Organic Electro-Optic and All-Optical Materials and Devices

In this area, we collaborate closely with participants in both the NSF-funded Science & Technology Center and the DARPA-funded Molecular Photonics program to develop “transformative” electro-optic (EO) and all-optical (AO) materials and devices for light-weight, low drive voltage, and ultrahigh-speed information processing. The goals are to: 1) develop organic materials with ultrahigh E-O and c 3 activities and optimized thermal, mechanical, and photochemical properties; integrate organic E-O materials into novel device structures; 2) demonstrate low-power, ultrahigh bandwidth signal processing devices; 3) d emonstrate ultra-wide bandwidth emitter-sensor pair that will dramatically improve spectroscopic applications in the THz regime (>5 THz).

These challenges inspire us to take an integrated approach to d evelop novel materials and facile processing methods to make polymer, polymer/Si, and THz waveguide devices. These efforts will generate very significant impact on producing devices with very high bandwidths and low drive voltages for applications in high-speed telecommunications, microwave photonics, and defense and homeland security sectors.

 


Integration from Materials to Systems

 

1. Supramolecular Engineering to Achieve Ultrahigh E-O activity (15 times higher than the commercial LiNbO3)

The correlated experimental and theoretical effort facilitated the development of highly nonlinear chromophores and dendrimers. The following figure shows an example of such a novel material and an idealized model of the supramolecular self-assembly of hydrogen- and fluoro-containing dendrons that resulted in excellent poling efficiency and alignment stability. Such a high electro-optic activity is a new paradigm to revolutionize information technology with ultrahigh speed and very large bandwidth. Future work will be focused on 1) exploring new supramolecular material architectures (working with theorists) with the aim of increasing acentric order parameters and perhaps even achieving perfect ferroelectric order; 2) improving long-term thermal stability (at 85 ° C) and mechanical properties of these materials through tuning the supramolecular interaction forces or introducing smartly-controlled lattice hardening in order to incorporate them into the novel photonic structures.

 

 

2. “Click Chemistry” of Diels-Alder reactions for nanostructured EO dendrimers and polymers

 


Lattice hardening is critical to both thermal stability and multilayer processing of EO polymers. A new approach for hardening E-O polymers during the poling process has been developed. This involves the “Tunable Diels-Alder” reaction.With this reaction, lattice hardening can vary from reversible crosslinking to irreversible crosslinking depends on the processing conditions and needs. The successful development of these protocols has led to hardened materials with long-term thermal stability at 85 ° C-100 ° C and low optical loss. Future work will be structural optimization of high bm polyene chromophores to enhance their thermal stability to 200 ° C or above. The ultimate outcome of this joint effort is the production of materials that appear to fully meet Telecordia standards.

 

3. Third-Order Organic NLO Materials for All-Optical Signal Processing and Switching (Collaborating with Joseph Perry and Seth Marder @ Georgia Tech)

Third-order nonlinear optical (NLO) materials have attracted attention because of potential utilities for photonic applications such as ultra-fast optical switching and modulations. To be practically useful for all-optical switching, materials should have large third-order susceptibilities c (3) at the operating wavelength, typically at 1300 to 1550 nm, ultra-fast response and relaxation times (picoseconds or less), minimal absorption loss (non-resonant nonlinearity), and good environmental stability and processability. However, few organic materials reported to date offer a combination of the large nonlinearity in the near-infrared region (NIR), response time in picoseconds, and good film-forming properties. Strategies that have been pursued to increase third order nonlinearity include extending conjugation length in polymers such as polyacetylene and its derivatives, introducing donor and acceptor terminal sets separated by a pi-conjugated system, and optimizing the bond length alternation in donor-acceptor conjugated molecules.

 

4. Synthesis of Electro-Optic Dendron-Coil Block Copolymers and Dendronized Polymers

A variety of NLO chromophore-containing dendron-coil block copolymers and dendronized polymers have been prepared and shown to lead to significant (e.g., factors of 2 or 3) improvements in E-O activity compared to the same chromophores existing in chromophore/polymer composite materials. Values exceeding 160 pm/V have been achieved for ordinary chromophores. Such materials have also been found to lead to improved optical transparency (reduced optical loss due to better compatibility between chromophore and matrix or much smaller size nm-phase separation) and to improved stability (both thermal and photochemical). Important integrated activities between nanometer-scale materials synthesis and processing and the statistical mechanical calculations of the theory have resulted in dramatic improvements in ferroelectric chromophore order (acentric order parameters). Future work will focus on incorporating new and improved chromophores into currently identified dendron and dendronized polymer architectures. The new integrated theory/synthesis team effort would seem a sure-fire approach to the realization of our objectives.

