1,721,219 research outputs found
Fibre DFB lasers in a 4x10 Gbit/s WDM link with a single sinc-sampled fibre grating dispersion compensator
No full textWDM transmission and dispersion compensation at 40 Gbit/s over 200 km standard fibre is demonstrated on a 100 GHz grid using four high power single-polarisation single-sided output DFB fibre laser based transmitters and a single 4 channel WDM chirped fibre Bragg grating dispersion compensator
Equalisation of spectral non-uniformities in broad-band chirped fibre gratings
No full textThe authors present a novel application of apodisation to equalise the spectral non-uniformities caused by cladding-mode losses in broad-band chirped fibre Bragg gratings
Approaching the optimum erbium-doped fibre amplifier (EDFA)
No full textEDFAs are now established as key components for future high-speed communication networks. Research is therefore aimed at optimising the amplifier design. Current issues are optimal pump efficiency, spectral gain-shaping, material constraints and choice of pump wavelength
Multicore rare-earth doped fibres; application to amplifiers, filters and lasers
No full textWavelength division multiplexing (WDM) is the preferred choice for expanding the capacity of optical communication systems. Using this technique bit rates exceeding 1 Terabits/s have been demonstrated. However to fully exploit the potential of WDM several key device developments are required. This report describes the results of an experimental program, Multicore rare-earth doped fibres; application to amplifiers, filters and lasers funded under the ROPA scheme and targeted at new devices for WDM applications. The proposed program covered a three year program however funding was only awarded for two years. The key thrusts of the original submission were to introduce spatial hole burning into rare earth doped devices to controllably induce effective inhomogeneous broadening into the gain/loss medium. It was proposed to develop and optimise twincore erbium doped fibres to provide spatial hole burning and thus effective inhomogeneous broadening in the gain/loss medium. The development of channel equalising optical amplifiers, multi-wavelength and single frequency fibre lasers as well as passive tracking optical filters was targeted. These objectives were met. In addition multi-wavelength DFB fibre lasers have been developed as telecommunication sources and also applied to in-line pump a polarisation insensitive phase conjugator and as an active fibre temperature and strain sensor. Finally, a multi-wavelength (12 channel) Brillouin fibre laser has been demonstrated<br/
AM and FM response of an erbium-doped fibre amplifier for modulation frequencies up to 15GHz
No full textWe report the first measurement of the AM and FM response of an erbium-doped fiber amplifier. The amplifier gain and phase are constant for signal modulation frequencies between 130 MHz and 15 GHz, for both amplitude modulated (AM) and frequency modulated (FM) signals
1.55 micron phase-shifted distributed feedback fibre laser
No full textThe authors report the experimental realisation of a 10cm long 1.55µm Er3+-doped DFB fibre laser, with a permanent phase shift incorporated into the fibre grating during writing. Output powers of 1mW and an optical linewidth of 13kHz are observed
Fibre Bragg gratings; application to lasers and amplifiers
No full textFibre Bragg gratings are simple versatile devices which will have a major impact on the design of optical amplifiers and lasers. Applications include EDFA gain stabilising and spectrum flattening filters, pump reflection filters, as well as wavelength stable distributed feedback fibre laser and hybrid semiconductor fibre grating feedback laser sources for WDM networks. The latest developments in these areas will be reviewed
Theoretical modelling of erbium doped fibre amplifiers with excited state absorption
No full textNumerical solution of a general rate-equation model of an erbium-doped fiber amplifier highlights several important features of the device. A difference in strong-signal gain between copropagating and counterpropagating signal pump schemes in the presence of pump excited-state absorption is predicted, and this is confirmed by experiment. The detriment in the noise figure previously associated with counterpropagating schemes for only small-signal conditions is shown to be similar for strong signals, corresponding to a power-amplifier operating regime. In addition, a correction to the noise figure is given for the limit of a low-gain amplifier
Demonstration of standard fibre transmission limited by third order dispersion
No full textWe report experimental demonstration of third order dispersion limited transmission using midspan spectral inversion, 2.5ps pulses, and 105km standard fibre. The use of Fabry-Perot filters for partial compensation of third order dispersion is propose
Optical amplifier technologies in new generation optical systems
No full textThe erbium-doped fibre amplifier (EDFA) has developed rapidly since its announcement in 1987. The EDFA is now established as a key component for future high-speed, silica-based optical fibre communication networks operating at a wavelength of 1.55µm. Its major attributes are high gain, high efficiency, low noise and potential multichannel operation with low interchannel crosstalk. Expected applications are as fibre power-amplifiers in transmission systems and distribution networks, as signal repeaters in point-to-point optical links, as fibre pre-amplifiers in amplifier/receiver combinations and as distributed fibre amplifiers for soliton propagation
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