Wavelength-division multiplexing

About: Wavelength-division multiplexing is a research topic. Over the lifetime, 25059 publications have been published within this topic receiving 332027 citations. The topic is also known as: WDM.

Analysis of optical crosstalk effects in multi-wavelength switched networks

Abstract: Two optical crosstalk mechanisms, homo- and hetero-wavelength crosstalk, are identified in multi-wavelength switched networks. Homo-wavelength crosstalk does not arise in point-point systems and is a significant factor in multi-wavelength network design. A new signal dependent statistical model was used to evaluate the crosstalk effects due to non-ideal filtering in an established multi-wavelength transport network architecture. The authors find that the optical filters used in this network must have an adjacent channel rejection of /spl ges/20 dB in order to achieve the system design target of 622 Mbit/s channel base rate, at 10/sup /spl minus/10/ BER with 1 dB crosstalk penalty through 10 nodes. >

Pulse-Shaping With Digital, Electrical, and Optical Filters—A Comparison

Abstract: We investigate the performance of sinc-shaped QPSK signal pulses generated in the digital, electrical, and optical domains. To this end an advanced transmitter with a digital pulse-shaper is compared to analog transmitters relying on pulse-shaping with electrical and optical filters, respectively. The signal quality is assessed within a single carrier setup as well as within an ultra-densely spaced WDM arrangement comprising three channels. An advanced receiver providing additional digital filtering with an adaptive equalization algorithm to approximate an ideal brick-wall Nyquist filter has been used for all schemes. It is found that at lower symbol rates, where digital processing is still feasible, digital filters with a large number of filter coefficients provide the best performance. However, transmitters equipped with only electrical or optical pulse-shapers already outperform transmitters sending plain unshaped NRZ signals, so that for higher symbol rates analog electrical and optical techniques not only save costs, but are the only adequate solution.

Few-Mode Erbium-Doped Fiber Amplifiers: A Review

Abstract: Space-division multiplexing has brought a fresh perspective to the optical fiber community over the last three years and many global players around the world have been involved with both the theoretical and the experimental questions raised by this promising approach. If this technology is to be introduced in the future optical fiber networks, this implies that most of the optical components of the transmission line, including the popular Erbium-doped fiber amplifiers that lie at the heart of fiber communications need to be reexamined. This study reviews the way the new generation of Erbium-doped fibers affects the recent findings on few-mode fibers and how they may further play a central role in the deployment of this technology.

An algebraic approach to the unequal-spaced channel-allocation problem in WDM lightwave systems

Abstract: To reduce four-wave-mixing crosstalk in high-capacity, long-haul, repeaterless, wavelength-division multiplexing (WDM) lightwave systems, the use of unequally spaced channels has been proposed. Instead of being solved by integer linear programming, the unequal-spaced channel-allocation problem is treated by constructing suitable optical orthogonal codes in optical code-division multiple-access (CDMA). An "algebraic" framework and three algorithms on finding the frequency locations of unequally spaced WDM channels are introduced, where the constructions are based on generating optical CDMA codewords with a predetermined pulse separation and "aperiodic" autocorrelation sidelobes no greater than one. The algorithms potentially provide a fast and simple alternative to solve the problem, besides the proposed computer-search method.

Optical duobinary transmission system featuring improved receiver sensitivity and reduced optical bandwidth

Abstract: We propose and demonstrate a simple method to improve both the receiver sensitivity and spectral efficiency of the optical duobinary transmission system. Compared to the conventional duobinary signal generated by using an electrical low-pass filter, more than 1-dB improvement of receiver sensitivity and /spl sim/20% reduction in the spectral width are achieved simply by filtering the 10-Gb/s duobinary signals with a narrow-bandwidth (7 GHz) optical filter.