Search results for "Optoelectronics"
showing 10 items of 2306 documents
Optoelectronic Module with Integrated Transceiver and Mux-Demux for Optical Interconnect Applications
2019
The design, development and improvtableement in electronic devices and components have led to the further miniaturization of the system devices and their interconnecting interfaces. Hence, reducing the size of the transmitter (Tx) chips, receiver (Rx) chips and associated components play an important role in designing a reduced/small sized optoelectronic modules for optical interconnect applications. Some of the associated components include multiplexer, demultiplexer, clock and data recovery circuits (CDR), etc. Therefore, in this paper we present an optoelectronic module with integrated transceiver (Tx-Rx) and multiplexer-demultiplexer (mux-demux) with the aim of reducing the total area o…
Ligand-Length Modification in CsPbBr3 Perovskite Nanocrystals and Bilayers with PbS Quantum Dots for Improved Photodetection Performance
2020
Nanocrystals surface chemistry engineering offers a direct approach to tune charge carrier dynamics in nanocrystals-based photodetectors. For this purpose, we have investigated the effects of altering the surface chemistry of thin films of CsPbBr3 perovskite nanocrystals produced by the doctor blading technique, via solid state ligand-exchange using 3-mercaptopropionic acid (MPA). The electrical and electro-optical properties of photovoltaic and photoconductor devices were improved after the MPA ligand exchange, mainly because of a mobility increase up to 5 ×
Artificial dielectric optical structures: A challenge for nanofabrication
1998
Diffractive optical components can be made using multiple level kinoforms or single level artificial dielectric structures. The latter require the fabrication of pillars of equal depth but differing width and spacing. As a demonstration device, the diffractive optic equivalent of a wedge has been made in GaAs for use at 1.15 μm. The need for all pillars to have the same height was met by using a selective etch and a very thin etch-stop layer on AlGaAs. The experimental diffraction efficiency was 87.8%, among the best ever obtained and close to the theoretical maximum of 97.6%. © 1998 American Vacuum Society.
Scalable Electro-Optic Control of Localized Bistable Switching in Broad-Area VCSELs Using Reconfigurable Funnel Waveguides
2017
We demonstrate a steplike optical modulation based on the activation and deactivation of a bistable localized structure using a photoinduced and reconfigurable miniaturized 30 × 30 μm electroactivated funnel waveguide. Control of a single 10-μm-diameter spot in a 200-μm-diameter vertical-cavity surfaceemitting laser at 980 nm is achieved modulating the phase of an exciting beam in the specific position of the spot in the cavity. This localized on-off response can be scaled into arrays and offer a possible route to fast integrated optical logical functions and memory at low intensities at near-infrared wavelengths.
Bottle microresonator with actively stabilized evanescent coupling
2011
The evanescent coupling of light between a whispering-gallery-mode bottle microresonator and a sub-wavelength-diameter coupling fiber is actively stabilized by means of a Pound-Drever-Hall technique. We demonstrate the stabilization of a critically coupled resonator with a control bandwidth of 0.1 Hz, yielding a residual transmission of (9 \pm 3) \times 10^-3 for more than an hour. Simultaneously, the frequency of the resonator mode is actively stabilized.
Efficient Monolithic Perovskite/Perovskite Tandem Solar Cells
2016
Thin-film solar cells suffer from various types of recombination, of which leakage current usually dominates at lower voltages. Herein, we demonstrate first a three-order reduction of the shunt loss mechanism in planar methylammonium lead iodide perovskite solar cells by replacing the commonly used hole transport layer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with a better hole-selective polyarylamine. As a result, these cells exhibit superior operation under reduced light conditions, which we demonstrate for the extreme case of moonlight irradiance, at which open-circuit voltages of 530 mV can still be obtained. By the shunt removal we also observe the VOC to dro…
Reversible Digital And Holographic Optical Storafe In Polymeric Liquid Crystals (PLC)
1987
A new reversible optical storage technique based on azo dye containing liquid crystalline polymers and copolymers is described. Monodomain films of the polymers were used as storage medium. Digital and holographic information was stored and reconstructed. The stored information can be erased and the writing process is repeatable. The storage process is explained in terms of a transcis isomerization of the mesogen inducing local director field distortions.
Amplified spontaneous emission of glass forming DCM derivatives in PMMA films
2014
4-(dicyanomethylene)-2-methyl- 6-(p-dimethylaminostyryl)-4H-pyran ( DCM ) is well known red laser dye which can be used also in solid state organic lasers. The lowest threshold value of amplified spontaneous emission was achieved by doping 2wt% of DCM molecule in tris-(8-hydroxy quinoline) aluminium (Alq
Inverted Solution Processable OLEDs Using a Metal Oxide as an Electron Injection Contact.
2007
A new type of bottom-emission electroluminescent device is described in which a metal oxide is used as the electron-injecting contact. The preparation of such a device is simple. It consists of the deposition of a thin layer of a metal oxide on top of an indium tin oxide covered glass substrate, followed by the solution processing of the light-emitting layer and subsequently the deposition of a high-workfunction (air-stable) metal anode. This architecture allows for a low-cost electroluminescent device because no rigorous encapsulation is required. Electroluminescence with a high brightness reaching 5700 cd m–2 is observed at voltages as low as 8 V, demonstrating the potential of this new a…
Electroactive Liquid Crystalline Polymers ☆
2017
As with low molecular mass liquid crystals, the polymeric liquid crystalline compounds show many possibilities for interaction with electrical fields. Charge transport via the aromatic cores allows the construction of light emitting devices, field effect transistors and photovoltaic cells. The order of the liquid crystalline phases helps to improve intramolecular charge transfer and the mobility allows easy alignment. Liquid crystalline polymers with ferroelectric phases can be used in fast switching optical devices. Their unique switching mechanism proceeds under reduced interaction with the polymer chains. The combination of liquid crystallinity with elastomer networks leads to electromec…