 

5. Polymer Integrated Optical Devices through Soft Lithography (Collaborating with Amnon Yariv @ Caltech)

Develop simple, non-expensive, and precise lithographic process to fabricate channel waveguides for integrated optical devices. Employ soft lithography to imprint sophisticated channel waveguide structures and provide a simple process for the mass production of devices. Both active (E-O Mach-Zhender modulators) and passive (micro-ring filters and AWGs) have been demonstrated by this process with high degree of replication of the master structures.

 

6. Hybrid Sol-gel/Polymer Waveguides (Collaborating with Nasser Peyghambarian, Mamoud Fallahi, and Robert Norwood @ University of Arizona)

Hybrid polymer/sol-gel waveguide modulators have been successfully fabricated and packaged with optical fibers to demonstrate the feasibility of combining high EO activity of organic materials and low optical loss (absorption and insertion) of glass waveguide in the same system for integrated EO devices. The hybrid approach combines a photo-patternable hybrid organic-inorganic sol-gel material with active NLO chromophores for fabricating low-loss, highly reliable modulators at 1550 nm. This approach enables simple processing, low cost, and ease of fiber coupling and packaging. Single-mode E-O active waveguides with low loss (<1 dB/cm at 1550 nm) were achieved by reverse channel patterning of sol-gel. The insertion loss of the packaged device (7-8 dB) is the lowest among all EO polymer-based modulators and is quite comparable to that of the commercial low loss LiNbO3 modulator. Very low drive voltage has been achieved very recently to be ~1.0 V at the wavelength of 1550 nm.

 

 

7. Terahertz Signal Generation and Detection (Collaborating with Michael Hayden @ Univ. Maryland , Baltimore County)

The THz work focuses on two important applications: 1) the development of a THz emitter-detector pair that has significantly wider bandwidth (> 10 GHz) than is currently available and (2) the development of waveguide THz emitters for efficient generation. The goal is to develop an ultra-wide bandwidth emitter-detector pair that will revolutionize spectroscopic applications in the THz regime. The successful development of these devices will have very significant impact on applications in homeland security, defense, and medical information and diagnostics. Recently we have successfully demonstrated generation and detection of terahertz signals utilizing thin film organic EO polymers. The EO polymer-based device has shown 300 times higher intensity than the best inorganic material, ZnTe crystal.

 

8. Fabrication of Devices by Nanoimprinting Lithography (with Axel Scherer @ Caltech and Larry Dalton @UW)

 

Text Box:

 

Nanoimprinting lithography (NIL, also known as embossing lithography) has been developed as an alternative to conventional photolithography because it can provide the same processing capabilities without using photoresists and the solvents associated with their processing. Sub-100 nm features can be reproducibly stamped and the entire process is clean room compatible. The solvent-less aspect of NIL makes it a very attractive technique for processing organic EO materials because of their sensitivity to solvents during multilayer processing. By employing one of the reversibly crosslinkable Diels-Alder polymers, PSDA, which was developed in our group, we can imprint the polymer in an e-beam written photonic crystal stamp at its initial Diels-Alder dissociated state because it possesses much lower viscosity. When the stamp was cooled down, the polymer returned to its crosslinked state and became hardened. The final result is a robust, highly customizable, EO polymer system that can be imprinted with nanoscale fidelity at a much lower temperature (120 °C) than the usual decomposition temperature of NLO chromophores.

 

9. Terahertz all-optical modulation in a silicon–polymer hybrid system (Collaborating with Axel Scherer @ Caltech and Larry Dalton@ UW)

Although gigahertz-scale free-carrier modulators have been demonstrated in silicon, intensity modulators operating at terahertz speeds have not been reported because of silicon’s weak ultrafast nonlinearity. We have demonstrated intensity modulation of light with light in a silicon–polymer waveguide device, based on the all-optical Kerr effect—the ultrafast effect used in four-wave mixing. Direct measurements of time-domain intensity modulation are made at speeds of 10 GHz. We showed experimentally that the mechanism of this modulation is ultrafast through spectral measurements, and that intensity modulation at frequencies in excess of 1 THz can be obtained. By integrating optical polymers through evanescent coupling to silicon waveguides, we greatly increase the effective nonlinearity of the waveguide, allowing operation at continuous wave power levels compatible with telecommunication systems. These devices are a first step in the development of large-scale integrated ultrafast optical logic in silicon, and are two orders of magnitude faster than previously reported silicon devices.

