Low (Sub-1-volt) halfwave voltage polymeric electro-optic modulators achieved by controlling chromophore shape

Synthesis and characterization of a novel second-order nonlinear optical chromophore based on a new julolidine donor

A new chromophore was synthesized and the hyperpolarizability can be effectively translated into large electro-optic coefficients in poled polymers.

Comparison of nonlinear optical chromophores containing different conjugated electron-bridges: the relationship between molecular structure-properties and macroscopic electro-optic activities of materials

In electro-optic (EO) materials, realization of large EO coefficients for organic EO materials requires the simultaneous optimization of chromophore first hyperpolarizability, acentric order, molecular shape etc.

Low-loss sharp bends in polymer waveguides enabled by the introduction of a thin metal layer

Embodying a thin metallic layer underneath the core of a sharply bent polymer waveguide is shown in this work to considerably reduce the total losses of both the quasi-transverse-electric and quasi-transverse-magnetic modes. The computational results show a total loss as low as ~0.02 dB/90° for the quasi-transverse-electric mode for radii between 6 and 13 µm at the wavelength of 1.55 µm, which corresponds to a 10-fold improvement over the purely dielectric counterpart. The radii range exhibiting such low total loss can be tuned by properly selecting the parameters of the structure. For the quasi-transverse-magnetic mode, the metal layer reduces the total losses modestly for radii ranging from 3 to 10 µm. Simulation results for different structural parameters are presented.

Wide optical spectrum range, subvolt, compact modulator based on an electro-optic polymer refilled silicon slot photonic crystal waveguide

We design and demonstrate a compact and low-power, band-engineered, electro-optic (EO) polymer refilled silicon slot photonic crystal waveguide (PCW) modulator. The EO polymer is engineered for large EO activity and near-infrared transparency. A PCW step coupler is used for optimum coupling to the slow-light mode of the band-engineered PCW. The half-wave switching voltage is measured to be Vπ = 0.97 ± 0.02 V over an optical spectrum range of 8 nm, corresponding to the effective in-device r(33) of 1199 pm/V and V(π) × L = 0.291 ± 0.006 V × mm in a push-pull configuration. Excluding the slow-light effect, we estimate that the EO polymer is poled with an efficiency of 89 pm/V in the slot.

Giant electro-optic effect in nanodisordered KTN crystals

The electro-optic (EO) effect in nanodisordered potassium tantalate niobate (KTN) crystal is quantitatively investigated. It is found out that the EO coefficient of nanodisordered KTN crystal depends not only on the cooling temperature but also on the cooling rate. A larger EO coefficient can be obtained by employing a faster cooling rate. A Kerr EO efficient (s(11) - s(12) = 6.94 × 10(-14) m(2)/V(2)) is obtained at a cooling rate of 0.45 °C/s. The enhanced EO efficient by employing a faster cooling rate will be greatly beneficial for a variety of applications such as laser Q switches, laser pulse shaping, high-speed optical shutters, and modulating retroreflectors.

Dendrimers with large nonlinear optical performance by introducing isolation chromophore, utilizing the Ar/ArF self-assembly effect, and modifying the topological structure

By the combination of divergent and convergent approach, a new series of NLO dendrimers (G1-PFPh-NS-GL to G3-PFPh-NS-GL) was conveniently prepared with satisfied yields through the powerful "click chemistry" reaction, in which perfluoroaromatic rings were introduced in the periphery, two types of chromophores were arranged with regular AB structure, and their topological structure was improved to a more spherical shape. All the dendrimers demonstrated good processability, and G1-PFPh-NS-GL exhibited the highest NLO effect of 221 pm/V among the three dendrimers.

Solid-state reversible quadratic nonlinear optical molecular switch with an exceptionally large contrast

Exceptional nonlinear optical (NLO) switching behavior, including an extremely large contrast (on/off) of ∼35 and high NLO coefficients, is displayed by a solid-state reversible quadratic NLO switch. The favorable results, induced by very fast molecular motion and anionic ordering, provides impetus for the design of a novel second-harmonic-generation switch involving molecular motion.

From nitro- to sulfonyl-based chromophores: improvement of the comprehensive performance of nonlinear optical dendrimers

Through the combination of the divergent and convergent approaches, coupled with the utilization of the powerful Sharpless "click-chemistry" reaction, two series of sulfonyl-based high-generation NLO dendrimers were conveniently prepared with high purity and in satisfactory yields. Thanks to the perfect three-dimensional (3D) spatial isolation from the highly branched structure and the isolation effect of the exterior benzene moieties and the interior triazole rings, these dendrimers exhibited large second harmonic generation coefficient (d33) values up to 181 pm V(-1), which, to the best of our knowledge, is the highest value so far for polymers containing sulfonyl-based chromophore moieties. Meanwhile, compared with the nitro-chromophore-based analogues, their optical transparency and NLO stability were improved in a large degree, due to the lower dipole moment (μ) and the special main-chain structure of sulfonyl-based chromophore in these dendrimers.

Full spectrum millimeter-wave modulation

In recent years, the development of new lithium niobate electro-optic modulator designs and material processing techniques have contributed to support the increasing need for faster optical networks by considerably extending the operational bandwidth of modulators. In an effort to provide higher bandwidths for future generations of networks, we have developed a lithium niobate electro-optic phase modulator based on a coplanar waveguide ridged structure that operates up to 300 GHz. By thinning the lithium niobate substrate down to less than 39 µm, we are able to eliminate substrate modes and observe optical sidebands over the full millimeter-wave spectrum.

DFT STUDIES ON ELECTRONIC STRUCTURES AND THIRD-ORDER NONLINEAR OPTICAL PROPERTIES OF A SERIES OF Pt–Pt BOND-CONTAINING METAL COMPLEXES

In this paper, electronic structures and third-order nonlinear optical (NLO) properties of a series of Pt–Pt bond-containing metal complexes have been calculated by using the density functional theory (DFT) combining with the sum-over-states (SOS) method. In order to check the reliability of this method, the electron correlations and basis sets have been compared. Our calculated results show that introduction of electron donor, thiophene ring and lengthing of organic conjugated ligand can enhance third-order NLO responses. The electronic structure analysis shows that the [Pt–Pt(H2P(CH2)PH2)2] fragment displays strong electron-withdrawing character in these systems. Meanwhile, the third-order NLO response of Pt–Pt bond also has been estimated by using TDDFT–SOS method. An enhancement of third-order NLO response has been observed because of the introduction of the Pt–Pt bond. This is mainly due to the intense and low-lying metal-to-ligand charge transfer (MLCT) and intraligand (IL) CT transitions.

New hyperbranched polytriazoles containing isolation chromophore moieties derived from AB4 monomers through click chemistry under copper(I) catalysis: improved optical transparency and enhanced NLO effects

By modifying a synthetic procedure, two new hyperbranched polytriazoles (HP1 and HP2) containing isolation chromophores were synthesized successfully through click chemistry reactions under copper(I) catalysis. For the first time, these two polymers were derived from an AB(4)-type monomer, although they contain different end-capping chromophores. They are soluble in normal polar organic solvents and are well characterized. Thanks to the presence of the isolation chromophore, the two polymers demonstrate good nonlinear optical (NLO) properties and optical transparency, making them promising candidates for practical applications.