1,721,203 research outputs found
Efficient Second-Harmonic Generation in Si-GaP Asymmetric Coupled-Quantum-Well Waveguides
No full textWe present a theoretical investigation of efficient second harmonic generation in the cubic lattice-matched N-doped Si/GsP multiple quantum well system integrated in a strip waveguide in the silicon-on-insulator platform. A "giant" second-order nonlinear optical susceptibility is obtained in an asymmetric coupled quantum well (ACQW) stack by engineering the 1-2 and 1-3 inter-subband spacings for resonance at both a similar to 4 mu m pump wavelength and a similar to 2 mu m harmonic wavelength. Generation has been simulated as a function of the quantum well physical parameters, the infrared absorption losses, and the detuning from the double resonance condition. For TM pumps at 3.75 mu m and 4.24 mu m, a chi((2))(zzz) value ranging from 7.73 x 103 pm/V to 1.13 x 104 pm/V has been calculated and a maximum conversion efficiency ranging between 1.23%/W and 1.68%/W has been obtained, where the waveguide coherence length was 5.57 mu m and 6.16 mu m
Harmonic Generation in GaP/Si and GaP/AlP Superlattice-Based Waveguides
No full textWe present a theoretical investigation, based on the tight-binding Hamiltonian, of efficient second harmonic generation (SHG) in the lattice-matched N-doped (GaP)(N) / (Si-2)(M) short-period superlattice integrated in a strip waveguide in the silicon-on-insulator platform. The X-(2) spectrum has been simulated as a function of the number of the monolayers for the "non-relaxed" heterointerfaces. For TM pumps at 5.05 mu m a X-(2) value of 1.25x10(4) pm/V has been calculated for the (GaP)(1) / (Si-2)(2) superlattice giving a maximum conversion efficiency around 1.14%/W, where the waveguide coherence length was 3.37 mu m and the waveguide width was 2 mu m. Moreover the (GaP)(3) / (AlP)(3) superlattice is proposed for SHG with surface incidence, operating in the mid infrared with X-(2) value of 1.8x10(4) pm/V. Finally, the X-(2) spectrum for difference frequency generation is reported for (GaP)(5) / (Si-2)(1) and (GaP)(4) / (Si-2)(2)
Modeling and Simulation of a High Sensitivity E-Field Sensor based on Disk Resonator and MOS Structure in SOI Technology
No full textA novel miniaturised high sensitivity Electric-field sensor based on a whispering gallery mode disk resonator is presented This device joins the potentials of silicon-on-insulator (SOI) technology with the potentials of high Q-factor disk resonator
Mid-IR Optical and Non Linear Properties of Germanium on Silicon Optical Waveguides
No full textThe influence of Germanium-on-Silicon waveguide geometries on single-mode and multimode operations as well as on zero birefringence conditions has been deeply investigated in the mid infrared spectrum. The design equations to estimate the single mode conditions have been carried out and interpolated by exponential functions. Moreover, the group velocity dispersion and third-order dispersion have been investigated in the range 3-6 mu m as a function of various waveguide geometries. Finally, nonlinear properties, for instance the modal Raman gain, have been investigated, comparing with Silicon-on-Insulator waveguides. The set of results identifies accurate guidelines for the design of these optical waveguides for several applications
Accurate physical modelling of multi quantum well ring lasers
No full textThe aim of this paper is to present a model including the fundamental physical effects of the multi quantum well (MQW) ring laser for the understanding of the optical mode behaviour and the control of the oscillating mode in semiconductor injection ring laser. The fully physical model is derived from a quantum mechanical approach and don't depend on any semi-empirical approximation. The ring laser behaviour is related to its physical and technological constraints, as the backscattering effect and ring radius
Tecniche di anestesia in corso di litotripsia extracorporea ad onde d' urto: revisione critica
No full textAnti-parity-time-symmetric integrated optical gyroscopes
No full textParity-time-symmetric optical gyroscopes are gaining interest for the enhanced sensitivity shown by exceptional points. The real splitting of anti-PT-symmetric gyroscopes is more reliable for stability and readout scheme than the complex splitting of parity-time-symmetric gyroscopes
Thermal and Stress Influence on Performance of SOI Racetrack Resonator Raman Lasers
No full textIn this paper, the detailed modeling of Raman lasers in silicon-on-insulator guided-wave racetrack resonant microcavities is developed. Modeling based on full-vectorial equations, including thermal and stress effects, is presented for the first time. Simulation results are compared with experimental and theoretical results in the literature, demonstrating very good agreement. Moreover, parametric investigations, including waveguide sizes, pump and Stokes coupling factors, cavity shape, polarization states, and waveguide orientation are presented; and the effects of these characteristics in conjunction with thermal and stress influence on laser features are discussed
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