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Based on the fundamental harmonic phase delay, a new definition of fundamental harmonic fractional delay (FHFD) is proposed to evaluate slow light with the consideration of signal distortion, to eliminate the dependence on the choice of the reference point. By solving the rate equation of erbium-doped fiber (EDF), it is shown that the slow light always accompanies the signal distortion when the periodic signal propagates in EDF, and FHFD depends on the signal distortion, as well as the average input power, the modulation depth and the length of EDF. The results of simulations and experiments indicate that the definition of FHFD is reasonable and effective to evaluate the slow light of periodic signals. [ABSTRACT FROM AUTHOR]

The temperature evolution of dielectric dispersion is examined for a coarse-grained BaTiO3 ceramic in the frequency range from 40 Hz to 1 GHz and over the temperature interval between −50°C and 80°C, which thus includes the orthorhombic-tetragonal phase transition and covers the large part of common usage temperature region. We find an important physical phenomenon that the phase transition has a notable influence on the microwave dielectric dispersion. The dielectric permittivity ε′ shows a maximum, whereas the characteristic frequency fr displays a minimum in the vicinity of orthorhombic-tetragonal phase transition temperature. Also, a large difference in the fr values is observed in the tetragonal phase between the heating process and the cooling process. It seems that the experimentally found phenomenon can be explained by the previously suggested mechanism of the emission of elastic shear waves from ferroelastic domain walls. [ABSTRACT FROM AUTHOR]

A compact in-line fiber-based polarization controller (FPC) made of a rotatable fiber squeezer is investigated in detail with the Mueller matrix model established based on the generalized principal state of polarization (PSP). The PSP caused by the fiber squeezing is in the equator plane, which turns around S3 axis on the Poincaré sphere when rotating the squeezer. Subsequently, a programmable polarization control method is proposed to realize the polarization conversion between arbitrary polarization states, in which only two parameters of phase shift and rotation angle need to be controlled. This type of FPC, which has a highly compact structure, lower insertion loss, and can be directly embedded into any fiber devices without any extra delay, will be an ideal PC for high-speed optical communication and all-optical signal processing. [ABSTRACT FROM AUTHOR]

Signal impairment is experimentally studied by using the extinction ratio (ER), error bit rate (BER) and optical spectrum in a three-cascaded semiconductor optical amplifier (SOA) setup. The signal with the ER of 13 dB and BER of <10-9 is achieved after the signal passing through the cascaded SOAs. With the results obtained from the experiment, we confirm that the three-cascaded SOAs used to compensate for power in the optical transmission can be accepted. This experimental result also offers the possibility of achieving a higher throughput of multiplane architecture by exploiting three switching domains instead of two switching domains in the energy-efficient design of a scalable optical multi-plane interconnection architecture. The space switches in output ports of multi-plane interconnection architecture can be improved to ?? = 32 × 32 × 32 = 32768. [ABSTRACT FROM AUTHOR]

We present an all-optical nonreturn-to-zero/return-to-zero (NRZ/RZ) to carrier-suppressed return-to-zero (CSRZ) format conversion scheme for differential phase-shift keying (DPSK) signals. The conversion is based on nonlinear polarization rotation of a semiconductor optical amplifier (SOA). The 4-channel NRZ-DPSK or RZ-DPSK signals at 10 Gb/s are simultaneously converted to the corresponding CSRZ-DPSK signals, with −0.8 and 1.4 dB average power penalties, respectively. Additionally, high quality format conversion performances are shown with the optical spectra and eye diagrams. [ABSTRACT FROM AUTHOR]

The interaction between two single-stranded DNA (ssDNA) molecules as pairing to a double-stranded DNA (dsDNA) molecule is studied by the reflectometric interference spectroscopy (RIFS) technology. A nano-porous anode alumina membrane coated an Au layer is employed as the sensor substrate. The results indicate that when there are mismatched nucleotide bases, the effective optical thicknesses (OTeff) have obvious difference, and the changes of OTeff are connected with the sensor layer thickness and the effective refractive index. It is also demonstrated that the RIFS technique can be used to precisely detect the ssDNA molecules with individual base mismatched as pairing to dsDNA. [ABSTRACT FROM AUTHOR]

Broad-band all-optical wavelength conversion of differential phase-shift keyed (DPSK) signal is experimentally demonstrated. This scheme is composed of a one-bit delay interferometer demodulation stage followed by a semiconductor optical amplifier (SOA) based nonlinear polarization switch. A wavelength converter for the 10 Gb/s DPSK signal is presented, which has a wide wavelength range of more than 30 nm. The converted signals experience small power penalties less than 1.4 dB compared with the original signal, at a bit error rate of 10−9. Additionally, the optical spectra, the measured waveforms and the open eye diagrams of the converted signals show a high quality wavelength conversion performance. [ABSTRACT FROM AUTHOR]

We report a systematic method to perform calculations of spectral line broadening parameters in plasmas. This method is applied to calculate Stark-broadening line profiles of Pα (n = 4 → n = 3) transitions under certain specific plasma conditions, by treating this case as an example. In the framework of the fully relativistic Dirac R-matrix theory, we calculate the electron-impact broadening operators, which are assumed to be diagonal matrix to simplify the situation. The electric microfield distribution function is calculated by retaining Hooper's formalism. The dipole matrix elements and atomic structure parameters used in these calculations have been obtained from atomic structure GRASP code. Based on this required data, we calculate the Stark-broadened line profiles of the Paschen spectral lines in He II ions in a systematic manner. Overall, there is a very good agreement between our calculated Stark-broadened line profiles and other line broadening numerical simulation codes (SimU and MELS). Our reported spectral line-broadening data have real applications in plasma spectroscopy, plasma diagnosis and also play a fundamental role in plasma modeling. [ABSTRACT FROM AUTHOR]

A cellular automaton model is proposed to consider the anticipation effect in drivers' behavior. It is shown that the anticipation effect can be one of the origins of synchronized traffic flow. With anticipation effect, the congested traffic flow simulated by the model exhibits the features of synchronized flow. The spatiotemporal patterns induced by an on-ramp are also consistent with the three-phase traffic theory. Since the origin of synchronized flow is still controversial, our work can shed some light on the mechanism of synchronized flow. [ABSTRACT FROM AUTHOR]