed TWEAMs can thus have high-extinction ratio performance in all-optical conversion. The conversion efficiency of -26dB and high extinction ration of >20dB are obtained in this experiment, showing the potential in the application of all-optical conversion.

All-optical wavelength conversion is necessary for efficient managing and routing optical signals in a complex all-optical network model. With the bit-rate increases as time evolves, all-optical conversion will become more promising due to its high transparency for data rate and format and the low cost penalty compared with O/E/O method. Periodically poled LiNbO3 crystal fiber (PPLNCF) for wavelength conversion is successfully grown by LHPG method with in situ electric field bias. The pitch depends on the frequency of applied external electric field. Domain period of 9.76 microms and crystal length over 160 mm are demonstrated in this thesis. Electrically induced micro-swing during growth is managed to assist poling process. After the optical test, 0.27% peak offset shows the accuracy of our fabrication. The wavelength and temperature bandwidths were measured to be 17.2 nm and 42.8oC. With the improvement of uniformity, broadband design, and the implementation of guiding structure, high quality PPLNCF will be widely promoted for its superior performance.

Thesis. / Includes vita. Includes bibliographical references (leaves 128-134)

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed on Jan 23, 2007). PDF text: 303 p. : ill. (some col.) ; 2.13Mb. UMI publication number: AAT 3216338. Includes bibliographical references. Also available in microfilm and microfiche format.

Thesis (Ph.D.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves129-138)