Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSingle-laser 32.5 Tbit/s Nyquist WDM transmission
463
0
0.0
(
0
)
Authors
David Hillerkuss
Ask ChatGPT about the research
No Arabic abstract
We demonstrate 32.5 Tbit/s 16QAM Nyquist WDM transmission over a total length of 227 km of SMF-28 without optical dispersion compensation. A number of 325 optical carriers are derived from a single laser and encoded with dual-polarization 16QAM data using sinc-shaped Nyquist pulses. As we use no guard bands, the carriers have a spacing of 12.5 GHz equal to the Nyquist bandwidth of the data. We achieve a high net spectral efficiency of 6.4 bit/s/Hz using a software-defined transmitter which generates the electrical modulator drive signals in real-time.
rate research
Read More
We review some currently discussed solutions for 400 Gbit/s inter-data center WDM transmission for up to 100 km. We focus on direct detected solutions, namely PAM4 and DMT, and present two WDM systems based on these formats.
A digraph is $m$-labelled if every arc is labelled by an integer in ${1, dots,m}$. Motivated by wavelength assignment for multicasts in optical networks, we introduce and study $n$-fibre colourings of labelled digraphs. These are colourings of the arcs of $D$ such that at each vertex $v$, and for each colour $alpha$, $in(v,alpha)+out(v,alpha)leq n$ with $in(v,alpha)$ the number of arcs coloured $alpha$ entering $v$ and $out(v,alpha)$ the number of labels $l$ such that there is at least one arc of label $l$ leaving $v$ and coloured with $alpha$. The problem is to find the minimum number of colours $lambda_n(D)$ such that the $m$-labelled digraph $D$ has an $n$-fibre colouring. In the particular case when $D$ is $1$-labelled, $lambda_1(D)$ is called the directed star arboricity of $D$, and is denoted by $dst(D)$. We first show that $dst(D)leq 2Delta^-(D)+1$, and conjecture that if $Delta^-(D)geq 2$, then $dst(D)leq 2Delta^-(D)$. We also prove that for a subcubic digraph $D$, then $dst(D)leq 3$, and that if $Delta^+(D), Delta^-(D)leq 2$, then $dst(D)leq 4$. Finally, we study $lambda_n(m,k)=max{lambda_n(D) tq D mbox{is $m$-labelled} et Delta^-(D)leq k}$. We show that if $mgeq n$, then $ds leftlceilfrac{m}{n}leftlceil frac{k}{n}rightrceil + frac{k}{n} rightrceilleq lambda_n(m,k) leqleftlceilfrac{m}{n}leftlceil frac{k}{n}rightrceil + frac{k}{n} rightrceil + C frac{m^2log k}{n}$ for some constant $C$. We conjecture that the lower bound should be the right value of $lambda_n(m,k)$.
Transmission of He-Ne (632 nm, 10 mW) Gaussian laser beam through Hexane and Water based magnetic nanofluids containing Fe3O4 nanoparticles show strong non-linear and magneto-optical effects. Application of external magnetic field (up to 1.7 Wb/m2) perpendicular to the incident laser beam produces a change in forward scattered pattern of the incident laser beam. Dependence of forward scattered patterns in presence of external magnetic field has been studied. Image processing has been carried out to understand spatial distribution of the forward scattered patterns and temporal evolution of patterns involving particle image velocimetry technique. Change in non-linear refractive index is estimated for samples showing self-diffraction arising from higher order non-linear optical effect. Observed effects are useful for understanding light scattering from magnetic nanofluids and developing optofluidic devices and sensors.
To date, no electro-optic platform enables devices with high bandwidth, small footprint, and low power consumption, while also enabling mass production. Here we demonstrate high-yield fabrication of high-speed graphene electro-absorption modulators using CVD-grown graphene. We minimize variation in device performance from graphene inhomogeneity over large area by engineering graphene-mode overlap and device capacitance to ensure high extinction ratio. We fabricate an 8 mm x 1 mm chip with 32 graphene electro-absorption modulators and measure 94% yield with bit error rate below the hard-decision forward error correction limit at 7 Gbits/s, amounting to a total aggregated data rate of 210 Gbits/s. Monte Carlo simulations show that data rates > 0.6 Tbits/s are within reach by further optimizing device cross-section, paving the way for graphene-based ultra-high data rate applications.
Quantum-dash (QD) mode-locked laser diodes (MLLD) lend themselves as chip-scale frequency comb generators for highly scalable wavelength-division multiplexing (WDM) links in future data-center, campus-area, or metropolitan networks. Driven by a simple DC current, the devices generate flat broadband frequency combs, containing tens of equidistant optical tones with line spacings of tens of GHz. Here we show that QD-MLLDs can not only be used as multi-wavelength light sources at a WDM transmitter, but also as multi-wavelength local oscillators (LO) for parallel coherent reception. In our experiments, we demonstrate transmission of an aggregate data rate of 4.1 Tbit/s (23x45 GBd PDM-QPSK) over 75 km standard single-mode fiber (SSMF). To the best of our knowledge, this represents the first demonstration of a coherent WDM link that relies on QD-MLLD both at the transmitter and the receiver.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