 

Relevant Refereed Papers

  1. "Electro-optic polymer cladding ring resonator modulators", B. A. Block, T. R. Younkin, P. S. Davids, M. R. Reshotko, P. Chang, B. M. Polishak, S. Huang, J. D. Luo and A. K. Y. Jen, Optics Express, 2008, 16(22), 18326-18333
  2. "Microring Resonators Made in Poled and Unpoled Chromophore-Containing Polymers for Optical Communication and Sensors", A. T. Chen, H. S. Sun, A. Pyayt, L. R. Dalton, J. D. Luo and A. K. Y. Jen, Ieee Journal of Selected Topics in Quantum Electronics, 2008, 14(5), 1281-1288
  3. "Highly efficient EO polymers for low V-pi  modulators", D. J. Huang, Danliang; Chen, Baoquan; Chen, Hui; Tolstedt, Don; Condon, Stephen; Barklund, Anna; Yu, Guomin; Miller, Eric; Dinu, Raluca; Luo, Jingdong; Shi, Zhengwei; Kim, Tae-Dong; Huang, Su; Jen, Alex K.-Y, Proceedings of SPIE, 2008, 7049(Linear and Nonlinear Optics of Organic Materials VIII), 70490H/1-70490H/10
  4. "Reinforced Site Isolation Leading to Remarkable Thermal Stability and High Electrooptic Activities in Cross-Linked Nonlinear Optical Dendrimers", Z. W. Shi, J. D. Luo, S. Huang, X. H. Zhou, T. D. Kim, Y. J. Cheng, B. M. Polishak, T. R. Younkin, B. A. Block and A. K. Y. Jen, Chemistry of Materials, 2008, 20(20), 6372-6377
  5. "Electrooptic polymer modulator with single-mode to multimode waveguide transitions", C. T. DeRose, D. Mathine, Y. Enami, R. A. Norwood, J. Luo, A. K. Y. Jen and N. Peyghambarian, Ieee Photonics Technology Letters, 2008, 20(9-12), 1051-1053
  6. "Broadband electro-optic polymer modulators with high electro-optic activity and low poling induced optical loss", H. Chen, B. Chen, D. Huang, D. Jin, J. D. Luo, A. K. Y. Jen and R. Dinu, Applied Physics Letters, 2008, 93(4),
  7. "Donor-acceptor thiolated polyenic chromophores exhibiting large optical nonlinearity and excellent photostability", Y. J. Cheng, J. D. Luo, S. Huang, X. H. Zhou, Z. W. Shi, T. D. Kim, D. H. Bale, S. Takahashi, A. Yick, B. M. Polishak, S. H. Jang, L. R. Dalton, P. J. Reid, W. H. Steier and A. K. Y. Jen, Chemistry of Materials, 2008, 20(15), 5047-5054
  8. "Transversely tapered hybrid electro-optic polymer/sol-gel Mach-Zehnder waveguide modulators", Y. Enami, D. Mathine, C. T. DeRose, R. A. Norwood, J. Luo, A. K. Y. Jen and N. Peyghambarian, Applied Physics Letters, 2008, 92(19),
  9. "Wideband 15 THz response using organic electro-optic polymer emitter-sensor pairs at telecommunication wavelengths", C. V. McLaughlin, L. M. Hayden, B. Polishak, S. Huang, J. D. Luo, T. D. Kim and A. K. Y. Jen, Applied Physics Letters, 2008, 92(15),
  10. "Modeling photobleaching of optical chromophores: Light-intensity effects in precise trimming of integrated polymer devices", G. Gupta, W. H. Steier, Y. Liao, J. D. Luo, L. R. Dalton and A. K. Y. Jen, Journal of Physical Chemistry C, 2008, 112(21), 8051-8060
  11. "Binary chromophore systems in nonlinear optical dendrimers and polymers for large electrooptic activities", T. D. Kim, J. D. Luo, Y. J. Cheng, Z. W. Shi, S. Hau, S. H. Jang, X. H. Zhou, Y. Tian, B. Polishak, S. Huang, H. Ma, L. R. Dalton and A. K. Y. Jen, Journal of Physical Chemistry C, 2008, 112(21), 8091-8098
  12. "Site-isolated electro-optic chromophores based on substituted 2,2 '-bis(3,4-propylenedioxythiophene) pi-conjugated bridges", S. R. Hammond, O. Clot, K. A. Firestone, D. H. Bale, D. Lao, M. Haller, G. D. Phelan, B. Carlson, A. K. Y. Jen, P. J. Reid and L. R. Dalton, Chemistry of Materials, 2008, 20(10), 3425-3434
