327 research outputs found

    Replica-molded electro-optic polymer Mach–Zehnder modulator

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    A Mach-Zehnder electro-optic polymer amplitude modulator is fabricated by a simple and high-throughput soft-stamp replica-molding technique. The modulator structure incorporates the highly nonlinear and stable chromophore, AJL8, doped in amorphous polycarbonate. Single-arm phase-retardation results in a halfwave voltage (V-pi) of 8.4 V at 1600 nm. The on/off extinction ratio is better than 19 dB, resulting from precise Y-branch power splitters and good waveguide uniformity. These results indicate that the simple fabrication process allows for good optical performance from high-fidelity replicas of the original master devices

    Short hybrid polymer/sol-gel silica waveguide switches with high in-device electro-optic coefficient based on photostable chromophore

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    The highest electro-optic (EO) coefficient to date is achieved in short polymeric directional coupler switches based on hybrid EO polymer/sol-gel silica waveguides. Optimized poling conditions in such waveguides give a highest in-device EO coefficient of 160 pm/V at 1550 nm using highly efficient and photostable guest–host EO polymer SEO100. Adiabatic waveguide transitions from the passive sol-gel core to active EO polymer cores surrounding the sol-gel core are shown using EO polymer cores with a coplanar tapered structure. Switching voltages of 8.4 and 10.5 V are achieved for electrodes that are 2.1 and 1.5 mm long, respectively, which are half those of EO switches containing the chromophore AJLS102

    Threshold voltage control in organic thin film transistors with dielectric layer modified by a genetically engineered polypeptide

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    This is the published version. Copyright 2010 American Institute of PhysicsPrecise control over the threshold voltage of pentacene-based organic thin film transistors was achieved by inserting a genetically engineered quartz-binding polypeptide at the semiconductor-dielectric interface. A 30 V range was accessed with the same peptide by adjusting the pH of the solution for peptide assembly while leaving other device properties unaffected. Mobility of 0.1–0.2 cm2 V−1 s−1 and on/off current ratio of >106 could be achieved for all devices regardless of the presence of the neutral peptide or the peptide assembled in acidic or basic conditions. This shift in threshold voltages is explained by the generation of charged species and dipoles due to variation in assembling conditions. Controlling device characteristics such as threshold voltage is essential for integration of transistors into electronic circuits

    Broadband energy-efficient optical modulation by hybrid integration of silicon nanophotonics and organic electro-optic polymer

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    Silicon-organic hybrid integrated devices have emerging applications ranging from high-speed optical interconnects to photonic electromagnetic-field sensors. Silicon slot photonic crystal waveguides (PCWs) filled with electro-optic (EO) polymers combine the slow-light effect in PCWs with the high polarizability of EO polymers, which promises the realization of high-performance optical modulators. In this paper, a broadband, power-efficient, low-dispersion, and compact optical modulator based on an EO polymer filled silicon slot PCW is presented. A small voltage-length product of V{\pi}*L=0.282Vmm is achieved, corresponding to an unprecedented record-high effective in-device EO coefficient (r33) of 1230pm/V. Assisted by a backside gate voltage, the modulation response up to 50GHz is observed, with a 3-dB bandwidth of 15GHz, and the estimated energy consumption is 94.4fJ/bit at 10Gbit/s. Furthermore, lattice-shifted PCWs are utilized to enhance the optical bandwidth by a factor of ~10X over other modulators based on non-band-engineered PCWs and ring-resonators.Comment: 12 pages, 4 figures, SPIE Photonics West Conference 201

    Trends in Optical Nonlinearity and Thermal Stability in Electrooptic Chromophores Based upon the 3-(Dicyanomethylene)-2,3-dihydrobenzothiophene-1, 1-dioxide Acceptor

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    A series of new thiophene-bridged chromophores based on the powerful heterocyclic acceptor 3-(dicyanomethylene)-2,3-dihydrobenzothiophene-1,1-dioxide has been synthesized; the dependence of the linear and second-order nonlinear optical properties and thermal stability of these species upon the donor group and the bridging group have been studied. In addition, the synthesis of a related new acceptor, not containing the fused benzene ring, is described and a chromophore based upon this acceptor is studied

    Silicon-Organic Hybrid (SOH) Mach-Zehnder Modulators for 100 Gbit/s On-Off Keying

