1,720,985 research outputs found
Photosensitivity in germanium-free antimony doped alumino-silicate optical fibre prepared by MCVD
No full textBragg gratings with index modulations of ~3 x 104 is reported in antimony (Sb) codoped fibres. Gratings in germanium-free fibres of different Sb concentration are analysed and those in higher concentration fibres are found the more temperature-resistant
A novel distributed ODCMA architecture based on simultaneous transmission of 16-chip OCDMA signals and clock pulses
No full textWe demonstrate a distributed bi-directional OCDMA architecture suitable for secured access networks, incorporating a fast 16-chip code-tunable encoder based on a uniform fibre Bragg grating and fixed-code superstructure fibre Bragg grating. This simple architecture eliminates the requirement for expensive laser transmitters at the subscribers' terminal
Simple dynamically reconfigurable OCDMA encoder/decoder based on a uniform fiber Bragg grating
No full textA simple reconfigurable phase coding OCDMA coder/decoder based on a uniform fiber Bragg grating is proposed and demonstrated. Experiments using the temperature-tunable 8-chip, 20 Gchip/s bipolar coding/decoding gratings show its excellent code recognition features
16-bit multilevel reconfigurable phase encoder for all optical header generation/recognition based on a uniform fibre Bragg grating
No full textWe demonstrate a simple, dynamically tunable phase encoder/decoder for use in reconfigurable all-optical packet switched networks. The device is based on a uniform fibre Bragg grating and has 16 phase-tunable elements. Excellent auto-/cross-correlation features and error free BER operation are obtained
Investigation into the photosensitivity of germanium-free antimony co-doped alumino-silicate optical fibres
No full textPhotosensitivity of different concentrations of antimony (Sb) codoped alumino-silicate optical fibres are analysed. Bragg gratings with index modulations of ~3 x 10-4 are reported. The temperature stability of the gratings is tested and those in higher concentration fibres are found to be more temperature-resistant
Reconfigurable multi-level phase shift keying encoder-decoder for all-optical networks
Full text linkWe demonstrate the application of a uniform Bragg grating as a dynamically reconfigurable phase encoder-decoder for optical systems. Precise discrete phase modulation between chips is obtained simply by heating segments along the grating with fine resistive wires. Its reliability to generate and recognize various phase code sequences is demonstrated in a 16-chip 20-Gchip/s quaternary phase-shift keying coherent optical code-division multiple access experiment. The bit-error-rate response is also included to highlight its performance
Effects of large compressive-stresses on photosensitive optical fibres and Bragg gratings
No full textA study on the effects of axial stresses in optical fibres is presented. Results show large induced losses dependent on core-composition and ultra-violet light exposure. Additionally a stress-induced increase in gratings-strength is observed
Reconfigurable Phase Shifted Fiber Bragg Grating Using Localized Micro-Strain
No full textA simple and precise method for tuning of localized phase shift in fiber Bragg grating (FBG) using mechanical micro-strain is proposed and experimentally verified. Positive and negative continuous phase shifts tuning between 0 and +π/-π in a uniform FBG is experimentally demonstrated using confined micro-strain in a beam bending configuration. The magnitudes of the temporary phase shifts can be linearly controlled by changing the load displacement, with set-and-forget capability
Tuneable second harmonic generation in long periodically poled optical fibres
No full textA widely tuneable second harmonic generator in a periodically poled germanosilicate optical fibre is demonstrated for the first time. Broadband wavelength tuning of 27.8nm is achieved using a highly efficient compression tuneable package demonstrated with fibre Bragg gratings
Improving signal quality in a spectrum-sliced WDM system using SOA-based noise reduction
No full textWe present an experimental and numerical study into the filtering effects in a spectrum-sliced incoherent light system incorporating a semiconductor optical amplifier (SOA) for noise reduction. Techniques to reduce the signal degradation caused by post-SOA filtering are investigated. The alignment of the receiver/demultiplexer filter relative to the input spectrum-slice is demonstrated to have a noticeable impact on the received signal quality. We also show that the linewidth enhancement factor a of the SOA has a marked effect on the observed spectral distortion, which results in a strong dependence of the received signal quality on a. Our results illustrate the potential to improve system performance by optimized SOA design
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