  13. "Order of magnitude effects of thiazole regioisomerism on the near-IR two-photon cross-sections of dipolar chromophores", K. Schmidt, A. Leclercq, E. Zojer, P. V. Lawson, S. H. Jang, S. Barlow, A. K. Y. Jen, S. R. Marder and J. L. Bredas, Advanced Functional Materials, 2008, 18(5), 794-801
  14. "Guest-host cooperativity in organic materials greatly enhances the nonlinear optical response", Y. V. Pereverzev, K. N. Gunnerson, O. V. Prezhdo, P. A. Sullivan, Y. Liao, B. C. Olbricht, A. J. P. Akelaitis, A. K. Y. Jen and L. R. Dalton, Journal of Physical Chemistry C, 2008, 112(11), 4355-4363
  15. "Mesoscale dynamics and cooperativity of networking dendronized nonlinear optical molecular glasses", T. Gray, T. D. Kim, D. B. Knorr, J. D. Luo, A. K. Y. Jen and R. M. Overney, Nano Letters, 2008, 8(2), 754-759
  16. "Highly efficient diels-alder crosslinkable electro-optic dendrimers for electric-field sensors", Z. Shi, S. Hau, J. Luo, T. D. Kim, N. M. Tucker, J. W. Ka, H. Sun, A. Pyajt, L. Dalton, A. Chen and A. K. Y. Jen, Advanced Functional Materials, 2007, 17(2557-2563
  17. "Phenyltetraene-based nonlinear optical chromophores with enhanced chemical stability and electrooptic activity", J. D. Luo, S. Huang, Y. J. Cheng, T. D. Kim, Z. W. Shi, X. H. Zhou and A. K. Y. Jen, Organic Letters, 2007, 9(4471-4474
  18. "Hybrid cross-linkable polymer/sol-gel waveguide modulators with 0.65 V half wave voltage at 1550 nm", Y. Enami, D. Mathine, C. T. DeRose, R. A. Norwood, J. Luo, A. K. Y. Jen and N. Peyghambarian, Applied Physics Letters, 2007, 91(
  19. "Low half-wave voltage and high electro-optic effect in hybrid polymer/sol-gel waveguide modulators" (vol 89, art. no. 143506, 2006)", Y. Enami, C. T. DeRose, C. Loychik, D. Mathine, R. A. Norwood, J. Luo, A. K. Y. Jen and N. Peyghambarian, Applied Physics Letters, 2007, 91(1),
  20. "Hybrid polymer/sol-gel waveguide modulations with exceptionally large electro-optic coefficients (vol 1, pg 180, 2007)", Y. Enami, C. T. Derose, D. Mathine, C. Loychik, C. Greenlee, R. A. Norwood, T. D. Kim, J. Luo, Y. Tian, A. K. Y. Jen and N. Peyghambarian, Nature Photonics, 2007, 1(7), 423-423
  21. "Efficient acceptor groups for NLO chromophores: competing inductive and resonance contributions in heterocyclic acceptors derived from 2-dicyanomethylidene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran", K. Schmidt, S. Barlow, A. Leclercq, E. Zojer, S. H. Jang, S. R. Marder, A. K. Y. Jen and J. L. Bredas, Journal of Materials Chemistry, 2007, 17(28), 2944-2949
  22. "Metal-slotted polymer optical waveguide device", S. K. Kim, Y. C. Hung, W. Yuan, D. Cha, K. Geary, H. R. Fetterman, S. M. Ha, Q. B. Pei, J. D. Luo, X. H. Zhou, A. K. Y. Jen, M. S. Kwon and W. H. Steier, Applied Physics Letters, 2007, 90(24),
  23. "Theory-guided design and synthesis of multichromophore dendrimers: An analysis of the electro-optic effect", P. A. Sullivan, H. Rommel, Y. Liao, B. C. Olbricht, A. J. P. Akelaitis, K. A. Firestone, J. W. Kang, J. D. Luo, J. A. Davies, D. H. Choi, B. E. Eichinger, P. J. Reid, A. T. Chen, A. K. Y. Jen, B. H. Robinson and L. R. Dalton, Journal of the American Chemical Society, 2007, 129(24), 7523-7530
  24. "All-dielectric electrooptic sensor based on a polymer microresonator coupled side-polished optical fiber", H. S. Sun, A. Pyajt, J. D. Luo, Z. W. Shi, S. Hau, A. K. Y. Jen, L. R. Dalton and A. T. Chen, Ieee Sensors Journal, 2007, 7(3-4), 515-524
