Bit-error probability for direct detection of optical RZ signal degraded by ASE noise and timing jitter

We analyze theoretically the interplay between optical return-to-zero signal degradation due to timing jitter and additive amplified-spontaneous-emission noise. The impact of these two factors on the performance of a square-law direct detection receiver is also investigated. We derive an analytical expression for the bit-error probability and quantitatively determine the conditions when the contributions of the effects of timing jitter and additive noise to the bit error rate can be treated separately. The analysis of patterning effects is also presented. © 2007 IEEE.

Effect of carrier reshaping and narrow MUX-DEMUX filtering in 0.8 bit/s/Hz WDM RZ-DPSK transmission

Effect of the carrier shape in the ultra high dense wavelength division multiplexing (WDM) return to zero differential phase shift keying (RZ-DPSK) transmission has been examined through numerical optimization of the pulse form, duty cycle and narrow multiplex/de-multiplex (MUX/DEMUX) filtering parameters. © 2007 Springer Science+Business Media, LLC.

Service employee clusters in banking:exploring Ind's typology considering behaviour, commitment and attitude about leadership

Purpose: Ind suggests front line employees can be segmented according to their level of brand-supporting performance. His employee typology has not been empirically tested. The paper aims to explore front line employee performance in retail banking, and profile employee types. Design/methodology/approach: Attitudinal and demographic data from a sample of 404 front line service employees in a leading Irish bank informs a typology of service employees. Findings: Champions, Outsiders and Disruptors exist within retail banking. The authors provide an employee profile for each employee type. They found Champions amongst males, and older employees. The highest proportion of female employees surveyed were Outsiders. Disruptors were more likely to complain, and rated their performance lower than any other employee type. Contrary to extant literature, Disruptors were more likely to hold a permanent contract than other employee types. Originality/value: The authors augment the literature by providing insights about the profile of three employee types: Brand Champions, Outsiders and Disruptors. Moreover, the authors postulate the influence of leadership and commitment on each employee type. The cluster profiles raise important questions for hiring, training and rewarding front line banking employees. The authors also provide guidelines for managers to encourage Champions, and curtail Disruptors. © Emerald Group Publishing Limited.

Building bank brands:how leadership behavior influences employee commitment

Front line employees are critical to service brand success, as their performance brings brand promises to life. Banking employees, like others, must remain committed to their employers, to live the brand, particularly during periods of economic uncertainty and customer frustration. Employees' commitment influences their brand adoption and brand-supporting behavior during service encounters. Effective leadership fosters employee commitment and brand supporting behaviors. This study examines the nature of employee commitment in banking, distinguishing between affective, continuance and normative commitment. The study explores bank leaders, examining whether initiating structure leader behavior or considerate leader behavior is most effective in encouraging employee commitment. Data from a sample of 438 employees in a leading Irish bank reveals the optimal leadership style for employee commitment. © 2012 Elsevier Inc.

Design of FBG-based ultra-narrow asymmetric filter for transmission with 0.8 bit/s/Hz spectral efficiency without polarisation multiplexing

We propose a novel approach to ultra-narrow optical filtering based on a specially designed slightly asymmetric filter, which can be fabricated using fibre Bragg gratings. A feasibility of 8×40 Gbit/s DWDM RZ transmission with 0.8 bit/s/Hz spectral efficiency (without polarisation multiplexing) over 1280 km of SMF/DCF link without FEC has been confirmed by numerical modelling. © 2004 Elsevier Inc. All rights reserved.

Comparison of bit error rate estimation methods for QPSK CO-OFDM transmission

In this letter, we experimentally study the statistical properties of a received QPSK modulated signal and compare various bit error rate (BER) estimation methods for coherent optical orthogonal frequency division multiplexing transmission. We show that the statistical BER estimation method based on the probability density function of the received QPSK symbols offers the most accurate estimate of the system performance.

Reduction of nonlinear intrachannel effects by channel asymmetry in transmission lines with strong bit overlapping

We have examined the statistics of simulated bit-error rates in optical transmission systems with strong patterning effects and have found strong correlation between the probability of marks in a pseudorandom pattern and the error-free transmission distance. We discuss how a reduced density of marks can be achieved by preencoding optical data.

