研究一种采用光折变多量子阱器件的无线光通信自差拍接收方案。与寻常相干接收方案相比,省去了中频跟踪电子系统;与量子阱器件零拍方案相比,采用中频窄带滤波器,提高了接收端机的输出信噪比。理论上研究了自差拍相干接收方案,从其物理机制出发,结合信噪比分析,探讨了影响相干接收方案的主要因素。建立了该方案的实验系统,并开展了有意义的实验研究。理论分析及实验结果表明,该方案对激光大气传输所引起的诸多不利影响皆有一定的抑制作用,因而有可能应用于卫星地面激光通信和地面无线光通信系统。

Atmospheric optical wireless channel is a time-varying optical channel because of the effect of scintillation, the paper introduces rate compatible punctured turbo code (RCPTC) scheme to provide unequal error protection (UEP) for optical wireless communication. In order to use RCPTC over optical wireless channel, the paper firstly proposed a turbo decoder with iterative optical channel estimation for optical wireless channel. Simulations show that the proposed turbo decoder significantly improves the performance of system. Based on the proposed turbo decoder, the paper compares several RCPTC schemes via simulations. In these RCPTC schemes, the non-uniformly punctured code schemes are compared with uniformly punctured code scheme. Moreover, the systematic puncturing scheme and non-systematic puncturing scheme are both discussed.

In this paper the existence of optimal frequency detuning in the pumping process of the excited state Faraday anomalous dispersion optical filter ESFADOF, also referred as active FADOF.is reported. We measured this detuning and its variation versus cell temperature. Moreover, the dependence of the ESFADOF transmission on the cell temperature and pumping power was also studied experimentally. On the basis of these results, the transmission of rubidium 775.9nm ESFADOF was raised by more than two orders of magnitude under optimized working conditions. q1998 Elsevier Science B.V. All rights reserved.

What is, to our knowledge, a new kind of laser tree space communication syslem is reported. In this system, a laser diode is locked and tracked at the transmission peak of a Faraday anamolous dispersion optical filter (FADOF) so as to obtain a stabilized lasing. A Zeeman ab-sorption Fadof (Fadof/Zeeman) was employed as a stabillzed re-ceiver. The bandwidth of the Fadof/Zeeman is about 1 GHz. which is three times less than that of the FADOF. The tuning capability is about 1 GHz/0.01T. We successfuily conducted the audio and vlsual tele-phone optical communication experiment by means of this system in a strong solar baclground and compared the systematic property of the FADOF/Zeeman receiver and the interference filler (IF) receiver. The results show that the sensibilty of the FADOF/Zeeman eceiver is about 25 times higher than that of the IF.

We report a digital speace iptical communication svstem with new features both in the transmitting and in the receiving ends. The diode iaser source is stabilized to within=100kHz by locking its frequency to the transmission peak of a Faraday anomalous dispersion iptical filter FADOF1, The optical filter in the receiver usestwo FADOF's that are linked to eliminate the muitipeak strueture and achieve a single-peak bandwidth of i GHz. The detection sensitivity of this system is 23 times higher than that of a system with a traditional interference rilter.