  25. "Molecular mobility and transitions in complex organic systems studied by shear force microscopy", T. Gray, J. Killgore, J. D. Luo, A. K. Y. Jen and R. M. Overney, Nanotechnology, 2007, 18(4),
  26. "Improvement of electro-optic effect and novel waveguide structure in hybrid polymer/sol-gel modulators", Y. D. Enami, C. T.; Loychik, C. L.; Mathine, D. L.; Norwood, R. A.; Luo, J.; Jen, A. K.-Y.; Peyghambarian, N., Proceedings of SPIE-The International Society for Optical Engineering, 2007, 6470(Organic Photonic Materials and Devices IX), 64700G/1-64700G/8
  27. "Electrooptic polymer ring resonator modulation up to 165 GHz", B. Bortnik, Y. C. Hung, H. Tazawa, B. J. Seo, J. D. Luo, A. K. Y. Jen, W. H. Steier and H. R. Fetterman, Ieee Journal of Selected Topics in Quantum Electronics, 2007, 13(1), 104-110
  28. "Large electro-optic activity and enhanced thermal stability from diarylaminophenyl-containing high-beta nonlinear optical chromophores", Y. J. Cheng, J. D. Luo, S. Hau, D. H. Bale, T. D. Kim, Z. W. Shi, D. B. Lao, N. M. Tucker, Y. Q. Tian, L. R. Dalton, P. J. Reid and A. K. Y. Jen, Chemistry of Materials, 2007, 19(5), 1154-1163
  29. "Two-photon absorption in quadrupolar bis(acceptor)-terminated chromophores with electron-rich bis(heterocycle)vinylene bridges", S. J. Zheng, A. Leclercq, J. Fu, L. Beverina, L. A. Padilha, E. Zojer, K. Schmidt, S. Barlow, J. D. Luo, S. H. Jiang, A. K. Y. Jen, Y. P. Yi, Z. G. Shuai, E. W. Van Stryland, D. J. Hagan, J. L. Bredas and S. R. Marder, Chemistry of Materials, 2007, 19(3), 432-442
  30. "Ultralarge and thermally stable electro-optic activities from supramolecular self-assembled molecular glasses", T. D. Kim, J. W. Kang, J. D. Luo, S. H. Jang, J. W. Ka, N. Tucker, J. B. Benedict, L. R. Dalton, T. Gray, R. M. Overney, D. H. Park, W. N. Herman and A. K. Y. Jen, Journal of the American Chemical Society, 2007, 129(488-489
  31. "Nanostructured functional block copolymers for electrooptic devices", Y. Q. Tian, C. Y. Chen, M. A. Haller, N. M. Tucker, J. W. Ka, J. D. Luo, S. Huang and A. K. Y. Jen, Macromolecules, 2007, 40(1), 97-104
  32. Terahertz All-Optical Modulator in Silicon”, M. Hochberg, T. Bachr-Jones, G. Wang, J. Parker, K. Harvard, J. D. Luo, B. Chen, Z. Shi, R. Lawson, P. Sullivan, A. K-Y. Jen, L. Dalton, and A. Scherer, Nature Materials, 2006, 5(9) , 703.
  33. “Pockel’s Coefficient Enhancement of Poled Electro-optic Polymers with a Hybrid Organic-Inorganic Sol-gel Cladding Layer”, C. T. DeRose, Y. Enami, C. Lychok, R. A. Norwood, D. Methine, M. Fallahi, N. Peyghambarian, J. D. Luo, A. K-Y. Jen, M. Kathaperumal, M. Yamamoto, Appl. Phys. Lett., 2006, 89(13), 131102.
  34. “Ultra-Large and Thermally Stable Electro-Optic Activities from Diels-Alder Crosslinkable Polymers Containing Binary Chromophore Systems”, T. D. Kim, J. Luo, J-W. Ka, S. Hau, Y. Tian, Z. Shi, N. M. Tucker, S.-H. Jang, J.-W. Kang, and A. K-Y. Jen, Adv. Mater., (in press).
  35. “Recent Advances in Organic Nonlinear Optics”, N. Peyghambarian, L. Dalton, A. K-Y. Jen, B. Kippelen, J. Perry, and S. Marder, Laser Focus World, 2006, 42(8), 85.
  36. “ Low Half-wave Voltage and High Electro-optic Effect in Hybrid Polymer/Sol-gel Waveguide Modulators”, Y. Enami1, C.T. DeRose, C. Loychik, D. Mathine, R. A. Norwood, J. Luo, and A. K-Y. Jen, and N. Peyghambarian , Appl. Phys. Lett., 2006 , 89(14), 143506.
