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Laser filamentation provides a convenient source of broadband, intrinsically short radiation that is an ideal source for impulsive vibrational and rotational excitation of polyatomic molecules. Here we present experimental and theoretical results achieved to date.
We describe a 100 mJ three component ytterbium based laser system operating at 1030 nm. Capabilities of both temporal pulse shaping and efficient active/passive spatial shaping for amplification in a 100 J system are incorporated.
We explore light diffraction by parity-time-symmetric metasurfaces. Such structures can lead to one-sided diffraction when operating close to their exceptional points. In this regime, the negative diffraction orders are eliminated while the positive are enhanced.
We experimentally demonstrate sinusoidal anti-coupling silicon-on-insulator strip waveguides, separated by 200 nm, that have a minimum inter-waveguide crosstalk suppression of 26.8 dB within the C-band for the fundamental transverse electric mode.
We report a PAM-ECDMA PON system with 2.5-fold performance improvement over the prior NRZ-ECDMA system. Error-free transmission of two channels in an 8-user 25.6 Gb/s aggregate-data-rate PON is achieved in a proof-of-principle demonstration.
A symbol rate identification method is proposed for optical signals with commonly used modulation formats. Numerical simulation and experimental results show it is accurate and robust to different link impairments.
Electrical tunability of saturable absorption is demonstrated in a graphene/SOI hybrid waveguide. The saturation modulation depth is tunable between 0 and 2.2 dB (∼0–40% decrease of absorption at saturation), with saturation powers between ∼1.25–2.5 W.
An ultrafast all-optical simultaneous wavelength and mode conversion scheme is purposed based on intermodal nonlinear wave mixing, with the capability of switching state of polarization and mode degeneracy orientation in few-mode fibers with high efficiency.
We demonstrate a five-channel wavelength division multiplexed modulator module that heterogeneously integrates a 1.6nm channel-spacing arrayed-waveguide grating and a 20Gbps electroabsorption modulator array, showing the potential for 100 Gbps capacity on a 1.5×0.5 mm2 footprint.
We demonstrate all-optical photoinjection of a one-dimensional resonator inside a terahertz parallel-plate waveguide. The pulsed nature of the pump enables us to study dynamic effects where the structure is written in a reversible and fully-reconfigurable fashion, on timescales faster than the propagation of the terahertz pulse through it.
We study multimode optical solitons with up to roughly 10 spatial modes. This work provides the first evidence for solitons involving more than a few modes, and for spatiotemporal multimode soliton fission and Raman shifting.
We propose a laser distance measurement using second harmonic signal component of two-photon absorption photocurrent from a Si-APD. The proof-of-concept experiment demonstrates the accurate measurement with short data acquisition time of several tens of seconds.
Fabrication and characterization of optical leaky wave antennas with dielectric waveguides and semiconductor perturbations is presented. Directive radiation at 1550nm is measured. Detailed study on electrical modulation capability with bandwidth exceeding 75GHz is presented.
We present a tunable-wavelength, multi-color source for imaging several fluorophores simultaneously. The source is based on amplitude modulation of the seed in a chirped-pulse amplification system, followed by soliton self-frequency shift in a large-mode-area fiber.
We measure small optical beam deflections both using a Sagnac interferometer with a monitored dark port (the weak-values-based technique), or by focusing the entire beam to a split detector (the standard technique). By introducing controlled external modulations we quantify the mitigation of these sources in the weak values-based experiment versus the standard focusing experiment. In all cases, the...
We demonstrate photonics monolithically integrated in a 32 nm SOI microelectronics process, including grating couplers, tunable filters, and modulators, the first migration of zero-change CMOS photonics moving down the microelectronics technology-node ladder, from the 45nm node.
Silicon photonics devices based on Ge/SiGe structures are promising. However their integration with silicon on insulator waveguides is a challenging point. We present an innovative approach to monolithically integrate low-voltage, broadband photonic interconnection on silicon.
We design and characterize asymmetric Bragg gratings in waveguides which possess multiple reflected wavelengths. We experimentally demonstrate devices with two independent stopbands, then use finite-difference time domain software to characterize more complex grating designs.
A detection scheme for discriminating coherent states in quantum key distribution systems employing PSK is proposed. It is simple and uses only standard components. Its applicability at extremely low power levels of as low as 0.045 photons per symbol is experimentally verified.
We report a transmission of 3 Gbit/s signal over a 4-km grade-index multimode fiber within a bandwidth of 2.54 GHz using multiple-layer-overlay (MLO) modulation format, achieving a spectral efficiency of 1.18 symbols/s/Hz.
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