Benzyl alcohol is oxidized selectively to benzaldehyde with high yield, with a little formation of benzylbenzoate, by molecular oxygen over a reusable nano-size gold catalyst supported on U 3 O 8 , MgO, Al 2 O 3 or ZrO 2 in the absence of any solvent.Liquid phase oxidation of benzyl alcohol is an important preferred reaction practically for the production of chlorine-free benzaldehyde, without loss of carbon in the form of CO 2 (a geenhouse gas). The preparation of benzaldehyde by reacting benzyl alcohol with stoichiometric or excess amounts of potassium or ammonium permanganate in aqueous acidic medium 1 is not environmentally benign at all, because of the formation of a large amount of toxic waste. A few studies on the benzyl alcoholto-benzaldehyde oxidation by H 2 O 2 or O 2 in the presence of organic solvent, using different solid catalysts, such as Pd/C, 2 Pd(II) hydrotalcite, 3 Pd-Ag/pumice, 4 Ru-Co-Al hydrotalcite, 5 Ni-containing hydrotalcite 6,7 and nano-size NiO 2, 8 have been

Transmission of a 73.7 Tb/s (96x3x256-Gb/s) DP-16QAM mode-division-multiplexed signal over 119km of few-mode fiber transmission line incorporating an inline multi mode EDFA and a phase plate based mode (de-)multiplexer is demonstrated. Data-aided 6x6 MIMO digital signal processing was used to demodulate the signal. The total demonstrated net capacity, taking into account 20% of FEC-overhead and 7.5% additional overhead (Ethernet and training sequences), is 57.6 Tb/s, corresponding to a spectral efficiency of 12 bits/s/Hz. ©2012 Optical Society of America

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We present the first demonstration of a multimode (two mode-group) erbium-doped fiber amplifier for Space Division Multiplexed (SDM) applications and demonstrate various design and performance features of such devices. In particular we experimentally demonstrate that differential modal gains can be controlled and reduced both by fiber design and control of the pump field distribution. Using a suitably designed fiber we demonstrate simultaneous modal gains of ~20 dB for different pair-wise combinations of spatial and polarization modes in an EDFA supporting amplification of 6 distinct modes.

A compact upconversion fiber laser operating around 810 nm is proposed using thulium-doped silica-based fiber with locally modified thulium environment by high alumina codoping. Using a comprehensive numerical model of thulium doped fiber we investigate performance of the proposed laser. Comparison with two other thulium hosts, fluoride glass and standard silica, is presented. Efficient lasing can be expected even for silica based fiber for specific ranges of the fiber and laser cavity parameters, especially when 3H4 lifetime is enhanced. With moderate pump power of 5 W at wavelength of 1064 nm, the predicted output power of the upconversion laser is about 2 W at 810 nm.

Transmission of a 73.7 Tb/s (96x3x256-Gb/s) DP-16QAM mode-division-multiplexed signal over 119km of few-mode fiber transmission line incorporating an inline multi mode EDFA and a phase plate based mode (de-)multiplexer is demonstrated. Data-aided 6x6 MIMO digital signal processing was used to demodulate the signal. The total demonstrated net capacity, taking into account 20% of FEC-overhead and 7.5% additional overhead (Ethernet and training sequences), is 57.6 Tb/s, corresponding to a spectral efficiency of 12 bits/s/Hz. ©2012 Optical Society of America

The porous core layer deposited by modified chemical vapour deposition process has been analyzed in terms of thickness, pore size distribution, homogeneity and characteristics of the soot particles to investigate their variation with deposition temperature and input vapour composition. The compositions selected were SiO(2), SiO(2)-GeO(2) and SiO(2)-P(2)O(5). Rare earth ions were incorporated into the deposit by a solution doping technique. The analysis of deposited microstructures was found to provide a quantitative indication about the rare earth incorporation and its variation with respect to process conditions. Thus the characterization provides a method of controlling rare earth doping and ultimate preform/fiber properties.

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