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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.


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01 Jun 2011
TL;DR: In this paper, the authors showed a 16x525 Gb/s coherent optical OFDM transmission over 4,160 km of SSMF with 50-GHz channel spacing using MIMO processing.
Abstract: We show 16x525 Gb/s (40 Gb/s after coding) coherent optical OFDM transmission over 4,160 km of SSMF with 50-GHz channel spacing MIMO-processing in the receiver enables polarization de-multiplexing and a large PMD tolerance Introduction Polarization multiplexing (POLMUX) is a very effective method to double the spectral efficiency of a transmission system [1] Direct-detected POLMUX however has a reduced tolerance to polarization mode dispersion (PMD), because the polarization demultiplexing introduces crosstalk between the polarization tributaries [2] In [3] it has been shown that in combination with coherent detection, POLMUX can effectively be described as a polarization multiple-input multiple-output (MIMO) system in which any space time coding algorithm can be applied This has enabled the demonstration of various singlecarrier MIMO experiments with bit rates up to 111-Gb/s and a superior tolerance towards chromatic dispersion and PMD [4] OFDM presents an alternative to digital coherent systems that inherently offers a virtually unlimited chromatic dispersion [5] and PMD [6] tolerance and is furthermore easier scalable to higher level modulation formats [7] It has therefore recently received considerable interest in the fiber-optic community However, all fiber-optic OFDM experiments reported so far employed only a single wavelength and one polarization of the optical fiber In this paper, we report for the first time POLMUX coherent optical OFDM (POLMUX-CO-OFDM) transmission enabled by MIMO processing Transmission of 16x525-Gb/s POLMUX-CO-OFDM channels at 50-GHz WDM spacing is achieved over 4,160-km SSMF with large amounts of PMD Experimental setup The experimental setup is shown in Fig 1 At the transmitter, the output of 16 ECL lasers (100-kHz linewidth), aligned on a 50-GHz ITU grid between 15513 nm and 15574 nm, are modulated using two parallel modulator structures for separate modulation of the even and odd channels Each modulator structure consists of two single-ended MZM modulators to modulate each polarization independently Subsequently the two POLMUX signals are combined using a polarization beam splitter and the even and odd WDM channels are combined with a 50-GHz interleaver The electrical OFDM channel allocation is illustrated in Fig 1 The 525-Gb/s OFDM signal consists of two polarizationmultiplexed subcarrier-multiplexed OFDM bands, so in total four 131-Gb/s tributaries The FFT size is 256, from which 168 channels carry data QPSK modulation is used for symbol mapping and the cyclic prefix is 4-ns (40 samples) per OFDM symbol The baseband generation and IQ-mixing is discussed in detail in [5] As illustrated in Fig 1, the interleaver is aligned such that the image band is rejected The re-circulating loop consists of 4 spans of 80-km SSMF without optical dispersion compensation After every span, amplification is provided by a Raman/EDFA structure with an average on/off Raman gain of ~6 dB The optimum launch power was -7 dBm/ch A dynamic gain equalizer (DGE) is used for power equalization and a loop-synchronous polarization scrambler (LSPS) is employed to reduce loop-induced polarization effects A polarization maintaining fiber with a differential group delay (DGD) of 86-ps is added to the re-circulating loop After 13 roundtrips this emulates a ~300-ps average PMD At the receiver, the signal is split in two random polarizations and detected with a polarizationdiversity heterodyne receiver An ECL with ~100-kHz linewidth is used as free running local oscillator (LO) Subsequently, a real-time digital storage oscilloscope (DSO) is used to sample the two outputs of the heterodyne receiver The bandwidth of the DSO is 16 GHz and the sampling frequency is 50 GHz The data is then post-processed off-line Figure 1: Experimental setup, with LD: laser diode, AWG: arrayed waveguide grating, MZ: Mach Zehnder, PBS: polarization beam splitter, LO: local oscillator, CP: cyclic prefix, TS: training symbol ~~

69 citations

Journal ArticleDOI
TL;DR: One spectral-amplitude-coding (SAC) scheme combined with wavelength-division-multiplexing (WDM) is proposed for optical code-division multiple-access systems, which has better performance against the effect of the phase-induced intensity noise arising in the photodetecting process.
Abstract: One spectral-amplitude-coding (SAC) scheme combined with wavelength-division-multiplexing (WDM) is proposed for optical code-division multiple-access systems. The supported code length is more flexible than the previous SAC codes and the corresponding encoder-decoder requires less fiber gratings, thus, the system becomes cheap and simple. As compared to the conventional SAC systems, this WDM/SAC system not only reserves the interference-cancellation property, but also has better performance against the effect of the phase-induced intensity noise arising in the photodetecting process. Thus, a larger number of active users can be supported under a given bit-error rate.

69 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the energy efficiency of optical OFDM-based networks and proposed a mixed integer linear programming model to minimize the total power consumption of rate and modulation adaptive OFDM networks.
Abstract: Orthogonal frequency-division multiplexing (OFDM) has been proposed as an enabling technique for elastic optical networks to support heterogeneous traffic demands by enabling rate and modulation adaptive bandwidth allocation. The authors investigate the energy efficiency of optical OFDM-based networks. A mixed integer linear programming model is developed to minimise the total power consumption of rate and modulation adaptive optical OFDM networks. Considering a symmetric traffic, the results show that optical OFDM-based networks can save up to 31% of the total network power consumption compared to conventional Internet protocol over wavelength division multiplexing (WDM) networks. Considering the power consumption of the optical layer, the optical OFDM-based network saves up to 55% of the optical layer power consumption. The results also show that under an asymmetric traffic scenario, where more traffic is destined to or originates from popular nodes, for example data centres, the power savings achieved by the optical OFDM-based networks are limited as the higher traffic demands to and from data centres reduce the bandwidth wastage associated with conventional WDM networks. Furthermore, the achievable power savings through data compression have been investigated, considering an optical OFDM-based network.

69 citations

Journal ArticleDOI
TL;DR: In this paper, the authors presented a high-speed four-level pulse amplitude modulation at 25 GBd of a 1.5 μ m vertical-cavity surface-emitting laser (VCSEL).
Abstract: Current short-range optical interconnects capacity is moving from 100 to 400 Gb/s and beyond. Direct modulation of several laser sources is used to minimize bandwidth limitations of current optical and electrical components. This total capacity is provided either by wavelength division multiplexing or parallel optics; it is important to investigate on the ultimate transmission capabilities of each laser source to facilitate current capacity standards and allow for future demands. High-speed four-level pulse amplitude modulation at 25 GBd of a 1.5 μ m vertical-cavity surface-emitting laser (VCSEL) is presented in this paper. The 20 GHz 3 dB-bandwidth laser is, at the time of submission, the largest bandwidth of a 1.5 μ m VCSEL ever reported. Forward error correction (FEC) is implemented to achieve transmission over 100 m virtually error free after FEC decoding. Line rate of 100 Gb/s is achieved by emulation polarization multiplexing using 50 Gb/s signal obtained from a single VCSEL.

69 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023343
2022689
2021479
2020626
2019693
2018725