In intersatellite communications, wave front aberration is main factor in affecting far-field behavior of signal beam. In this paper the influence of coma and spherical aberration on the far-field distribution and antenna receiving power is analyzed, in which aberration attenuation factor is introduced and the relation of it to root mean square (RMS) of wavefront aberration is given. The results show that the deeper coma and spherical aberration are, the heavier the influence on receiving power is. In the condition of the antennae being aligned correctly, receiving power becomes half of that for signal beam without aberration, when the values of root mean square for coma and spherical aberration are 0.120A and 0.135A, respectively. The influence of coma on receiving power is mainly caused by the moving of the intensity peak, and for spherical aberration it is the increasing of secondary intensity peak.

Yuqiang Yang;Liying Tan;晶 马;Qiqi Han;Jianfeng Liu;Jianjie Yu;Yang Yang;Lili Gong

Zhongguo Jiguang/Chinese Journal of Lasers

2008-3

In practice, due to the need of high data rate and long range, the coherent laser communication system with high responsivity has a potential advantage in satellite-to-ground links. The mixing efficiency at the receiver aperture is affected by atmospheric turbulence. In this paper, we try to derive exact expressions for the probability density function of the mixing efficiency in the presence of turbulence. The distribution of the mixing efficiency is given in different phase residual variance after using adaptive compensation techniques (ACT). The work in this paper is aimed to enhance coherent laser communicat ion quality of satellite-to-ground by analyzing the mixing efficiency with ACT.

Yu Siyuan;Bao Fangdi;Ma Zhongtian;晶 马;Tan Liying

2015

The coupled motion between the gimbals of the optical terminal and satellite platform is the key factor to influence the antenna pointing control process of the satellite optical communication (SOC) terminal. In this paper, based on the satellite attitude dynamics, we studied the antenna pointing error induced by the coupled motions under different parameters of the gimbals motion. The analysis results indicated the antenna pointing error change regularly with increase of the rotation angle of the gimbals, and reach the max value when the azimuth angle and elevation angle are (π, 0) and (-π, 0) separately. With increase of the rotation time, the pointing error increase slowly. The amplification of the pointing error is only 1% with the rotation time change from 10 s to 1000 s. The results of this paper are the basis of the antenna pointing error compensation research and will improve the stability of the SOC system applied on the satellite platform.

Jian Feng Liu;Qi Qi Han;Si Yuan Yu;晶 马;Li Ying Tan

Yuhang Xuebao/Journal of Astronautics

2007-7

We derive the bit error rate (BER) of inter-satellite laser communication (lasercom) links with on-off-keying systems in the presence of both wave-front aberrations and pointing error, but without considering the noise of the detector. Wave-front aberrations induced by receiver terminal have no influence on the BER, while wave-front aberrations induced by transmitter terminal will increase the BER. The BER depends on the area S which is truncated out by the threshold intensity of the detector (such as APD) on the intensity function in the receiver plane, and changes with root mean square (RMS) of wave-front aberrations. Numerical results show that the BER rises with the increasing of RMS value. The influences of Astigmatism, Coma, Curvature and Spherical aberration on the BER are compared. This work can benefit the design of lasercom system.

Yuqiang Yang;Qiqi Han;Liying Tan;晶 马;Siyuan Yu;Zhibin Yan;Jianjie Yu;Sheng Zhao

Optics Communications

2011-6-1

The erbium doped fiber, optical isolator and WDM coupler, which are three key optical components of commercial erbium-doped fiber amplifier (EDFA), are radiated to the radiation dose of 5krad by electron. The radiated erbium-doped fiber (EDF) make the output power of EDFA come down 0.5dB when the input power is between -12dBm and-5dBm. The NF climb up 1dB. However, the peak wavelength changes little. The radiation experiment results also show that the deterioration of the optical isolator and WDM coupler can be neglected at the dose of 5krad. In order to assure the accuracy of analysis, the recovery experiment has been done to correct the radiation effect on the EDFA. The results indicate that if optical communication systems have enough redundancy, the EDFA can be used on the low dose orbits without any radiation protection for inter-satellite optical communication.

