1,720,960 research outputs found
Intensity noise reduction of incoherent light using semiconductor optical amplifiers
No full textWe review the use of a semiconductor optical amplifier for intensity noise reduction of incoherent sources and describe our recent experimental and theoretical work in this area. We focus in particular on understanding the physical mechanisms underpinning the noise reduction process and which govern the associated spectral broadening. We also describe in detail how onward filtering and transmission degrade the noise reduction and impact use of the technique within a high density spectrum-sliced system
Relaxation oscillation noise suppression in fibre DFB lasers using a semiconductor optical amplifier
No full textWe report the experimental results of a simple, all optical technique to reduce the relative intensity noise peak of a fibre distributed feedback laser. A noise reduction of 30dB is achieved
Intensity noise suppression in fibre DFB laser using gain saturated SOA
No full textExperimental results of a simple, all-optical technique to reduce low-frequency intensity noise in an Er-Yb codoped fibre distributed feedback (DFB) laser are reported. This method utilises the gain dynamics of a saturated semiconductor optical amplifier (SOA) to produce a reduction of 30dB in the relaxation oscillation noise component of the fibre laser
Filtering effects in a spectrum-sliced WDM system using SOA-based noise reduction
No full textWe present an experimental investigation into the effects of receiver filtering on the intensity noise in a spectrum-sliced incoherent light system incorporating semiconductor optical amplifier (SOA) based noise reduction. Spectral filtering of the SOA output degrades the signal quality, reducing the benefit offered by the SOA. However, narrow filters are required to reduce the crosstalk in high channel density systems. We characterize this tradeoff and find the optimum receiver bandwidth for varying channel spacing configurations in a spectrum-sliced wavelength-division multiplexed (WDM) system
Comparative study of spectrum-sliced incoherent light systems employing SOA-based noise suppression
No full textWe compare three SOA-based noise suppression approaches employed in spectrum-sliced WDM systems. Although the SOA at the transmitter provides best noise suppression, the SOA at the receiver may provide better value in last-mile access applications
Performance comparison of spectrum-slicing techniques employing SOA-based noise suppression at the transmitter or receiver
No full textWe compare three semiconductor optical amplifier (SOA)-based noise suppression approaches employed in incoherent light spectrum-sliced systems. Although the SOA at the transmitter provides the best absolute noise suppression, it is susceptible to performance degradation in the presence of optical filtering and dispersion. Using the SOA at the receiver can provide good performance while avoiding these limitations, and may provide better value in last-mile access applications
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
Feasibility study of SOA-based noise suppression for spectral amplitude coded OCDMA
Full text linkWe investigate the benefits of employing a saturated SOA to reduce optical noise in an incoherent light OCDMA system. In the context of spectrum-slicing, SOA-based noise suppression has shown significant potential for enhancing the signal quality of noisy light. In this paper, we evaluate the viability of the technique for spectral amplitude coded OCDMA, and show that the benefits of SOA-based noise suppression do not extend readily to this application, due to post-SOA optical filtering effects at the receiver. However, appreciable performance improvements can in principle be realized through optimized system and decoder design
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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