  37. “Ring Resonator-Based Electro-optic Polymer Traveling-Wave Modulator”, H. Tazawa, Y. H. Kuo, I. Dunayevskiy, J. Luo, A. K-Y. Jen, H. Fetterman, and W. H. Steier, J. Lightwave Tech., 2006, 24(9), 3514.
  38. “Micro Resonators on Side-polished Fiber – A Potential Fiber Optic Sensor Platform”, A. Chen, A. C. Young, J. D. Luo, Z. W. Shi, S. Hau, A. K-Y. Jen, H. Sun, A. Pyayt, J. Takayesu, and L. R. Dalton, IEEE Sensor (in press).
  39. “Photobleaching Fabrication of Microring Resonator in a Chromophore Containing Polymer”, J. Zhou, A. Pyayt, L. Dalton, J. Luo, A. K-Y. Jen, and A. Chen, IEEE Photon. Technol. Lett., (in press).
  40. “ Third Order Nonlinearity Contribution to Electro-optic Activity in Polymer Materials under a Constant DC Bias Field”, N. P. Bhatambrekar, L. R. Dalton, J. D. Luo, A. K-Y. Jen, and A. Chen, Appl. Phys. Lett., 2006, 88, 041115.
  41. “Low Drive Voltage Fabry-Perot Etalon Device Tunable Filters using Electro-optic Hybrid Sol-gel Materials”, H. Gan, H. Zhang, C. T. DeRose, R. A. Norwood, N. Peyghambarian, M. Fallahi, J. D. Luo, B. Chen, A. K-Y. Jen, Appl. Phys. Lett., 2006, 89, 041127.
  42. “Linear and Nonlinear Optical Properties of a Macrocyclic Trichromophore Bundle with Parallel-Aligned Dipole Moments”, Y. Liao, K. A. Firestone, S. Bhattacharjee, J. D. Luo, M. Haller, S. Hau, C. A. Anderson, D. Lao, B. E. Eichinger, B. H. Robinson, P. J. Reid, A. K-Y. Jen, L. R. Dalton, J. Phys. Chem. B, 2006, 110(11), 5434.
  43. “Pyrroline Chromophores for Electro-Optics”, S. H. Jang, J. D. Luo, N. M. Tucker, A. Leclercq, E. Zojer, M. A. Haller, T. D. Kim, J. W. Kang, K. Firestone, D. Bale, D. Lao, J. B. Benedict, D. Cohen, W. Kaminsky, B. Kahr, J-L. Brédas, P. Reid, L. R. Dalton, and A. K.-Y. Jen, Chem. Mater., 2006, 18(13), 2982.
  44. “Facile Synthesis of Highly Efficient Phenyltetraene-Based Nonlinear Optical Chromophores for Electro-Optics”, J. D. Luo, Y.-J. Cheng, T.-D. Kim, S. Hau, S. H. Jang, Z. Shi, and A. K-Y. Jen, Org. Lett., 2006, 8(7), 1387.
  45. “High Speed AJL8/APC Polymer Modulator”, R. J. Michalak, Y-H. Kuo, F. Nash, A. Szep, J. Caffey, P. Payson, F. Haas, B. McKeon, P. Cook, G. Brost, J. D. Luo, A. K-Y Jen, L. R. Dalton, and W. H. Steier, IEEE Photon. Technol. Lett. ,2006, 18(11), 1207.
  46. “Quantum-Chemical Investigation of Second-Order Nonlinear Optical Chromophores: Comparison of Strong Nitrile-based Acceptor End Groups and Role of Auxiliary Donors and Acceptors”, A. Leclercq, E. Zojer, S.-H. Jang, S. Barlow, V. Geskin, A. K.-Y. Jen, S. R. Marder, and J. L. Brédas, J. Chem. Phys.,2006, 124, 044510
  47. “Interfacial Shear Strength of the Perfluorocyclobutane (PFCB) Films on Silicon”, S. R. Boddapati, H. Ma, R. K. Bordia, and A. K-Y. Jen, J. Mater. Res.2006, 21(7), 1759.
  48. “Diels-Alder “Click” Chemistry for Highly Efficient Electro-optic Polymers”, T. D. Kim, J. Luo, M. Haller, J. W. Kang, Y. Tian, and A. K-Y. Jen, Macromolecules,2006, 39, 1676.
  49. “Enhanced Thermal Stability of Electro-optic Polymer Modulator Using Diels-Alder Crosslinking Polymer”, Y. H. Kuo, J. D. Luo, W. H. Steier, and A. K-Y. Jen, IEEE Photon. Technol. Lett. , 2006, 18(1), 175.
  50. “Low Temperature Relaxations and Effects on Poling Efficiencies of Dendronized Non-linear Optical Side-Chain Polymers”, T. Gray, R. Overney, M. Haller, J. D. Luo, and A. K-Y. Jen, Appl. Phys. Lett., 2005, 86, 211908.