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    Electro-optic modulators for high-speed on-off keying (OOK) are key components of short- and mediumreach interconnects in data-center networks. Besides small footprint and cost-efficient large-scale production, small drive voltages and ultra-low power consumption are of paramount importance for such devices. Here we demonstrate that the concept of silicon-organic hybrid (SOH) integration is perfectly suited for meeting these challenges. The approach combines the unique processing advantages of large-scale silicon photonics with unrivalled electro-optic (EO) coefficients obtained by molecular engineering of organic materials. In our proof-of-concept experiments, we demonstrate generation and transmission of OOK signals with line rates of up to 100 Gbit/s using a 1.1 mm-long SOH Mach-Zehnder modulator (MZM) which features a {\pi}-voltage of only 0.9 V. This experiment represents not only the first demonstration of 100 Gbit/s OOK on the silicon photonic platform, but also leads to the lowest drive voltage and energy consumption ever demonstrated at this data rate for a semiconductor-based device. We support our experimental results by a theoretical analysis and show that the nonlinear transfer characteristic of the MZM can be exploited to overcome bandwidth limitations of the modulator and of the electric driver circuitry. The devices are fabricated in a commercial silicon photonics line and can hence be combined with the full portfolio of standard silicon photonic devices. We expect that high-speed power-efficient SOH modulators may have transformative impact on short-reach optical networks, enabling compact transceivers with unprecedented energy efficiency that will be at the heart of future Ethernet interfaces at Tbit/s data rates

    Effects of Selfâ Assembled Monolayer Modification of Nickel Oxide Nanoparticles Layer on the Performance and Application of Inverted Perovskite Solar Cells

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    Entirely lowâ temperature solutionâ processed (â ¤100â °C) planar pâ iâ n perovskite solar cells (PSCs) offer great potential for commercialization of rollâ toâ roll fabricated photovoltaic devices. However, the stable inorganic holeâ transporting layer (HTL) in PSCs is usually processed at high temperature (200â 500â °C), which is far beyond the tolerant temperature (â ¤150â °C) of rollâ toâ roll fabrication. In this context, inorganic NiOx nanoparticles (NPs) are an excellent candidate to serve as the HTL in PSCs, owing to their excellent solution processability at room temperature. However, the lowâ temperature processing condition is usually accompanied with defect formation, which deteriorates the film quality and device efficiency to a large extent. To suppress this setback, we used a series of benzoic acid selfassembled monolayers (SAMs) to passivate the surface defects of the NiOx NPs and found that 4â bromobenzoic acid could effectively play the role of the surface passivation. This SAM layer reduces the trapâ assisted recombination, minimizes the energy offset between the NiOx NPs and perovskite, and changes the HTL surface wettability, thus enhancing the perovskite crystallization, resulting in more stable PSCs with enhanced power conversion efficiency (PCE) of 18.4â %, exceeding the control device PCE (15.5â %). Also, we incorporated the aboveâ mentioned SAMs into flexible PSCs (Fâ PSCs) and achieved one of the highest PCE of 16.2â % on a polyethylene terephthalate (PET) substrate with a remarkable powerâ perâ weight of 26.9â Wâ gâ 1. This facile interfacial engineering method offers great potential for the largeâ scale manufacturing and commercialization of PSCs.Engineered layers: Lowâ temperature solutionâ processed NiOx nanoparticle film is usually accompanied with defect formation. Here, we find that 4â bromobenzoic acid can form a selfâ assembled monolayer (SAM) on the NiOx film and effectively tune the interfacial properties, resulting in high perovskite solar cells (PSCs) efficiency. Also, we incorporate the aboveâ mentioned SAM into flexible PSCsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138886/1/cssc201701262_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138886/2/cssc201701262.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138886/3/cssc201701262-sup-0001-misc_information.pd

    A silicon-organic hybrid platform for quantum microwave-to-optical transduction

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    Low-loss fiber optic links have the potential to connect superconducting quantum processors together over long distances to form large scale quantum networks. A key component of these future networks is a quantum transducer that coherently and bidirectionally converts photons from microwave frequencies to optical frequencies. We present a platform for electro-optic photon conversion based on silicon-organic hybrid photonics. Our device combines high quality factor microwave and optical resonators with an electro-optic polymer cladding to perform microwave-to-optical photon conversion from 6.7 GHz to 193 THz (1558 nm). The device achieves an electro-optic coupling rate of 590 Hz in a millikelvin dilution refrigerator environment. We use an optical heterodyne measurement technique to demonstrate the single-sideband nature of the conversion with a selectivity of approximately 10 dB. We analyze the effects of stray light in our device and suggest ways in which this can be mitigated. Finally, we present initial results on high-impedance spiral resonators designed to increase the electro-optic coupling
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