Calculation of non-Gaussian statistics and bit error rate degradation due to pulse-to-pulse interaction

We develop a theoretical method to calculate jitter statistics of interacting solitons. Applying this approach, we have derived the non-Gaussian probability density function and calculated the bit-error rate as a function of noise level, initial separation and phase difference between solitons.

Bit error rate estimation methods for QPSK CO-OFDM transmission

Coherent optical orthogonal frequency division multiplexing (CO-OFDM) is an attractive transmission technique to virtually eliminate intersymbol interference caused by chromatic dispersion and polarization-mode dispersion. Design, development, and operation of CO-OFDM systems require simple, efficient, and reliable methods of their performance evaluation. In this paper, we demonstrate an accurate bit error rate estimation method for QPSK CO-OFDM transmission based on the probability density function of the received QPSK symbols. By comparing with other known approaches, including data-aided and nondata-aided error vector magnitude, we show that the proposed method offers the most accurate estimate of the system performance for both single channel and wavelength division multiplexing QPSK CO-OFDM transmission systems. © 2014 IEEE.

Time resolved bit error rate analysis of a fast switching tunable laser for use in optically switched networks

We investigate the use of different direct detection modulation formats in a wavelength switched optical network. We find the minimum time it takes a tunable sampled grating distributed Bragg reflector laser to recover after switching from one wavelength channel to another for different modulation formats. The recovery time is investigated utilizing a field programmable gate array which operates as a time resolved bit error rate detector. The detector offers 93 ps resolution operating at 10.7 Gb/s and allows for all the data received to contribute to the measurement, allowing low bit error rates to be measured at high speed. The recovery times for 10.7 Gb/s non-return-to-zero on–off keyed modulation, 10.7 Gb/s differentially phase shift keyed signal and 21.4 Gb/s differentially quadrature phase shift keyed formats can be as low as 4 ns, 7 ns and 40 ns, respectively. The time resolved phase noise associated with laser settling is simultaneously measured for 21.4 Gb/s differentially quadrature phase shift keyed data and it shows that the phase noise coupled with frequency error is the primary limitation on transmitting immediately after a laser switching event.

Bit-error rate performance of 20 Gbit/s WDM RZ-DPSK non-slope matched submarine transmission systems

Applying direct error counting, we assess the performance of 20 Gbit/s wavelength-division multiplexing return-to-zero differential phase-shift keying (RZ-DPSK) transmission at 0.4 bit/(s Hz) spectral efficiency for application on installed non-zero dispersion-shifted fibre based transoceanic submarine systems. The impact of the pulse duty cycle on the system performance is investigated and the reliability of the existing theoretical approaches to the BER estimation for the RZ-DPSK format is discussed.

Externalizing, internalizing and fostering commitment:the case of born-global firms in emerging economies

This paper examines the HR practices of mature born-global firms from 29 emerging economies. Through an examination of large scale survey data the paper questions the extent to which firm size impacts the employment of temporary workers, the employment of skilled workers and the extent of employee training. Findings suggest that as firm size increases the use of temporary workers decreases, the number of skilled workers increases and the number of employees receiving training also increases. The paper highlights how born-global firms are able to shift away from externalized, market-based approaches towards more internalized, commitment-based approaches in order to survive, adapt and grow.

Corporate social responsibility and organizational commitment:the moderating role of individuals’ attitudes to CSR

Corporate Social Responsibility (CSR) becomes ever more important for organizations. In times of corporate scandals and more governmental regulation on the one hand and a foreseeable shortage of highly qualified employees on the other, CSR is both a means to serve the wider society and to attract employees with a positive reputation and image. The aim of the present study was to determine whether CSR activities as perceived by employees indeed lead to more employee affective commitment and whether this would be moderated by employee differences in importance of CSR. The study differentiated two forms of CSR, namely corporate social responsibility directed towards individual employees (CSR-E) and directed towards the wider society (CSR-S). We surveyed 89 employees and found evidence for the predicted moderation and for both forms of CSR such that CSR-E and CSR-S and affective commitment were only positively related for those employees who evaluated CSR as important. Implications for recruitment and future research are discussed.