1.6 Tbit/s (40/spl times/40 Gbit/s) DPSK transmission over 3/spl times/100 km of TeraLight fibre with direct detection

By transmitting 40 channels over 300 km of TeraLight fibre, it is shown that optical differential phase shift keying can be used in 100 GHz-spaced 40 Gbit/s systems, with direct detection and a simple receiving filter. Chromatic dispersion tolerance around 300 ps/nm is also measured, compared to 70 ps/nm for NRZ.     

Intercalation of a pendant-arm tetraazamacrocycle into molybdenum disulfide

A novel macrocycle-MoS2 nanocomposite has been synthesized and characterized using the exfoliation/restacking properties of LiMoS2, providing the first of a new family of intercalation compounds.     

3.2 Tbit/s (80 × 40 Gbit/s) phase-shaped binary transmissionover 3 × 100 km with 0.8 bit/s/Hz efficiency

50 GHz-spaced 80 × 40 Gbit/s WDM transmission over 300 km of TeraLight^TM fibre is demonstrated without polarisation demultiplexing, using the PSBT format. A record capacity of 3.2 Tbit/s is thus achieved over the C-band only, with a spectral efficiency of 0.8 bit/s/Hz     

Highly sensitive 565 Mb/s DPSK heterodyne transmission experiment using direct current modulation of a DFB laser transmitter

A comparison between external phase modulation and phase modulation obtained through direct current modulation of a multiquantum-well distributed feedback (DFB) transmitter is reported for a sensitive 565 Mb/s differential-phase-shift-keying (DPSK) heterodyne transmission experiment. A limited sensitivity penalty for direct phase modulation is expected from the driving current pulse shape, the transmitter FM response and the receiver characteristics. The experimentally observed 0.5 dB penalty is in agreement with theory and highlights the potential of direct DPSK modulation as compared to both standard DPSK and continuous-phase frequency shift keying (CPFSK) schemes.<>     

Synthesis and characterization of poly(ethylene glycol amine) electrolytes and nanocomposites based on graphite

Poly(ethylene glycol) functionalized with an amino group (PEG-amine) was synthesized and characterized by proton NMR and FTIR spectroscopy. The polymer was complexed with lithium triflate (LiOTf) in varying ratios, and it was found that the composition (PEG-amine)_8.0LiOTf exhibited a maximum ionic conductivity of 10^?5 S/cm at a temperature of 320 K. Graphite platelets were also dispersed into the polymer matrix, and the resulting nanomaterials were shown to be electrically conductive, with a maximum value of 1 × 10³ S/cm when the graphite is present at 50% by mass.     

1.31-1.55-/spl mu/m phased-array demultiplexer on InP

The first demultiplexers on InP at 1.31-1.55 /spl mu/m based on low-order waveguide arrays have been fabricated and characterized. We show the calculated and measured spectral responses of two devices with 6 and 10 waveguides in the grating. The on-chip loss of the devices is 4.5 dB and the crosstalks are down to -25 dB. Thanks to their large bandwidth, the devices are polarization insensitive and no strong influence of the temperature is seen.     

Encapsulation of polyanilines into graphite oxide

Herein we report on the intercalation of polyaniline, poly(2-ethylaniline), and poly(2-propylaniline) into graphite oxide. This was achieved by taking advantage of the exfoliation/reconstruction properties of the layered host. The resulting intercalates were characterized by powder X-ray diffraction and thermogravimetric analysis.     

Development of Ferromagnetic Materials Containing Co2P,Fe2P Phases from Organometallic Dendrimers Precursors

The development of synthesis methods to access advanced materials, such as magnetic materials that combine multimetallic phosphide phases, remains a worthy research challenge. The most widely used strategies for the synthesis of magnetic transition metal phosphides (TMPs) are organometallic approaches. In this study, Fe-containing homometallic dendrimers and Fe/Co-containing heterometallic dendrimers were used to synthesize magnetic materials containing multimetallic phosphide phases. The crystalline nature of the nearly aggregated particles was indicated for both designed magnetic samples. In contrast to heterometallic samples, homometallic samples showed dendritic effects on their magnetic properties. Specifically, saturation magnetization (M_s) and coercivity (H_c) decrease as dendritic generation increases. Incorporating cobalt into the homometallic dendrimers to prepare the heterometallic dendrimers markedly increases the magnetic properties of the magnetic materials from 60 to 75 emu/g. Ferromagnetism in homometallic and heterometallic particles shows different responses to temperature changes. For example, heterometallic samples were less sensitive to temperature changes due to the presence of Co₂P in contrast to the homometallic ones, which show an abrupt change in their slopes at a temperature close to 209 K, which appears to be related to the Fe₂P ratios. This study presents dendrimers as a new type of precursor for the assembly of magnetic materials containing a mixture of iron- and cobalt-phosphides phases with tunable magnetism, and provides an opportunity to understand magnetism in such materials.     

Ridge laser with spot-size converter in a single epitaxial step forhigh coupling efficiency to single-mode fibers

We report on a 1.55-μm InGaAsP MQW laser diode with an integrated spot-size converter fabricated in a single epitaxial step using conventional photolithography. The laser structure uses a conventional ridge guide for the active layers and a second larger ridge for the passive waveguide. Low-beam divergence of typically 9°×9° results in about 3-dB coupling losses, with a cleaved optical fiber     

Effects of hole burning, carrier-induced losses and thecarrier-dependent differential gain on the static characteristics of DFBlasers

A model solving the steady-state laser equations above threshold is presented. It calculates important laser parameters such as the threshold losses, emitted optical power, gain margin between the main and secondary modes and, spectral linewidth of any index-grating DFB laser structure. A more exact theoretical linewidth calculation considering nonuniform carrier densities and gain saturation is reported. Good agreement with experiments is found on phase-shifted lasers. The model is used to investigate the factors that determine the importance of spatial hole burning, and general design rules are proposed to reduce this effect. Gain compression combined with carrier-dependent losses is shown to limit the differential external efficiency and cause the emission wavelength to decrease and the spectral linewidth to rebroaden at high output power