John S. Zetts

Effect of conductivity and dielectric constant on the modulation voltage for optoelectronic devices based on nonlinear optical polymers

Presented is the effect of using various cladding materials with different conductivities and dielectric constants on the applied voltage for optoelectronic (OE) devices based on nonlinear optical (NLO) polymers. Using a conductive polymer, we have demonstrated a 3 to 13 times increase in the effective electro-optic (EO) coefficient of electrode- poled NLO polymers, compared to using passive polymer claddings. We have achieved the lowest poling voltage to date for maximum EO coefficient, 300 V, for a two-layer waveguide structure consisting of a 2-?m- thick NLO polymer layer and a 2-?m-thick conductive cladding layer. The dielectric constants of both the NLO polymer core and passive polymer cladding materials used for conventional polymer-based integrated optic devices are typically very similar in magnitude. This suggests that only a small fraction of the applied modulation voltage is reaching the NLO polymer core layer, requiring 4 to 5 times higher modulation voltage than the desired V?. We have demonstrated a factor-of-2 decrease in the modulation voltage using the same conductive polymer, due to its possessing a much higher dielectric constant than the core material at the modulation frequency tested. The results show promise for shorter, lower-operating-voltage devices.

DNA Photonics [Deoxyribonucleic Acid]

ABSTRACT Purified deoxyribonucleic acid (DNA) derived from salmon and scallop sperm has demonstrated excellent passive and active optical properties. Characterization of the optical and electromagnetic properties of DNA suggests suitability for photonic applications. One of interesting features of DNA we discovered was an intercalation of aromatic compounds into stacked layers within the double helix of DNA molecules. We found that various optical dyes inserted into the double helix of DNA molecules rendered active optical waveguide materials with excellent nonlinear optical properties. Our research included the investigation of DNA for use as an optical waveguide material as well as intercalation of fluorescent dyes, photochromic dyes, nonlinear optic chromophores, two photon dyes and rare earth compounds into DNA for use as a nonlinear optical material.

Enhanced electro-optic poling in guest–host systems using conductive polymer-based cladding layers

We report on the development of conductive polymer-based cladding layers for use in multilayered electro-optic (EO) device structures. The waveguide claddings used in these studies were based on blends formed from the conductive polymer poly (ethylene dioxythiophene) with poly (vinylalcohol). Thin films of the blended materials were spun to form cladding layers having tunable conductivity and optical absorption. We tested these materials using a well-known guest–host core layer to determine their effect on the polar alignment of second order nonlinear optical chromophores. The claddings tested were shown to provide a large effective poling field across the active layer, and thus produced larger EO coefficients than systems having comparable, but more highly resistive, claddings.

DNA- new class of polymer

Suitable organic and polymeric based materials for electronic and photonic applications must possess the desired electromagnetic and optical properties to achieve optimal device performance in order to be more competitive with their inorganic counterparts. A new class of biopolymer, processed from purified marine-based deoxyribonucleic acid (DNA), has been investigated for use in both electronic and photonic applications and has demonstrated promise as an excellent dielectric and optical waveguide material. In this paper we present examples of devices using this new DNA-based biopolymer.

In-situ high-energy proton irradiation of nonlinear organic modulator materials for space environments

The behavior of two nonlinear polymer-modulator materials irradiated by 63.3 MeV protons to a dose of 1 Mrad(Si) is reported. The effects of proton induced ionization and heating in disperse red 1/poly(methylmethacrylate) and in poly(ethylene dioxythiophene)/poly styrene sulphonate/poly(vinyl alcohol) thin films are discussed. Attenuation of the light transmission at an optical wavelength of (lambda) equals 0.6328 micrometers was measured in the polymer films, conductive coatings and their respective substrates. Comparison of these results with a recently reported study of related nonlinear polymer modulator materials exposed to protons is discussed. Conclusions and recommendations regarding the potential application of polymers in the near-Earth space environment are presented.

DNA-based materials for electro-optic applications : current status

Purified deoxyribonucleic acid (DNA), derived from salmon milt and roe sacs, waste products of the Japanese fishing industry in Hokkaido, has been processed into a promising, optical waveguide quality, biopolymer material suitable for both passive and active optical and electro-optic applications. Intercalation of aromatic compounds into stacked layers within the double helix of DNA molecules has rendered active optical waveguide materials with excellent nonlinear optical properties.

Deoxyribonucleic acid (DNA)-based nonlinear optics

Highly purified deoxyribonucleic acid (DNA) was isolated from salmon and scallop sperm by an enzymatic isolation process. Characterization of the optical and electromagnetic properties of DNA suggested suitability for optical waveguide applications. One of the characteristic features of DNA we discovered was an intercalation of aromatic compounds into stacked layers within the double helix of DNA molecules. We found that various optical dyes inserted into the double helix of DNA molecules render optical waveguide films of dye-intercalated DNA suitable for active photonic devices. Our investigation includes intercalation of fluorescent dyes, photochromic dyes, nonlinear optic chromophores, two photon dyes and rare earth compounds into DNA comparing results with poly(methyl methacrylate) (PMMA) based materials.

Conductive cladding layers for electrode-poled nonlinear optic polymer electro-optics

We have demonstrated an enhancement in the effective electro-optic (EO) coefficient of electrode poled nonlinear optical polymers using a conductive polymer cladding. We have also demonstrated the lowest poling voltage to date, 300 V, for a 2 micrometers thick NLO polymer core and 2 micrometers thick conductive polymer cladding structure asymmetric waveguide structure. With the cladding material more conductive than the core material, the majority of the applied poling voltage is dropped across the core, maximizing poling efficiency and, hence, realizing a higher EO coefficient. These results show promise for lower operating voltage devices.

Behavior of NLO polymer modulators irradiated by gamma rays

Two second-order nonlinear optical chromophoric materials were investigated for their response to gamma-ray irradiations for doses ranging from approximately 10-104 krad(Si). Thin film polymer modulators composed of a mixture of amorphous polycarbonate and phenyltetraene [APC/CLD-1(CPW-1)] active regions with UV upper and lower UV claddings were investigated for their pre- and post-irradiation behavior. Modulator Vπ insertion loss, and extinction ratio responses were examined, while a blend of salmon deoxyribonucleic acid (DNA)- hexadeCetylTriMethylAmmonium Chloride (CTMA) film samples were studied for their spectral response following irradiations over the spectral range λ=240-2600 nm. Following irradiation ranging from 9.6-104 krad(Si), the DNA/CTMA films exhibited losses in transmissivity over the spectral range λ=882-2600 nm and increased transmissivity over portions of the 240 nm < λ < 882 nm band. Data from the study also suggested that strongly poled APC/CPW-1 modulators operating at λ=1550 nm and exhibiting low Vπ values were less likely to have their half-wave voltages affected by ionizing radiation. The optical insertion losses for the majority of the APC/CPW-1 irradiated mdolators were found to decrease following irradiation. Discussion of the experimental results and mechanisms believed responsible for the post-irradiation behavior and results are presented.

Deoxyribonucleic acid (DNA)-based optical materials

Optical materials for waveguiding applications must possess the desired optical and electromagnetic properties for optimal device performance. Purified deoxyribonucleic acid (DNA), derived from salmon sperm, has been investigated for use as an optical waveguide material. In this paper we present the materials processing and optical and electromagnetic characterization of this purified DNA to render a high quality, low loss optical waveguide material.