Error rate analysis of few-mode fiber based free-space optical communication.

Few-mode fiber (FMF) based receiver emerges as a promising solution for free-space optical (FSO) communication due to its excellent performance in the presence of turbulence. We propose a theoretical model that uses the coupling efficiency of FMF to evaluate the performance of FMF-based FSO system in the presence of turbulence. The series solutions and asymptotic solutions to bit-error rate (BER) of such system are derived for maximal-ratio combining (MRC) scheme and equal gain combining (EGC) scheme over the Gamma-Gamma turbulence channels.

Unidimensional Two-Way Continuous-Variable Quantum Key Distribution Using Coherent States.

We propose a unidimensional two-way continuous-variable quantum key distribution protocol with coherent states, where the sender modulates a single quadrature of the coherent states rather than both quadratures to simplify the structure of a two-way system. Security analysis is performed with a general attack strategy, known as two-mode attack, which helps to reduce limitations in the analysis. The performance of the protocol under all accessible two-mode attacks at fixed distance is illustrated.

Performance enhancement of free-space optical communications under atmospheric turbulence using modes diversity coherent receipt.

This paper numerically and experimentally investigates the performance of free-space optical receiver using modes diversity coherent receipt under moderate-to-strong turbulence. By utilizing a three-mode photonic lantern with digital maximum ratio combining, a 40 Gbps QPSK optical signal is received. The turbulence strength is measured by the ratio of beam diameter to atmospheric coherence length, D/r0.

[The effect of different dispersive methods on flexural strength nano-ZrO(2) reinforced denture polymethyl methacrylate].

Purpose: To study the effect of different dispersive methods on flexural strength of nano-ZrO(2)/polymethl methacrylate(PMMA) composite samples.

Methods: The nanometer ZrO2 particles which were modified by coupling agent Z-6030 were mixed to PMMA as the filler materials (3%) by means of handle disperse, ball milling disperse and ultrasonic wet disperse, respectively. Pure PMMA was used as blank control .

[Influence of different amount of silane coupling agent on the flexural strength of PMMA/nanometer ZrO2 composites].

Purpose: To study the influence of different amount of silane coupling agent Z-6030 on the flexural strength of PMMA/nanometer ZrO(2) composites.

Methods: Nanometer ZrO(2) particles were modified by silane coupling agent Z-6030 with different percentages.In situ polymerization method was used to combine PMMA/ nanometer ZrO(2) composites of denture base plate.

[Clinical analysis of colour distribution in tetracycline teeth].

Purpose: To analyze the colour range and distribution of tetracycline teeth, and the difference from normal teeth.

Methods: 142 cases with 468 anterior tetracycline teeth and 100 cases with 200 normal anterior teeth were collected. The color was measured by a computer-aided Shade-Eye NCC colorimeter, and expressed in terms of 3 coordinate values (L,a,b) of the CIE-1976-Lab color system.