摘要
提出采用光子级别的弱本振光(LO)与弱回波信号进行相干混频。接收单元采用多像素光子计数器(MPPC),光子混频中心频率为1MHz,本振光与回波光子光程差分别为30、45、60m。实验分析表明,在距接收系统的任何位置,其数据的功率谱密度(PSD)中均含有大量噪声成分。为减弱噪声的影响,采用功率谱密度叠加方法从噪声中提取信号,并采用匹配滤波算法将信噪比进一步增强。对距接收系统45m和60m处的混频信号进行6次功率谱密度叠加后利用匹配滤波算法进行滤波,信噪比分别提升5.90倍和2.73倍,且初始信噪比越高,滤波后信噪比改善越明显。
A frequency mixing method with photon counting level weak local oscillator （LO） and echo signal is put forward to decrease the shot-noise from the strong LO. The receiver is multi-pixel photon counter（MPPC）, the central frequency of the mixing signal is 1 MHz, and the optical path differences are 30, 45, 60 m respectively. The experimental analysis shows that power spectral density （PSD） of every data segment has a great number of noise no matter what the distances is. Accordingly, the method of PSD averaging is used to extract the signal from the deep noise, then, matched filtering method is also introduced to enhance the signal-to-noise ratio （SNR）. The PSD averaging and matched filtering method are adopted for the frequency mixing signal at the distances of 45 m and 60 m from the signal receiving system, as a result the SNRs are improved by 5.90 and 2.73 times compared with the original PSD signal, and the higher the initial SNR is, the more prominent the improvement of SNR is.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2013年第6期270-277,共8页
Chinese Journal of Lasers
基金
国家自然科学基金(61205143)资助课题
关键词
探测器
全固态单频激光器
光子计数
相干探测
信噪比
detectors, all solid sate single frequency laser
photon counting
coherent detection
signal-to-noise ratio