Li Mi;晶 马;Tan Liying;Zhou Yanping;Yu Siyuan;Yu Jianjie;Che Chi;Lu Chunlian

Proceedings of SPIE - The International Society for Optical Engineering

2008

We have analyzed the displacement damage effects on quantum dot lasers theoretically and deduced the relation between the radiation-induced threshold current change and the neutron fluence. The neutron radiation experiment for quantum dot lasers are also carried out to examine the displacement damage coefficient of the non-radioactive recombination rate. The formula fits the experimental data very well, and can describe the trend of the laser performance under electron irradiation. It can also predict the behavior of quantum dot lasers under radiation environment and is valuable for practical application.

Chi Che;Qing Feng Liu;晶 马;Yan Ping Zhou

Wuli Xuebao/Acta Physica Sinica

2013-5-5

The InAs/GaAs quantum dot laser diodes and corresponding quantum dot samples are irradiated by 1 MeV electron. The laser performance and quantum dot photoluminescence intensity at room temperature are enhanced over a fluence range of 4 × 10 ¹³ cm ^-2. The radiation-induced defects increase the efficiency of carrier transfer to the quantum dots, which results in the improvement of photoluminescence performance under low level displacement damage. The contact resistant of quantum dot lasers decreases because the ohmic contact is also improved by electron irradiation.

Chi Che;Qiqi Han;晶 马;Yanping Zhou;Siyuan Yu;Liying Tan

Laser Physics

2012-8

Many small aperture satellite optical communication terminals utilize a periscope as the Coarse Pointing Appliance(CPA), however, the model of coarse tracking arithmetic becomes much complex since the optic structure of the periscope-type CPA varies with the angle of attitude in the CPA . To improve the tracking accuracy of the CPA, this paper researches coarse tracking arithmetic of periscope-type satellite optical communication terminals. Based on the optical matrix method, a matrix model with geometric optics for tracking in the periscope-type inter-satellite optical communication terminals was established. After obtaining the CCD-based angle measuring model, an automatic tracking model of the CPA was derived to implement the fast tracking for the target beams. A test was performed to testify the arithmetic. The test results prove that the tracking arithmetic can express the configuration of optical system exactly, and can process the information of locality from CCD accurately. The average tracking accuracy is less than 10 μrad. The test results also show that the tracking model can meet the requirements of the satellite optical communication. The method proposed in this paper would supply some helps for similar optical study.

Li Ying Tan;Shi Chen Wu;Qi Qi Han;晶 马

Guangxue Jingmi Gongcheng/Optics and Precision Engineering

2012-2

We analyze the performance of a satellite-to-ground downlink coherent lasercom system taking into account the combined effects of atmospheric wavefront aberration and tracking error of the receiver. We revise the wavefront phase variance in the case where the tracking error of the receiver terminal is present. We consider the example of the BPSK modulation scheme and show that the tracking error of the receiver terminal greatly increases the bit error probability of the coherent system. We show the optimum aperture diameter of the receiver. This study can benefit the satellite-to-ground downlink coherent lasercom system design.

Liying Tan;Qingbo Yang;晶 马;Siyuan Yu;Qiqi Han;Yijun Jiang

Journal of Russian Laser Research

2011-5

The coaxial two-mirror reflective telescope was usually used within a typical satellite laser communication terminal, which has the disadvantage of small field of view and low emission efficiency. In order to eliminate the inherent defects of the existing coaxial two-mirror reflective telescope, and improve the pointing and tracking efficiency of the satellite laser communication system, off-axis three-reflective optical telescope was designed for satellite laser communication terminal. The initial structure of the off-axis telescope was deduced according to the basic aberration theory, and the off-axis three-mirror reflective telescope with more lager field of view and higher efficiency was given. Simulation results of modulate transfer function, spot diagram, diffraction encircled energy and wavefront error all show that the off-axis three mirror reflective structure has the better performance compared with the coaxial two-mirror reflective structure, and meets the increasing design requirements of satellite laser communication system.

Jianjie Yu;Xuanjiao Li;Liying Tan;晶 马;Qiqi Han

Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering

2013-7