The TDFA (Thulium-Doped Fiber Amplifier) is a promising candidate for an amplifying device in S band. We established a bi-directionally pumped Thulium-Doped Silica Fiber Amplifier (TDSFA) with a single 1 064 nm pump wavelength in order to know the characteristics of the amplifier. The on-off gain was measured for simplicity. The gain varying with pump power and with signal wavelength was studied in detail. At the maximum launched pump power of 1 400 mW, the amplifier had a gain over a wide wavelength region of 1 485 to 1 517 nm, with a peak gain of 3.76 dB. Weak GSA (Ground-State Absorption) and strong ESA (Excited-State Absorption) limit the further increase of the gain. The results show that TDSFA is operable using such an upconversion pumping scheme.

An anisotropic piecewise gaussian filter (PGF) has been putted forward. In this method, not only the information of scale and orientation has been applied, but also piecewise method has been used to preserve edge. In this article, a statistic model of noise has been used to estimate the variance of noise and based on this the standard scale of image has been decided. Then the Hermite transform method has been used to determine orientation adaptively. By calculating the axial ratio and scale of gaussian model, the effective neighbor filter can be converted into piecewise gaussian filter. The experimental result shows that this new method has better capability than other often used method in suppressing noise and preserving edge.

The possibility of using a hollow-core Bragg fiber with cobweb- structured cladding to obtain low-loss transmission in wavelength range 0.65 μm～ 1.55 μm and 200 μm～ 500 μm is proposed and analyzed. The results show that the transmission losses of the hollow-core Bragg fibers with cobweb cladding are far less than the absorption losses of constituent plastics. Thus, using inexpensive plastics, it allows the fibers to meet the needs of transmission longer-distance and higher-bandwidth and to realize the wavelength division multiplexing(WDM).

Based on the analysis solution of a W-type double-cladding chiral optical fiber, the optical power characteristics of several lower-order guided modes have been investigated. The optical power in the core as a function of chirality parameters in the core, the inner and outer claddings is calculated for different inner cladding thickness. The effect of chirality parameters on the optical power in the core for guided modes with different index signs is discussed. Thicker inner cladding results in larger optical power in the core. With increasing the chirality parameter in the core, the optical power of HE-11 mode and HE-21 mode (HE01 mode) in the core increase slowly, but the power of HE11 mode and HE21 mode (HE02 mode) in the core decrease gradually. The effect of the chirality parameter in the cladding is reversed with that in the core.

Transmission Control Protocol (TCP) performance over optical burst switching (OBS) is experimentally investigated on OBS testbed. The effect of burst losses on TCP performance over the OBS testbed is studied. The result shows that burst losses will lead to a network wide drop in TCP throughput and higher burst loss probabilities will result in lower available TCP bandwidth. Then the effects of delay penalty and correlation benefit are investigated in detail. Taking into consideration these effects, experimental results show that there exists an optimal assembly period to maximize the TCP bandwidth, and the optimal value is about 250 μs in the testbed, which is independent of the burst loss probabilities. To make the OBS testbed work steadily and improve the performance of TCP over the testbed to the greatest extent, the chosen burst assembly period should be equal to or slightly greater than the optimal value.

The residual third-order dispersion of the optical phase conjugation process is detrimental to conjugated polarization solitons propagation in single-mode dispersion, resulting in more timing jitters. The dispersion-shifted fiber with positive TOD was proposed to use for compensating for the residual positive TOD at the fiber output. The numerical results prove it practicable and the physical mechanisms were also analyzed.

A scheme is proposed to teleportation of an unknown multi-atom entangled state, considering the entangled states of two or more particles play an important role in both demonstrating quantum nonlocality and quantum information processing. The scheme is based on the degenerate Raman interaction of a Λ-type three-level atom with a single-mode field. First let n atoms cross a coherent cavity field in succession to prepare a quantum channel. Then the sender lets the other n atoms which carry the unknown state cross the cavity in succession and makes a joint measurement by detecting the cavity field and the atoms separately. When |α|(＞＞)1, the cavity field can be detected with the measurement method of detecting orthogonal states. Finally the receiver reconstructs the initial state according to the outcome of the joint measurement transmitted through a classical channel. The advantage of the scheme is that it uses an entangled state of a coherent state with n atoms as a quantum channel, which makes the scheme simple and easy. The scheme is expected to be useful in demonstrating quantum nonlocality and information processing.