1.5μm外腔半导体激光源外差FSK相干光纤通信系统的研究  

1.5μm Experimental Heterodyne FSK Coherent Optical Fiber Communication Systems with External Cavity Semiconductor Lasers

作　　者：管克俭 郭建恩 叶培大 李玲 蒋佩璇 

机构地区：[1]北京邮电学院光通信教研室

出　　处：《通信学报》1992年第1期52-57,共6页Journal on Communications

摘　　要：本文报导采用国产器件建立的1.5μm波段外差FSK相干光纤通信实验系统。系统中发送光源和本振光源分别采用InGaAsP自聚焦棒(GRINROD)外腔和光栅外腔半导体激光器,笔者对大频偏、单滤波/包络检波系统和小额偏、单滤波/差分—延迟检波系统进行了研究。在这两个系统中,中频(IF)经AFC分别稳定在1.05 GHz4±1 MHz和810MHz±1MHz。140Mbit/s信号经6.4公里单模光纤(损耗约为0.62dB/km)传输后,经光电混频、预放、中放和中频滤波后进行包络检波或差分一延迟检波,检波后的信号经基带放大和基带滤波后进行取样、判决。经测量:系统的误码率BER≤10^(-8)(半小时观测时间),系统的接收灵敏度为-37.7dBm(BER≤10^(-9),系统的损耗余量为24.92dB。实验中,笔者对IF电路进行了优化设计,同时,利用中频谱对发送光源的调频特性进行了深入的研究。实验结果表明,只要选择合适的GRINROD外腔的尺寸,可以得到不同线宽的激光源,进而可以建立不同相干程度的相干光纤通信系统。In this paper, the 1.5 °m experimental heterodyne FSK coherent optical fiber communication systems in which all components are designed and fabricated domestically, are reported. In the experimental system, the InGaAsP GRINROD and grating external cavity semiconductor lasers are used as transmitter and local oscillator, respectively. The wide frequency deviation, single filter/envelope detection system and the narrow frequency deviation, single filter/differential detection system are studied. In these two systems, the intermediate frequency (IF) center frequencies are stabilized at 1.05 GHz±1 MHz and 810 MHz±1 MHz, respectively, by an AFC. After the 140Mbit/s, 24 bit NRZ programme pattern is transmitted through 6.4 kilometers single mode optical fiber (the loss is about 0.62dB/km), it was mixed, amplified, bandpass filtered (0.639-1.1 GHz) and demodulated by an envelope detector or a differential/delay-line demodulator. The demodulated baseband signal was amplified, post-detection filtered (0-98 MHz), sampled and then fed into decision circuit. The measured system performances are: the Bit Error Rate BER≤10-9 (observed within half an hour), the receiver sensitivity is-37.7dBm (BER≤10-9), the span loss margin is 24.92dB. In the experiments, the IF circuits are designed optimally, meanwhile, the frequency modulation characteristics of the transmitter is exhaustively studied by means of IF spectrum. The experimental results show that various kinds of coherent optical fiber communication systems can be set up, if the proper GRINROD external cavities are chosen.

关 键 词：光纤通信 半导体激光源 FSK 

分 类 号：TN929.1[电子电信—通信与信息系统]