An analysis on the time-dependent formation of one-dimensional gray photovoltaic solitons under open-circuit conditions is presented.Quasi-steady state and steady state gray solitons are obtained from the time-dependent propagation equation.Results show that the solitons have intensity-independent widths in quasi-steady-state regime and their formation time is inversely proportional to the ratio of soliton peak intensity to dark irradiance.And,the study of propagation properties of open-circuit gray solitons indicates that they are relatively stable under perturbations at least less than 10%.

A chemically stable Er3+/Yb3+ codoped phosphate glass is prepared and used in fabrication of planar waveguides for optical amplifiers and lasers. The weight loss rate of this phophate glass is 4.7×10-5g·cm-2·hr-1, which is smaller than that of Kiger′s commercial phosphate glass QX/Er. Planar optical waveguides are formed by Ag+-Li+ ion exchange and the effective refractive indices are determined by m-lines at 632.8nm. Diffusion parameters such as ion exchange depth, surface refractive indices, variation of refractive index and diffusion coefficient are calculated based on refractive index profiles obtained by Inverse WKB method.

Based on the complexity of fabricating the taper fiber and the performance in transmission of the image bundles,through applying the technology of combining step motor and computer,controlling the usual optical fiber double crucibles drawbench out-nozzle diameter and tub wheel′s rotating speed at the same time,of a way fabricating the taper fiber with numerical control,whose length can reach to 1m,is realized.Two image taper fiber bundles with the different ratio of radius are made.Compared with the ususl way that enlarging the volume of the tub wheel,this technique is smaller in the volume,easier to manipulate,easier to control the ratio of radius,more endurable to strain.At last we analyses the mode wastage of the taper fiber.

By analyzing the action of a beam splitter on squeezed vacuum states (SVSs), it is found that, if the two input light beams of the beam splitter have the same squeezing amplitude and phase, the output state is a two-mode SVS. If the two input light beams of the beam splitter have the same squeezing amplitude but a phase difference of π, the output state is a direct product state of two single-mode SVSs. In the two-mode SVS, each mode has the same photon number with both even and odd photons, while the single-mode SVS which contains only even-number photon in the photon number-state representation. Based on these results, a scheme to divert the entanglement of entangled SVS from its initial locations to another location is suggested. In this scheme, the two SVSs are utilized as the quantum channel. The process of the entanglement diversion is achieved by using the 50/50 symmetric beam splitters and the photon detectors with the help of classical information.

Erbium-doped fiber amplifiers (EDFAs) with low-cost long-period fiber gratings (LPFGs) fabricated by high-frequency CO2 laser pulses are investigated theoretically and experimentally. Results shows that Performances of EDFAs for both single-wavelength and multi-wavelength applications can be improved via inserting a LPFG into the erbium-doped fiber (EDF) as an ASE noise filter or a gain equalizer. Optimization of an in-line EDFA with a LPFG is also provided. The NF of such an in-line EDFA is improved by ～0.5 dB and its small-signal gain is enhanced by 7 dB, compared with that without filtering. A multi-wavelength EDFA with a gain flatness of ～1.5 dB is simply achieved via inserting a LPFG into the middle of an EDF as a gain equalizer, accompanying with a gain improvement of ～1 dB and a NF reduction of ～0.1 dB compared with the EDFA having a LPFG located after the EDF.

The evaluations of aero-optic effects for subsonic airborne electro-optical (EO) system from shear-layer cavity flow are presented. Compressibility effects in the shear layer are measured by convective Mach number 0.8, the geometry of cavity is L/H=6.7 and the average cavity temperature is T=230 K. Numerical simulation of this unsteady two-dimensional flow using the commercially available software CFD code has also been carried out and it proves that Strehl ratio improves with wavelength increasing;however, the dispersion angle is complex. The wavelength effect on the system performance is also theoretically validated and then an optimum wavelength model λ*=2πσt is given.

For a small planar source, an accurate description of the far-field error in terms of the source error was presented based on a far-field asymptotic solution of the Helmholtz equation. The "critical point" of the far-field phase error was derived, analyzed and proposed to decide the off-center source error with the "relative error volume". Numerical results were also given to examine this method. It is shown that the off-center distance influences the far-field errors significantly, which can be used to describe the source error and analyze the far-field errors, and the source error for the inverse problem can be estimated by the "critical point".