1,721,024 research outputs found
Properties and application of germanium sulphide glass
No full textChalcogenide glasses, especially sulphide glasses, are becoming more and more important for the fabrication of optoelectronic devices in part because of the high nonlinearity, strong photosensitivity and other unique properties they have (1-3). Traditionally, the sulphide glasses are made in bulk form by traditional melt-quenching method in the quartz ampoule. The bulk glasses are then reprocessed to form fibre or planar waveguides. In this research work, the germanium sulphide glass has been characterized by a series of scientific methods including Raman, FT-IR, UV-VIS, DTA, SEM and XRD. From the analysis results, we can identify the properties of germanium sulphide glass which has shown the high potential for the fabrication of the germanium sulphide glass optical fibres and planar waveguides.Key results: The germanium sulphide glass properties have been characterized by SEM, Raman, FT-IR, UV-VIS, DTA, and XRD
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
Tapered silicon optical fibers
No full textThe tapering of silicon optical fibers is demonstrated using a fusion splicer. The silicon fibers are fabricated using a high pressure chemical deposition technique to deposit an amorphous silicon core inside a silica capillary and the tapering is performed in a separate post-process. Optical and material characterization has revealed a smooth transition region leading to a uniform tapered waist that are both simultaneously crystallized to yield a solid polysilicon core. The strong mode confinement and low taper loss measured in the silicon fibers verifies this tapering approach for the fabrication of structures with nanoscale core dimensions.<br/
Low power resettable optical fuse based on the amorphous silicon ARROW fiber
No full textWe present a silicon antiresonance reflecting optical (ARROW) fiber that has power dependent transmission properties. When the throughput power exceeds a nominal value the transmission band structure closes and the fiber can no longer transmit light
Fiber-based semiconductor resonators for nonlinear photonics
No full textThe escalation of global communication traffic has intensified the need for faster data processing techniques and systems. A combination of excessive browsing and downloading from of the world-wide web and high definition television technologies necessitates a replacement of today’s electronic-based data processing with all-optical systems. The light signal, which is carried within thin strands of optical fibre, will be manipulated at speeds and capacities far beyond the capability of existing electronics without the signal having to leave the transmitting fibre. To date, signal regeneration, switching, and encoding/decoding of information have all been demonstrated in conventional silica-based optical fibres. However, the long fibre lengths and high powers necessary to achieve this represent a significant drawback. In order to realize efficient, compact and ultrafast data processing schemes with low energy consumption new fibres will have to be fabricated that incorporate enhanced material functionalities such as high nonlinearities. A recent and promising new fibre platform that incorporates semiconductor materials into the core of a silica glass cladding has opened a route to realize this goal. In this poster, I will describe my research on the demonstration of all-optical signal processing in micron-sized resonators fabricated from silicon core optical fibres
Direct synthesis of germanium sulphide glass planar waveguides by chemical vapour deposition (CVD)
No full textGermanium sulphide glass has been deposited on CaF2 and Schott N-PSK58 glass substrates directly by chemical vapour deposition (CVD). The CVD process has shown the high potential for germanium sulphide glass planar waveguides fabrication
Deposition and characterization of germanium sulphide glass planar waveguides
No full textGermanium sulphide glass thin films have been deposited on CaF2 and Schott N-PSK58 glass substrates directly by means of chemical vapor deposition (CVD). The deposition rate of germanium sulphide glass film by this CVD process is estimated about 12µm/hr at 500°C. These films have been characterized by micro-Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Their transmission range extends from 0.5µm to 7µm measured by UV-VIS-NIR and FT-IR spectroscopy. The refractive index of germanium sulphide glass film measured by prism coupling technique was 2.093±0.008 and the waveguide loss measured at 632.8nm by He-Ne laser was 2.1±0.3 dB/cm
Tunable continuous wave emission via phase-matched second harmonic generation in a ZnSe microcylindrical resonator
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Laser crystallisation of semiconductor core optical fibres
No full textA laser annealing technique is used to crystallise the core of an amorphous silicon optical fibre. The core of the resulting fibre has high material quality and its optical transmission losses are dramatically reduced
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
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