  51. “Organic Electro-optic Modulator Using Transparent Conducting Oxide as Electrode”, G. Xu, Z. Liu, J. Ma, B. Liu, S-T. Ho, L. Wang, P. Zhu, T. J. Marks, J. D. Luo, and A. K-Y. Jen, Optical Express, 2005, 13(19), 7380.
  52. “Micro-ring Resonators on Side-polished Optical Fibers”, T. Sherwood, A. C. Young, J. Takayesu, A. K.Y. Jen, L. R. Dalton, and A. Chen, IEEE Photon. Technol. Lett. , 2005, 17(10), 2107.
  53. “Electro-optic Properties of Hybrid Sol-gel Doped with a High Nonlinear Hyperpolarizability Chromophore”, H. X. Zhang, D. Lu, N. Peyghambarian, M. Fallahi, J. D. Luo, B. Chen, and A. K-Y. Jen, Optics Lett., 2005, 30(2), 1.
  54. “Systematic Study of the Structure-Property Relationship of a Series of Ferrocenyl Nonlinear Optical Chromophores”, Y. Liao, B. E. Eichinger, K. A. Firestone, M. Haller, J. Luo, W. Kaminsky, J. B. Benedict, P. J. Reid, A. K-Y Jen, L. R. Dalton, and B. H. Robinson , J. Am. Chem. Soc., 2005, 127, 2758.
  55. “Very large electro-optic coefficients from chrom ophore doped side-chain polymers”, J. W. Kang, T. D. Kim, J. D. Luo, M. Haller, and A. K-Y. Jen, Appl. Phys. Lett., 2005, 87, 071109.
  56. “Light Detection and Electro-optic Tuning in Slotted Waveguides”, T Baehr-Jones, M. Hochberg, G. Wang, R. Lawson, Y. Liao, P. A Sullivan, C. Walker, L. Dalton, A. K.-Y. Jen, A. Scherer, Optical Express, 2005, 13, 5216.
  57. “High Fluorinated and Crosslinkable Dendritic Polymer for Photonic Applications”, H. Ma, J. Luo, S. Wong, A. K-Y. Jen, R. Barto, C. Frank, Macromol. Rapid Commun., 2004, 25, 1667.
  58. “A Side-Chain Dendronized Nonlinear Optical Polyimide with Large and Thermally Stable Electro-Optic Activity”, J. Luo, M. Haller, H. Li, H. Z. Tang, A. K-Y. Jen, K. Jakka, C-H. Chou, and C-F. Shu, Macromolecules, 2004, 37, 248.
  59. “A Smartly Controlled Lattice Hardening Process to Achieve Highly Efficient and Thermally Stable Crosslinked Nonlinear Optical Polymers”, M. Haller, J. Luo, H. Li, T. Kim, Y. Liao, H. Ma, L. R. Dalton, and A. K-Y. Jen, Macromolecules, 2004, 37(3), 688.
  60. “Nanoscale Architectural Control and Macromolecular Engineering of Nonlinear Optical Dendrimers and Polymers for Electro-Optics”, J. Luo, M. Haller, H. Ma, S. Liu, T. D. Kim, Y. Tian, S. H. Jang, B. Chen, L. R. Dalton, and A. K-Y. Jen, J. Phys. Chem. B., 2004, 108(25), 8523.
  61. “One, Two, and Three-Photon Absorption Induced Fluorescence of a New Chromophore in Chloroform Solution”, Y. Wang, O. Y-H. Tsai, C. H. Wang, and A. K-Y. Jen, J. Chem. Phys., 2004, 121(16), 7901.
  62. “Wavelength Dependence of First Molecular Hyperpolarizability of a Dendrimer in Solution”, O. Y-H. Tsai, C. H. Wang, H. Ma, and A. K-Y. Jen, J. Chem. Phys., 2004, 121(12), 6086.
  63. “Resonance Enhanced THz Generation in Electro-optic Polymers Near the Absorption Maximum”, A. M. Sinyukov, M. R. Leahy, and L. M. Hayden, M. Haller, J. Luo, A. K-Y. Jen, and L. R. Dalton, Appl. Phys. Lett., 2004, 85(24), 5827.
  64. “Perfluorocyclobutane-based Polyester (arlene ether)s for Applications in Integrated Optics”, S. Wong, H. Ma, A. K-Y. Jen, R. Barto, and C. Frank, Macromolecules, 2004, 37, 5578
  65. “Trends in Optical Nonlinearity and Thermal Stability in Electro-optic Chromophores Based upon the 3-(Dicyanomethylene)-2,3-dihydrobenzothiophene-1,1-dioxide Acceptor”, Z. Hu, A. Fort, M. Barzoukas, A. K.-Y. Jen, S. Barlow, and S. R. Marder, J. Phys. Chem. B., 2004, 108 (25), 8626.
