IEE Proceedings - Optoelectronics
Volume 145, Issue 4, August 1998
Volumes & issues:
Volume 145, Issue 4
August 1998
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- Author(s): M. Karásek and J.C. van der Plaats
- Source: IEE Proceedings - Optoelectronics, Volume 145, Issue 4, p. 205 –210
- DOI: 10.1049/ip-opt:19982140
- Type: Article
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p.
205
–210
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Transient-gain response of optical amplifiers to addition/removal of channels represents a major problem in multiwavelength optical networks. To avoid error bursts in the surviving channels, signal-power fluctuations due to channel addition or removal caused by network reconfigurations or line failures must be minimised. The recently proposed and experimentally tested inversion and gain-locking technique for erbium-doped fibre amplifiers (EDFAs), based on pump power loss monitoring, is analysed. The analysis is based on the application of a comprehensive large-signal numerical model which incorporates temporal properties and the downstream and upstream propagation of signal, pump and amplified spontaneous emission (ASE) in an erbium-doped fibre amplifier. It follows from the theoretical investigation that the surviving channel-power excursion in a single 20 dB gain EDFA can be reduced to 0.3 dB through the addition/removal of six channels in an eight-channel multiwavelength system when the pump-power-feedback parameters are appropriately selected. - Author(s): A.V.T. Cartaxo and J.A.P. Morgado
- Source: IEE Proceedings - Optoelectronics, Volume 145, Issue 4, p. 211 –216
- DOI: 10.1049/ip-opt:19982141
- Type: Article
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p.
211
–216
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A rigorous small-signal theory for linear and dispersive singlemode fibre communication systems operating at the zero-dispersion wavelength is presented. From this theory, the intensity and frequency noise transmission along the singlemode fibre is assessed. The new theory shows excellent consistency with accurate numerical simulations of intensity and frequency noise spectra after singlemode fibre transmission. Theoretical and simulation results show that fibre transmission at zero-dispersion wavelength leads to intensity and frequency noise spectra at fibre output, similar to intensity and frequency noise spectra, respectively, at the input to the fibre. Accordingly, at zero-dispersion wavelength, second-order dispersion effects on the intensity and frequency noise are irrelevant even for ultra-high bit rates and long-haul fibre links. - Author(s): J.H. Swoger ; J.G. Simmons ; D.A. Thompson
- Source: IEE Proceedings - Optoelectronics, Volume 145, Issue 4, p. 217 –222
- DOI: 10.1049/ip-opt:19982142
- Type: Article
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p.
217
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A numerical model of the carrier and photon densities in the active region of a non-uniformly pumped semiconductor laser is described. This model has been applied to the case of 2-contact, split-electrode ridge-waveguide InGaAsP/InP lasers, in order to simulate the self-sustained pulsations that have been observed in these devices. The resulting simulations show two different types of self-sustained pulsations: oscillations due to repetitive Q-switching, and a self-perpetuating modulation of a continuously lasing output. The driving force in both cases is the saturation of the absorption in the laser cavity: it is not necessary to introduce additional mechanisms such as mode competition or instability in order to simulate these two types of behaviour. The authors have characterised the output power, frequency and pulse shape for a series of devices that exemplify these two types of self-pulsing operation, and compared the results to experimental observations in the literature. - Author(s): G.R. Chakravarty ; V. Priye ; B.P. Pal ; K. Thyagarajan
- Source: IEE Proceedings - Optoelectronics, Volume 145, Issue 4, p. 223 –226
- DOI: 10.1049/ip-opt:19982143
- Type: Article
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p.
223
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The role of a dielectric buffer in the polarisation selectivity of a PbSe (cladding)/BaF2/CaF2 waveguide having transmission passband in the infrared wavelength of 3.4 µm is investigated. Results indicate that the presence of a buffer layer can greatly enhance the polarisation extinction ratio in such semiconductor-clad waveguides, enabling their use as a polarisation selector. - Author(s): A. Driessen ; H.J.W.M. Hoekstra ; F. Horst ; G.J.M. Krijnen ; B.J. Offrein ; J.B.P. van Schoot ; P.V. Lambeck ; Th.J.A. Popma
- Source: IEE Proceedings - Optoelectronics, Volume 145, Issue 4, p. 227 –235
- DOI: 10.1049/ip-opt:19982144
- Type: Article
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p.
