Sergio Nicoletti

  • Citations Per Year
Learn More
In this paper, we present the design, the fabrication and the characterization of an Arrayed Waveguide Grating (AWG) based on a SiGe graded index waveguide platform, operating at 4.5 µm. These devices were specifically designed to work together with an array of Distributed Feedback Bragg Quantum Cascade Lasers (DFB-QCL) emitting at different wavelengths.(More)
We demonstrate broadband supercontinuum generation (SCG) in a dispersion-engineered silicon-germanium waveguide. The 3 cm long waveguide is pumped by femtosecond pulses at 2.4 μm, and the generated supercontinuum extends from 1.45 to 2.79 μm (at the -30  dB point). The broadening is mainly driven by the generation of a dispersive wave in the 1.5-1.8 μm(More)
We demonstrate four wave mixing (FWM) based wavelength conversion of 40 Gbaud differential phase shift keyed (DPSK) and quadrature phase shift keyed (QPSK) signals in a 2.5 cm long silicon germanium waveguide. For a 290 mW pump power, bit error ratio (BER) measurements show approximately a 2-dB power penalty in both cases of DPSK (measured at a BER of(More)
In the last few years Mid InfraRed (MIR) photonics has received renewed interest for a variety of commercial, scientific and military applications. This paper reports the design, the fabrication and the characterization of SiGe/Si based graded index waveguides and photonics integrated devices. The thickness and the Ge concentration of the core layer were(More)
We present a systematic experimental study of the linear and nonlinear optical properties of silicon-germanium (SiGe) waveguides, conducted on samples of varying cross-sectional dimensions and Ge concentrations. The evolution of the various optical properties for waveguide widths in the range 0.3 to 2 µm and Ge concentrations varying between 10 and 30% is(More)
We report a low-power continuous wave (CW)pumped phase sensitive amplifier (PSA)-based phase regenerator implemented in a passive silicon-based waveguide. A polarization assisted (PA)-PSA, consisting of two orthogonally-polarized pumps and a phase-locked signal co-polarized to one of them, was implemented in a low-birefringence silicon germanium (SiGe)(More)
In this paper we estimate simple Taylor rules paying a particular attention to interest rate smoothing. Following English, Nelson, and Sack (2002), we employ a model in first differences to gain some insights on the presence and significance of the degree of partial adjustment as opposed to a serially correlated policy shock. Moreover, we estimate a nested(More)
We report on the advanced optical characterizations of microfabricated solid immersion lenses with 2-μm diameter, operating at λ = 642 nm. The main feature, the spot size reduction, has been investigated by applying a focused Gaussian beam of NA = 0.9. Particular illuminating beams, e.g., Bessel-Gauss beams of the zeroth and the first order, a doughnutshape(More)
We demonstrate the design, fabrication and characterization of a highly nonlinear graded-index SiGe waveguide for the conversion of mid-infrared signals to the near-infrared. Using phase-matched four-wave mixing, we report the conversion of a signal at 2.65 µm to 1.77 µm using a pump at 2.12 µm.