1,720,985 research outputs found
Ultrafast wavelength conversion via cross-phase modulation in hydrogenated amorphous silicon optical fibers
No full textWe present a characterization of the spectral modulation and wavelength shifting induced via cross-phase modulation (XPM) in a hydrogenated amorphous silicon (a-Si:H) core optical fiber. Pump-probe experiments using picosecond and femtosecond signal pulses are shown to be in good agreement with numerical simulations of the coupled nonlinear propagation equations. The large 10nm red-shifts obtained with the femtosecond probe pulses are attributed to the high Kerr nonlinearity of the a-Si:H material. Extinction ratios as high as 12dB are measured for the conversion process at telecommunications wavelengths, indicating the potential for high-speed nonlinear optical control in a-Si:H fibers and waveguides
Towards in-fiber silicon photonics
No full textThe state of the art of silicon optical fibers fabricated via the high pressure chemical deposition technique will be reviewed. The optical transmission properties of step index silicon optical fibers will be presented, including investigations of the nonlinearities that can be used for all-optical signal processing. In addition, alternative complex fiber geometries that permit sophisticated control of the propagating light will be introduced
Nonlinear transmission properties of hydrogenated amorphous silicon core fibers towards the mid-infrared regime
No full textThe nonlinear transmission properties of hydrogenated amorphous silicon (a-Si:H) core fibers are characterized from the near-infrared up to the edge of the mid-infrared regime. The results show that this material exhibits linear losses on the order of a few dB/cm, or less, over the entire wavelength range, decreasing down to a value of 0.29dB/cm at 2.7µm, and negligible nonlinear losses beyond the two-photon absorption (TPA) edge ~ 1.7µm. By measuring the dispersion of the nonlinear Kerr and TPA parameters we have found that the nonlinear figure of merit (FOMNL) increases dramatically over this region, with FOMNL > 20 around 2µm and above. This characterization demonstrates the potential for a-Si:H fibers and waveguides to find use in nonlinear applications extending beyond telecoms and into the mid-infrared regime
Semiconductor core fibres: a new platform for nonlinear optics?
No full textAdvancements in semiconductor core fibres fabricated via the high-pressure chemical deposition technique are reviewed. Transmission measurements will be presented for different core materials, including more recent nonlinear characterizations of the hydrogenated amorphous silicon fibres
Nonlinear properties of silicon optical fibers from telecoms to the mid-infrared
No full textSilicon waveguides are becoming an increasingly popular platform for nonlinear optical signal processing. The incorporation of silicon into the optical fiber geometry provides an important step towards integrating semiconductor functionality with conventional fiber infrastructures, as well as allowing for the construction of robust devices with novel waveguiding properties. In this paper we review our progress in characterizing the nonlinear transmission properties of the hydrogenated amorphous silicon (a-Si:H) core fibers fabricated using a high pressure chemical deposition technique [1]. a-Si:H is emerging as a important material for nonlinear photonics owing to its high nonlinearity, low fabrication costs, and low transmission losses. Although, to date, this material has largely been characterized at telecommunications wavelengths [2], we have recently extended our investigations to present the first characterization of both the nonlinear absorption and refractive index over a wavelength region that crosses the two-photon absorption (TPA) edge, stretching towards the mid-infrared regime. These results will be discussed in relation to future device development, where we will demonstrate the potential for all-optical control using both cross-phase and cross-absorption modulation
Ultrafast optical control using the Kerr nonlinearity in hydrogenated amorphous silicon microcylindrical resonators
No full textMicroresonators are ideal systems for probing nonlinear phenomena at low thresholds due to their small mode volumes and high quality (Q) factors. As such, they have found use both for fundamental studies of light-matter interactions as well as for applications in areas ranging from telecommunications to medicine. In particular, semiconductor-based resonators with large Kerr nonlinearities have great potential for high speed, low power all-optical processing. Here we present experiments to characterize the size of the Kerr induced resonance wavelength shifting in a hydrogenated amorphous silicon resonator and demonstrate its potential for ultrafast all-optical modulation and switching. Large wavelength shifts are observed for low pump powers due to the high nonlinearity of the amorphous silicon material and the strong mode confinement in the microcylindrical resonator. The threshold energy for switching is less than a picojoule, representing a significant step towards advantageous low power silicon-based photonic technologies
Two-photon absorption and self-phase modulation in silicon optical fibers into the mid-infrared regime
No full textNonlinear transmission is investigated in a hydrogenated amorphous silicon optical fiber extending into the mid-infrared region. Low losses past the two-photon absorption edge allow for strong spectral broadening in this important wavelength regime
Nonlinear properties of silicon optical fibers
No full textThe nonlinear transmission properties of hydrogenated amorphous silicon core fibers are characterized for short pulse propagation. The influence of the material quality and core size will be discussed in relation to device performance
High nonlinear figure of merit hydrogenated amorphous silicon optical fibers
No full textThe wavelength dependence of the nonlinear properties of hydrogenated amorphous silicon core fibers are characterized across the two-photon absorption edge. These novel fibers exhibit a significant increase in nonlinear figure of merit around 2µm
Short-wave infrared continuum generation in hydrogenated amorphous silicon fibers
No full textFour-wave mixing and broadband continuum generation are demonstrated for the first time in a small core silicon optical fiber in the short-wave infrared wavelength regime
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