227
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All-optical data processing is highly desirable in optical data-communication networks because of the increasing need of bandwidth and optical transparency. The paper presents an evaluation of integrated optics device concepts, discusses materials requirements and gives experimental results of own work on devices based on silicon technology with hybrid integration of polymers as a nonlinear material. - Author(s): L.W.K. Yim ; A.B. Davey ; W.A. Crossland
- Source: IEE Proceedings - Optoelectronics, Volume 145, Issue 4, p. 236 –242
- DOI: 10.1049/ip-opt:19982145
- Type: Article
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p.
236
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The paper describes operation parameters of light valves (or optically addressed spatial light modulators (OASLMs)) which incorporate the pixellated binary (SCE 13) and a pixellated analogue (Chisso 2004) switching liquid crystal effect devices. The four operation parameters, namely the spatial resolution at 50% modulation, switching speed (or frame rate), sensitivity, and contrast ratio for the SCE 13 device were 54 lines/mm, 3.5 kHz, 2.3 mW/cm2 and 17:1, respectively. Those of its Chisso 2004 counterpart were 52 lines/mm, 2.5 kHz, 2.5 mW/cm2 and 10.8:1. Modulated output images acquired by writing the United States Air Force (USAF) resolution chart and a slide on the photosensitive layer of the light valve are shown. - Author(s): K. Suto ; T. Kimura ; T. Saito
- Source: IEE Proceedings - Optoelectronics, Volume 145, Issue 4, p. 243 –247
- DOI: 10.1049/ip-opt:19982146
- Type: Article
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p.
243
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The intensity noise of a CW-operated semiconductor Raman laser with a tapered waveguide structure with GaP core and AlxGa1-xP cladding layers has been measured and it has been found that the noise spectral intensity in the frequency range 10 Hz–100 kHz was reduced to 34 dB below that of the incident pump light under saturation conditions. This effect has been interpreted as coupling between the pump light, the first Stokes light and the second Stokes light, assuming a very small contribution of nonlinear absorption. - Author(s): J.K. Sheu ; Y.K. Su ; S.J. Chang ; M.J. Jou ; C.C. Liu ; G.C. Chi
- Source: IEE Proceedings - Optoelectronics, Volume 145, Issue 4, p. 248 –252
- DOI: 10.1049/ip-opt:19982147
- Type: Article
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p.
248
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This paper investigates the differences of wafer-bonded n-(Al0.7Ga0.3)0.5In0.5P/n-GaP, n-Ga0.5In0.5P/n-GaP and n-GaP/n-GaP heterointerfaces. The current–voltage characteristics have been demonstrated to be a result of different wafer cleaning methods. Bonded interfaces were also characterised by scanning electron microscopy and transmission electron microscopy. In addition, an (AlxGa1-x)0.5In0.5P light-emitting diode (LED) was fabricated by wafer direct bonding technique. The luminous intensity of the wafer-bonded (AlxGa1-x)0.5In0.5P/GaP LED is about two times brighter than the conventional device with an absorbing GaAs substrate.
Modelling of a pump-power-loss-controlled gain-locking system for EDFA application in WDM transmission systems
Intensity and frequency noise transmission along singlemode fibre at zero-dispersion wavelength
Modelling of self-sustained pulsations in non-uniformly pumped semiconductor lasers
Polariser based on a PbSe-clad optical waveguide in the infrared wavelength: The role of a buffer layer
All-optical integrated optic devices: A hybrid approach
Comparison of operation parameters between binary and analogue switching pixellated light valves
Output power saturation characteristics of the CW-operated semiconductor Raman laser
Investigation of wafer-bonded (AlxGa1-x)0.5In0.5P/GaP light-emitting diodes
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