  66. “Replica Molded Electro-Optic Mach-Zhender Modulator”, G. Paloczi, Y. Huang, A. Yariv, J. Luo, and A. K-Y. Jen, Appl. Phys. Lett.,2004, 85(10), 1662.
  67. “Hyper-Rayleigh Scattering and Frequency Dependence of the Molecular Hyperpolarizability of a Strong Charge-Transfer Chromophore”, C. H. Wang, Y. C. Lin, O. Y. Tai, A. K-Y. Jen, and A. M. Kelley, J. Chem. Phys., 2003 , 119(12), 6237.
  68. “Highly Fluorinated Trifluorovinyl Aryl Ether Monomers and Perfluorocyclobutane (PFCB) Aromatic Ether Polymers for Optical Waveguide Applications”, S. Wong, H. Ma, and A. K.-Y. Jen, R. Barto, and C. Frank, Macromolecules, 2003, 36, 8001.
  69. “Highly Efficient and Thermally Stable Electro-optic Polymer from a Smartly Controlled Poling and Crosslinking Process”, J. Luo, M. Haller, H. Li, and A. K-Y. Jen, Adv. Mater., 2003, 15(19), 1635.
  70. “Hyperbranched Fluorinated Aromatic Polyester from Mild One-Pot Polymerization of AB 2 Hydroxy Acid Monomer”, S. Kang, J. Luo, H. Ma, L. R. Dalton, and A. K-Y. Jen, Macromolecules, 2003, 36, 4355.
  71. “Polymeric Materials and Their Orientation Techniques for Second-Order Nonlinear Optics”, F. Kajzar, K. S. Lee and A. K-Y. Jen, Special Issue for Polymers for Photonic Applications”, Invited Review, Adv. Polym Sci., 2003, 161, 1.
  72. “Systematic Development of High Bandwidth, Low Drive Voltage Organic Electro-Optic Devices and Their Applications,” L. R. Dalton, B. H. Robinson, A. K. Y. Jen, and W. H. Steier Opt. Mater., 2003, 21, 19.
  73. “Polarization Insensitive Transition between Sol-gel Waveguide and Electro-optic Polymer and Intensity Modulation for All-optical Networks”, Y. Enami, M. Kawaz, A. K-Y. Jen, G. Meredith, N. Peyghambarian, J. Lightwave Tech., 2003, 21(9), 2053.
  74. “Hybrid Electro-optic Polymer/Sol-Gel Waveguide Modulator Fabricated by All-Wet Etching Process”, Y. Enami, G. Meredith, A. K-Y. Jen, and N. Peyghambarian, Appl. Phys. Lett., 2003, 83(23), 4692.
  75. “Hybrid Electro-optic Polymer/Selective Buried Sol-gel Waveguides for the Integration of Phase-Modulator at 1.55 mm”, Y. Enami, N. Peyghambarian, M. Kawazu, and A. K-Y. Jen, Appl. Phys. Lett.,2003, 82(4), 490.
  76. “Nanostructured Functional Dendrimers and Polymers for Photonics”, J. Luo, H. Ma, and A. K-Y. Jen, invited review for a book-like Comptes Rendus issue on "Dendrimers and Nanosciences, 2003, 8(10), 793.
  77. “Focused Microwave-Assisted Synthesis of Highly Efficient Nonlinear Optical Chromophores and Their Performance in Electro-Optics”, S. Liu, M. Haller, H. Ma, L. R. Dalton, and A. K-Y. Jen, Adv. Mater., 2003, 15(7-8), 603.
  78. “Highly Efficient and Thermally Stable Electro-Optic Dendrimers for Photonics”, H. Ma, S. Liu, J. Luo, S. Suresh, L. Liu, S. H. Kang, M. Haller, Takafumi Sassa, and Alex K.-Y. Jen, Adv. Func. Mater., 2002, 12, 565.
  79. “A Fluorinated Dendritic Nonlinear Optical Chromophore with Improved Comprehensive Properties for Electro-Optics”, J. Luo, H. Ma, M. Haller, A. K.-Y. Jen and R. R. Barto, Chem. Commun., 2002, 8, 888.
  80. “Design, Synthesis, and Properties of Highly Efficient Side-chain Dendronized Nonlinear Optical Polymers for Electro-optics”, J. Luo, S. Liu, M. Haller, L. Liu, H. Ma, Alex K-Y. Jen, Adv. Mater., 2002, 14(23), 1763.
  81. “Polymer-Based Optical Waveguides: Materials, Process, and Devices”, H. Ma, A. K-Y. Jen, and L. R. Dalton, Adv. Mater., 2002, 14(19), 1339.