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We demonstrate an ultra compact integrated Silicon receiver for DQPSK signals made by two tunable microring resonators and four Germanium photodetectors. We report device characterization and operation for signals ranging from 10 to 20 Gbaud.
High bandwidth 2 µm wavelength surface normal p-i-n photodiodes using a high indium-content InGaAs strain-relaxed absorbing layer clad by p and n doped AlInGaAs layers are realised. A parabolic grading was used to relax the lattice constant from that of the InP substrate. We compare structures with different p-doping profiles and absorber thicknesses to achieve a 3-dB bandwidth of around 10 GHz while...
This paper introduces a novel concept for fabrication of subwavelength grating based beam shaping elements. The optical nano-hair structures are made from high-κ dielectrics using nano-patterning techniques and an atomic layer deposition tool.
THE human brain dynamics can be studied based on the fast-neuronal and slow-hemodynamic signals. Referring to the available brain imaging techniques, the electroencephalography (EEG) and Magnetoencephalography (MEG) can only measure the fast-neuronal signal. Positron-emission-tomography (PET) and Functional-magnetic-resonance-imaging (fMRI) also can measure only the slow-hemodynamic signal. However,...
Non-linear properties of quantum-dot and quantum-dash lasers under dual-mode optical injection are investigated experimentally, showing higher nonlinearity of quantum-dash lasers. Frequency response measurements show equal 3 dB modulation bandwidth of 8 GHz.
Resonance tuning characteristics of a plasmonic photonic crystal nanostructure under uniaxial compressive and tensile strains were investigated. The plasmonic device consists of a periodic array of metal-coated polymer nanoposts fabricated using a replica molding process.Applied strains regulate the period of the array, leading to flexible and repeatable resonance tuning of localized plasmons.
We report the first integrated refractometric sensor capable of detecting atmospheric CO2 gas concentration levels. The sensor employs a microring resonator functionalized with a guanidine polymer and can detect CO2 concentrations down to 250ppm with a 25ppm resolution.
Tandem LEDs in which active regions are connected by tunnel junctions show extraordinary efficiency improvement when compared with traditional LEDs and this is explained by relatively reduced forward voltage and more uniform carrier distribution.
We focus on the plasmon-enhanced emission output of the amorphous silicon quantum dots (a-Si QDs) light emitters with the Ag/SiOx:a-Si QDs/Ag cavity, through the coupling between the a-Si QDs and localized surface plasmons polaritons (LSPPs).
We demonstrate a strong enhancement of second harmonic generation based on a three-layered super absorbing metasurface consisting of an ultrathin spacer layer sandwiched by an array of random metallic nanoparticles and a metal ground plate.
High-power, long-wavelength InP-based diode lasers emitting around 1.5 µm are needed for pumping solid-state lasers, direct-diode imaging applications, and eye-safe free-space optical communications. Optical systems significantly benefit from diode lasers with high wallplug efficiency (WPE), high brightness and reduced temperature sensitivity. Early work on 1.5 µm-emitting low-power (≤ 20 mW) lasers...
Diode laser bars with optimized epitaxial designs, long resonators and passivated facets deliver joule-class millisecond pulses (kilowatts of peak power) with the properties needed by advanced high-energy-class solid-state laser systems, at brightness over 3 MW/(cm2sr).
We review recent progress of space division multiplexing technologies using few-mode and multi-core fibers. Heterogeneous design has been demonstrated as a key technology for dense core arrangement. Highest spatial channel density and over-100 spatial channel count were realized with a heterogeneous 36-core 3-mode fiber.
Using an inverse design method that explores the full design space of fabricable devices, we demonstrate a compact wavelength splitter with a footprint of only 2.8 × 2.8 m. The device has low insertion loss (2 – 4 dB), high contrast (12 – 17 dB), and is robust to fabrication imperfections.
We present a free-space coherent communication link employing orbital angular momentum (OAM) multiplexing using polarization diversified 2D–3D hybrid photonic integrated circuits (PICs). The PICs support multiplexing/demultiplexing of up to 15-OAM states with dual polarizations. We characterize the hybrid device, including phase errors and crosstalk performance. Then, we use two hybrid PICs for a...
We review possible implementations of coherent anti-Stokes Raman scattering using nanophotonic waveguide circuits. Enhancement mechanisms and limitations are discussed.
We produced a 3–15-ns CO2 laser pulse with 1011 W/cm2 for an efficient extreme ultraviolet (EUV) source by rare earth element of Gd. The EUV emission was observed a sharp spectral structure at 6.79 nm.
The technique of multiheterodyne detection is applied to a dynamically varying pulse train, the amplitude and frequency of which are changing at hundreds of kilohertz rates. Unlike traditional pulse reconstruction techniques, time-resolved multiheterodyne provides a method to measure the optical intensity and phase of a pulse train in time bins of approximately 100 ns duration. 10 GHz return-to-zeros...
A novel polling-based PON link monitoring scheme is proposed for efficient fault decision based on optical 2D-pre-coding. We model correlation distance and obtain via simulation that a lower bound of the SIR is ∼21dB.
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