高载噪比多载波光源的噪声抑制理论及实验研究  

Theoretical Analysis and Experimental Study of Noise Suppression for High-Carrier-Noise-Rate Multi-Carrier Light Source

作　　者：张霞[1,2] 白成林[1] 张晓光[2] 

机构地区：[1]聊城大学山东省光通信科学与技术省重点实验室,山东聊城252000 [2]北京邮电大学信息光子学与光通信国家重点实验室,北京100876

出　　处：《中国激光》2013年第11期170-174,共5页Chinese Journal of Lasers

基　　金：国家自然科学基金(61205065);高等学校博士学科点专项科研基金(20110005110014);深圳市科技研发资金基础研究计划(JC201105191003A);山东省自然科学基金项目(ZR2010FM043)

摘　　要：基于循环频移器(RFS)载波产生原理,创新性地提出了一种在循环频移环路中插入一个非对称马赫曾德尔干涉仪(AMZI),通过抑制噪声来提高信噪比的多载波产生改进方案。理论推导出光信号功率和放大自发辐射(ASE)噪声功率通过非对称马赫曾德尔干涉仪后的表达式。根据假设,在干涉仪两臂的光程差远远大于ASE噪声的相干长度,同时远远小于光信号相干长度的条件下,ASE噪声功率降低了3dB,而光信号功率没有改变。同时通过仿真和实验分别得到了50个子载波的输出。结果表明,基于该改进方案产生的多载波的载噪比可以达到37.5dB,比传统结构最多提高了17.5dB。According to the theory of multi-carrier generation based on recirculating frequency shifter （RFS）, a modified scheme for multi-carrier generation to improve signal to noise ratio （SNR） through noise suppression by inserting an asymmetric Mach-Zehnder interferometer （AMZI） in the RFS loop is proposed creatively. The formulas of optical signal power and amplified spontaneous emission （ASE） noise power after AMZI are deduced. According to the assumption that the AMZI arms optical path difference is much shorter than the coherence length of the laser and longer than the coherence length of the ASE noise, ASE noise is reduced by 3 dB without affecting the optical signals power simultaneously. 50 output subcarriers are generated with both simulation and experiment confirmations, respectively. The results show that carrier to noise ratio of the multi-carrier generated by the improved scheme can be as high as 37.5 dB and is up to 17.5 dB higher than the traditional structures.

关 键 词：光通信 多载波光源 噪声抑制 非对称马赫曾德尔干涉仪 

分 类 号：TN911.22[电子电信—通信与信息系统]