Newsletter

TABLE OF CONTENTS

• Tunable Optical Filters

• 2005 Site Visit

• Welcome New Faculty

• GEM Conference

• Mybeeka Cook: First GEM-STC Fellow

• Orcas Island Sea Kayaking Trip

• Graduate-Postdoctoral Advisory Council Formed

• CMDITR Spearheads Recruitment of Diversity Director

• Transitions

• REU Events

• Handbook Now Available

Low Drive Voltage Organic Fabry-Perot Etalons for Optical Modulation and Tunable Optical Filters

by Haiyong Gan, Christopher T. DeRose, Hongxi Zhang (Fallahi and Peyghambarian Research Groups, UA); and Jingdong Luo, (Jen Research Group, UW).

The Fallahi and Peyghambarian research groups at University of Arizona and Jen research group at University of Washington have successfully incorporated electro-optic (EO) polymer and hybrid sol-gel material in a Fabry-Perot etalon and achieved highly efficient optical modulation with low drive voltages. Extinction ratios of ~10dB at 5V voltage have been obtained using either AJL8/APC1,2 polymer or TCBD3/hybrid sol-gel materials. These Fabry-Perot etalons may be used as electro-optic devices such as optical switches, modulators, and tunable filters.

These results have become possible by combining the excellent performance of EO chromophores (AJL series and TCBD) synthesized by the Jen research group and the state-of-the-art optical design and fabrication techniques of the Fallahi and Peyghambarian research groups. The Fabry-Perot etalons with EO polymer/hybrid sol-gel materials have been designed using Glass/ITO/DBR/EOP/DBR/ITO/Glass structures (ITO: Indium Tin Oxide; DBR: distributed Bragg reflector and EOP: electro-optic polymer) for transmission testing and Glass/ITO/DBR/EOP/Gold structures for reflection testing. The devices have been simulated and refined using advanced optical thin-film design software. High finesse has been achieved by switching the absorptive electrodes (ITO) to outside the Fabry-Perot cavity and improving the surface quality of the Fabry-Perot etalon components. Both corona poling and contact poling have been employed to obtain good electro-optic performance. The two parallel schemes in both transmission mode and reflection mode have been applied in optical testing.

Research is underway to refine the device design in order to achieve even better optical modulation performance, including: (1) improving the electronics (with a smaller RC constant) for high speed optical modulation; (2) further improving Fabry-Perot etalon finesse for even lower voltage drive; (3) employing better performance EO chromophores with higher electro-optic coefficients and (4) improving the electric poling efficiency. Such low voltage and high speed electro-optic devices will have important applications in information technology.

1) AJL chromophores: a series of chromophores synthesized in Alex Jen (AJ) group by Jingdong Luo (L);
2) APC polymer: Amorphous Poly-Carbonate;
3) TCBD chromophore: (3-[5-(2-{4-bis-(2-hydroxy-ethyl)-amino]-phenyl}-vinyl)-thiophen-2-yl]-2,5-dicyano-4-[3-(3-hydroxy-propoxy)-phenyl]-hexa-2,4-dienedinitrile); ref: Optics Letters, 2005, (30) 117-119.

2005 Site Visit & Focus on Renewal

On June 28-29, 18 STC faculty, 19 graduate students and postdocs, 9 senior administrators, and 8 staff from six partner universities did their utmost to convey to NSF and this year’s 6 external panelists the full extent of our research, education, diversity, and knowledge transfer progress and accomplishments.

Our reviewers showed a clear appreciation of our year-3 accomplishments and changes made as part of our reorganization. They prescribed thoughtful fixes to strengthen our position going into the Class of 2002 renewal process. In particular, we have been encouraged to clarify key technical barriers in our research thrusts as well as the Center’s role in device prototyping. As a result of the Site Visit Team’s recommendations, technology transfer will figure prominently in our renewal strategy.
All members are encouraged to review the 15-page Site Visit Report which can be found in our members-only document archive. Thanks to all who participated in the review for helping to make this a constructive exercise. Special thanks to Ed Wasserman, our Strategic Advisory Board Chair, Susan Ermer of Lockheed-Martin and Franky So of Osram Opto-Semiconductors for speaking on behalf of the Center.