Sensitivity enhancement using coherent heterodyne detection
Sensitivity enhancement using coherent heterodyne detection
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DOI：
10.1109/50.296196
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发表时间：
1994-06
影响因子：
4.7
通讯作者：
G. Lachs;S. M. Zaidi;Ashutosh Kumar Singh
中科院分区：
文献类型：
--
作者：
G. Lachs;S. M. Zaidi;Ashutosh Kumar Singh
本文着重讨论了在光纤通信系统中相干检测(CD)相对于直接检测(DD)的一些迄今被忽视的优点。这些灵敏度提高的基础是相干光纤系统中的本地激光器将大量光子添加到净接收的光信号中。在这些条件下，玻尔对应原理使我们能够经典地处理光电二极管输出信号。具体地说，通常的CD环境产生的光电二极管输出可以被视为受高斯噪声干扰的经典信号(中心极限定理)。这一检测过程已经得到了广泛的研究，并且有许多强大的信号处理技术可以用来提高系统的灵敏度。具体地说，我们利用数字调制的子载波的和来对光载波进行频率调制，并借助于相干检测来获得由计算机模拟确定的11.1光子/b的灵敏度。>；
This paper focuses on some heretofore overlooked advantages of coherent detection (CD) over direct detection (DD) in optical fiber communication systems. The basis for these sensitivity improvements is the fact that the local laser in coherent fiber optic systems adds a large number of photons to the net received optical signal. Under these conditions, the Bohr correspondence principle enables us to treat the photodiode output signal classically. Specifically, the usual CD environment yields a photodiode output that can be regarded as a classical signal disturbed by Gaussian noise (central limit theorem). This detection process has been studied extensively, and there exist many powerful signal processing techniques that may be used to enhance system sensitivity. In particular, we utilize a sum of digitally modulated subcarriers to frequency modulate an optical carrier along with the aid of coherent detection to achieve 11.1 photons/b sensitivity as determined by computer simulation. >