Multipath-induced pulse broadening in a non-line-of-sight (NLOS) optical scattering channel is investigated. Expressions for impulse response and digital signal-to-noise ratio (DSNR) penalty induced by intersymbol interference (ISI) of a NLOS ultraviolet (UV) scattering communication are introduced based on a single-scattering model, and simulated results for some typical atmospheric condition and configuration of geometry are given in the paper. It is shown that the multipath dispersion is one of the most important factors limiting the system performances, and return-to-zero (RZ) format is more suitable for the optical scattering communications than non-return-to-zero (NRZ) format. The method proposed here can be used to predict available bandwidth and data rate of the communication system operating in a NLOS optical scattering channel.

By using one-dimensional self-consistent relativistic fluid model, a novel type of moving relativistic electromagnetic solitons with high intensity in electron-ion plasmas where the ion dynamics is taken into account is investigated numerically. Unlike solitons with single-humped scalar potential found in previous studies, these solitons possess multi-humped scalar and vector potential. The existence of such soliton solutions is investigated in plasmas with different background densities, and the properties of these solitons are presented in detail. We found that the peculiar profile of electron density has alternating regions of humps and dips like a Bragg grating.

By using the amplified 10-GHz, 5.5-ps sech2 pulses with high quality and chirp-free from regeneratively mode-locked fiber laser (RMLFL) as the soliton source, 2-5 order optical soliton phenomena are observed successfully in a 4.28-km dispersion flattened fiber. The experimental results agree well with the theoretical calculation.

A couple of simple-structure phase modulators were used in active mode-locked fiber laser to implement repetition rate continuous tuning. The laser produces pulse as short as 5.7 ps whose repetition rate tuning can cover the spacing of the adjoining order mode-locking frequencies.

The modulation instability of quasi-plane-wave optical beams is investigated in the frame of generalized Schrodinger equation with the nonlinear term of a general form. General expressions are derived for the dispersion relation, the critical transverse spatial frequency, as well as the instability growth rate. The analysis generalizes the known results reported previously. A detailed discussion on the modulation instability in biased centrosymmetric photorefractive media is also given.

In an open /\ type system with the spontaneously generated coherence (SGC), when the probe and driving fields have different frequencies, the switching of the group velocity of the probe pulse from subluminal to superluminal is realized not only by adjusting values of the relative phase between the probe and driving fields but also by varying values of the incoherent pumping rate. For the subluminal propagation, the system always exhibits the probe absorption, however, the superluminal propagation is always companied with gain of the probe field.

Statistical distributing and magnitude of the first and second-order polarization mode dispersion (PMD) vectors are evaluated and the timing displacements of its effects on dispersion-managed soliton (DMS) are also given with help of coarse-step approach, such as Jones matrix (JME) and coupled nonlinear Schrodinger equations (CNLSE). The results showed that the coarse-step approach can not only simulate the statistical characteristics of PMD, but also compute the nonlinear pulse characteristic of timing and energy jitters evolution affected by PMD. The presented results are very useful to simplify the measurement of second-order PMD and instructively reveal the degree of PMD effects in DMS systems.

We have observed a hole in the absorption profile of the homogeneously broadened absorption band of an Alexandrite crystal. With the spectral hole-burning technique that resulting from the periodic modulation of the ground state population at the beat frequency between the pump and the probe fields, we observed the slowdown the light propagation with the group velocity as slow as 12.5 m/s at room temperature. And the group velocity in the Alexandrite crystal depends on the amplitude modulation frequency, the power of laser beam and the orientation of the crystal lattice. The lower frequency or higher power leads to slower group velocity of light.

Slow and superluminal light propagation in temporal nonlocal response Kerr media has been investigated. The group velocity, as low as tens of few centimeters per second, can be easily obtained by tuning the wavelength of a continuous-wave (CW) laser in a typical Kerr material, such as in alexandrite.

The stability of three coupled Bose-Einstein condensate (BEC) solitons is investigated by the variational approach in two conventional time-independent trapping potentials. The effects of parameters of the potentials and the initial conditions of the BEC soliton system on the stationary state and self-trapping are discussed. It is found that the trapping potentials play an important role in the stability of the system and change the characteristics of the system, and there are different critical potential amplitude values corresponding to different trapping potentials and initial conditions of the BEC soliton system.