Use of 1-m Bi2O3 nonlinear fiber for 160-Gbit/s optical time-division demultiplexing based on polarization rotation and a wavelength shift induced by cross-phase modulation

We present, for the first time to our knowledge, experimental results of the use of a 1-m-long Bi2O3-based nonlinear fiber (Bi-NLF) with a nonlinear parameter gamma of approximately 1100 W(-1) km(-l) within an all-fiber-based 160Gbit/s optical time-division multiplexing (OTDM) data demultiplexer. Our demultiplexing switch basically uses the principle of the Kerr shutter, and its switching performance is further enhanced by the additional use of the wavelength blueshift of data pulses, which is induced by cross-phase modulation from the control pulse's trailing edge. The OTDM demultiplexer, composed of the 1-m Bi-NLF, readily achieves error-free demultiplexing operation of all 16 channels.     

Effect of dispersion on the relaxation-retardation time scale ratio

A simple relation between relaxation (modulus) and retardation (permittivity and compliance) times is determined for cases of dispersive instead of purely exponential response functions. An analytical solution for the Cole-Cole case and numerical treatments of the Cole-Davidson function reveal that the ratio of the relaxation- to retardation time constant is given by the ratio of the high- to low-frequency dielectric constant raised to the power of 1x, where x is the exponent that gauges the deviation from exponentiality.     

A new synthesis of thioketones from hydrazones and disulfur dichloride

Reaction of ketone hydrazones with disulfur dichloride in the presence of triethylamine in benzene at 0 °C - room temperature afforded the corresponding thiones in a moderate to high yield, probably via thioxothioketone (R₂C=S=S) intermediate.     

Photoregulated binding ability of azoaromatic polymer for surfactant

Water-soluble polymeric azodyes containing an azobenzene moiety in their side chain, p-phenylazoacrylanilide (PAAn)–acrylamide (AAm) copolymers, were synthesized and the adsorption-desorption behavior of sodium dodecyl sulfate (SDS) onto these copolymers in water was investigated by means of conductivity measurements, with attention to the hydrophobicity of the copolymer. The conductivity of the PAAn-AAm copolymer/SDS complex aqueous solution decreased with increasing PAAn composition in the copolymer. This result indicates that the SDS molecules adsorbed onto the copolymer. The adsorption state of SDS molecules on the copolymer was considered to take a micellelike form. When the hydrophobicity of the PAAn-AAm copolymer was decreased by means of the photoisomerization of an azodye moiety, the conductivity of the PAAn-AAm copolymer/SDS aqueous solution increased. This phenomenon can be explained as a result of desorption of SDS molecules from the copolymer. When the light source was cut off, the conductivity took on its original value. This indicated that SDS was desorbed by the photochemical trans to cis and adsorbed by cis to trans isomerization of the PAAn moiety.     

Isolation and characterization of some very stable 1-phospha-allenes: sterically protected iminomethylene- and ethenylidenephosphines

Very stable iminomethylenephosphine (3) and ethenylidenephosphine (4) were obtained by steric protection with the 2,4,6-tri-tertbutylphenyl group and some of the spectroscopic data are described.